Military and Aerospace Case Studies - National...

Military and AerospaceCase Studies

Customer Case StudiesThis booklet contains a collection of customer case studies in the military and aerospace industry. Learn how engineers

and scientists are using National Instruments computer-based measurement and automation products in their test,

control and design applications. NI technologies increase productivity and lower cost through virtual/synthetic

instrumentation and graphical system design. This unique approach to embedded design, industrial control, and

test and measurement combines commercial, off-the-shelf (COTS) technologies with innovative software and hardware.

ni.com/ukni.com/irelandni.com/aerospace

Military and Aerospace Case Studies

NI has helped more than 25,000 companies around the world improve their automated test and measurement strategies.

NI customers save time and money using the latest technologies including multicore processors, programmable FPGAs and

rugged PXI test systems. Read some of their brief stories or visit ni.com/success to read full case studies from these

companies and more.co

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RF Data Transmitter/Receiver

Three-Phase Electrical Motor

F-35 Joint Strike Fighter

Automated TestLockheed Martin Simulation, Training & Support (LM STS) developed a standard test system for avionics suppliers to the joint strike fighter (JSF) program. The system uses NI TestStand, LabVIEW and LabWindows™/CVI software for core test management and ANSI C test development. LM STS estimates its standardisation approach to the F-35 JSFprogram has already saved the U.S. government millions of dollars and has the potential to save hundreds of millions more over the life of the program.

Read more about the Lockheed Martin case study on page 28.

Simulation and ControlBAE Systems Avionics (now Selex Sensors and Airborne Systems), designer and manufacturer of electronic warfare and surveillance systems, used the PXI platform with LabVIEW andreconfigurable I/O modules to implement a full digital motor controller on a Xilinx FPGA.Through rapid controller prototyping with the National Instruments LabVIEW FPGA Module,BAE was able to test and further develop their system on real hardware before starting theFPGA design. BAE was able to provide a system demonstration for their customer with minimaltime and equipment investment through COTS FPGA hardware without having to learn VHDL.

Read more about the BAE Systems Avionics case study on page 73.

ni.com/aerospace

High-Speed CommunicationsHarris, an international communications and information technology company, tests RF data transmitters and receivers. Using PXI instruments from National Instruments and anexternal wide area network transceiver integrated circuit on a custom-printed circuit board,Harris implemented a complete serial bit-error-rate test system that reduces cost per unitapproximately four times and offers customisation capability to communication interfaces that have added test requirements.

Read more about the Harris case study on page 52.

The world’s top 10 defence contractors rely on NI test systems.

ni.com/aerospace

Military/Aerospace Case Studies

Automated Test

Large Scale System Integration Utilising GOOP Programming Techniques and Automatic Eurofighter Front Fuse Testing

BAE Systems/TBG Solutions 5

Using LabVIEW and PXI to Develop a Performance Verificationand Fault-Detection System for U.S. Navy Submarines

BCO, Inc. 6

Developing a Test System for the Motorised Pumps and Reservoirs of the Airbus A380 EBHA

Bimal Automazioni 7

Performing Data Acquisition Based on LabVIEW Onboard a NASA AircraftCalifornia Institute of Technology/ Jet Propulsion Laboratory (JPL)

8

Wind Tunnel Data Acquisition and Control System Captronic Systems Pvt. Ltd 10

Portable Platform for Electrical Actuator Testing Conekt 12

Diagnostic Sonar Acquires and Processes Ultrasonic Phased ArrayImage Data with NI LabVIEW and PXI

Diagnostic Sonar Ltd. 14

Designing High-Speed Digital Tests for Military Defense Systems EDA Industries SRL 16

Building an Ultrasonic, Nondestructive Test System for the U.S. ArmyUsing NI Modular Instruments and LabVIEW

FBS, Inc. 18

In-Flight Stress Testing of Airplane Propellers Using LabVIEW Focus Software Inc. 20

LabVIEW and SCXI Provide a Configurable Measurement System for In-Flight Helicopters

G Systems 21

Lockheed Martin Reduces Costs and Time Testing F-35Joint Strike Fighter with LabVIEW Real-Time

G Systems 22

How to Build and Tune Multicore Enabled LabVIEW x86 Client DLLs Hitex UK Ltd. 24

New Innovation for Pressurised Cabin Functional Test on Aircraft Indonesian Aerospace 26

LM-STAR NI Software-Based Test System Saves Millions Lockheed Martin STS 28

“SCOUT” High-Performance Short-Wire Mass Interconnect for PXI MAC Panel Limited 29

U.S. Air Force Increases Mission-Capable Rates with PXI Mantech Test Systems 30

NASA uses NI LabVIEW to Save Time, Reduce Costs in Automated Testing of Microshutters

Mink Hollow Systems 31

Development of an In-Engine Turbine Traverse System Richmond Measurement Services 33

Viper Jet Engine Test Bed: Delivering Flexibility and Reliability through an Integrated Hardware and Software Data Gathering Platform

SCITEK Consultants Ltd 35

Implementing an NITestStand Process Model for Avionics Burn-In Testing Serco Test Systems 37

ni.com/aerospace

High-Speed Communications

Using National Instruments Software and Hardware to Develop an Automated Test System for Satellite Communication Equipment

Aegis Group 41

Developing Digital Test Equipment for Navy Aircraft Communications Using NI LabVIEW and PXI

ALE System Integration 42

PXI-Based RF Antenna Testing System B & B Technologies, an NTS Division 43

Wireless Data Collection System Across a Large Area B & B Technologies, an NTS Division 45

BAE Systems Uses PXI and NI LabVIEW to Develop an Efficient RF Cable Test Suite for the Eurofighter Aircraft

BAE Systems/TBG Solutions 47

Automatic Test Equipment for Radar Testing and Qualification Fiar S.p.A. 49

Using R Series Intelligent Data Acquisition for Bit-Error-Rate Test Harris RF Communications Division 52

Advanced Topologies for System-Level Testing and PCB Configuration JTAG Technologies 54

Northrop Grumman Uses NI LabVIEW and DIAdem for Rapid Telemetry Data Management

Northrop Grumman Space Technology 55

Designing an Automated RF Test System for Flexible Data Mining and Reporting with NI LabVIEW and DIAdem

Summitek Instruments 56

Spectrum Monitoring and Interference Analysis Using NI PXI Summitek Instruments 58

M&CVIEW: Satellite Ground Station Monitoring and Control System Based on LabVIEW

TELESPAZIO 59

The United States Army Uses LabVIEW to Develop Next-Generation Night Sky Spectrometer

United States Army RDECOM CERDEC 61

Using LabVIEW to Rewrite the Software of an Electronic Warfare Simulator United States Army 63

Radio Frequency Test Stands for Remote Controllers V I Engineering 64


ni.com/aerospace

Simulation and Control

Acquired Data Solutions Uses FlexMotion and LabVIEW to Build Unmanned Test Station for Aircraft Components Testing

Acquired Data Solutions 67

Digital Control of a Michelson Interferometer Testbed Demonstrator for a Satellite Telescope

Alcatel Alenia Space Italia 68

Hardware-in-the-Loop Made Easy by Using NI PXI and LabVIEW Real-Time Averna/Thales 71

BAE Systems Develops Field-Orientated Control of a Three-Phase Brushless Permanent Magnet Motor

BAE Systems Avionics 73

Data Acquisition and Control System for Testing Aerospace Fluidic Components Cal-Bay Systems, Inc. 75

Multi-Point Temperature Control System for Simulated Space Environment Cal-Bay Systems, Inc. 76

Aircraft Actuator Life Cycle Testing Cal-Bay Systems, Inc. 77

Using National Instruments PXI-CAN to Monitor Avionics Control Panels for the Boeing 787

Korry Electronics 78

Lockheed Martin Uses NI LabVIEW Simulation Interface Toolkit and PXI for Flight Simulation Model Development

Lockheed Martin Space Systems Company

79

Automated Control and Measurement of Chemical Agent Penetration Mink Hollow Systems 80

Development of a Dynamic Flight Simulator Politecnico di Torino 82

Simulating Aerodynamic Loading on an Aircraft Structure Using NI ProductsRichmond Measurement Services/NDT Services

84

Developing the Control Center for a New Green Rocket Propellant Test Bench at the German Aerospace Research Centre

S.E.A. Datentechnik GmbH 85

Developing a Monitoring and Control System for Structural Aircraft Tests Using LabVIEW and PXI

SITEM s.r.l. 87

Using CompactRIO to Develop a Rotocraft Unmanned Air VehicleUniversity of Bologna School of Engineering

89

Development of a Hardware-in-the-Loop (HIL) Simulator for a Rotary Wing UAVUniversity of Bologna II School of Engineering Forli

90


NotesMilitary/Aerospace Case Studies4

Automated Test

John Duncalf, Major Units Team Leader – BAE Systems (UK),

James Peter, Technical Director – TBG Solutions (UK)

THE CHALLENGEReplacing the existing test software by providing an effective softwarearchitecture to enable improved support and test reliability. Thisneeded to be done without stopping production for significant periods,and to ensure continued improvements can be easily incorporated.

THE SOLUTIONProviding a step change approach utilising a GOOP (graphical object-oriented programming) software architecture to provide bothmodular and extendable system components. This was achieved bydeconstructing the existing code into discreet modules and callingthem dynamically from a completely redesigned user interface (UI).

ni.com/aerospace 5BAE Systems/ TBG Solutions

Large Scale System Integration Utilising GOOP Programming Techniques and Automatic Eurofighter Front Fuse Testing

Hardware Hardware for the system consists of two test heads “bays” and aplant room. Each bay has around 1,400 input/output (I/O) channelsand the plant room has about 600 I/O channels. The I/O channelsare all connected via three independent RS485 networks of National Instruments FieldPoint modules and accessed via OPCservers, one for each RS485 network. In addition to the I/Ochannels, there are a variety of other instruments around the bays,mainly RS232 devices (DMMs and PALL contamination monitors)and two National Instruments PCI DAQ boards.

The original system software contained about 370 Mb of code,which represented around 35 years of development. The code in itsentirety was called from a single top level VI (virtual instrument) andcould take as long as five minutes to load into PC memory. Thismade the system very difficult to debug and almost unmaintainable.The most significant advance in stabilising the system was to breakthe code down into tests and tools modules.

Once the modules had been identified, they were retrofitted with some GOOP-class VIs that encapsulated the test data withinthemselves. Once this was achieved it allowed the modules to bedynamically loaded and unloaded from the system memory as theywere required. Thus the UI could be detached from the rest of thesystem code.

This reduced the memory footprint in the system dramatically, toaround 2 Mb for the UI plus 1 to 5 Mb, depending on which module is running at the time. Also, load times were reduced from minutes to seconds.

Other system improvements include distributing certain time-critical aspects of the system such as the E-stop handlingsubroutines to other parts of the network to bypass latency in the OPC servers. This was achieved using Compact FieldPointand LabVIEW Real-Time.

The Future In achieving the desired performance and flexibility, it has enabled us to plan for equipment obsolescence. Sections of the facility cannow be upgraded without affecting the rest. An example of this isthat the current RS232-driven DMMs will be replaced using NI PXI,controlled through LAN. This can be done, through the use of GOOP,in one test bay and without the need for major facility downtime.

Conclusion The understanding for the long-term development of this facilitywas laid down early. This made it easy to manage the developmentover the many months that followed.

The change to the GOOP-style programming has had a greaterthan expected return, in terms of flexibility, maintainability, codeperformance, rig reliability and cost savings.

The new architecture has enabled the system to be modifieddynamically to allow the support of developing products, in a flow-line production environment.

System architecture shows data encapsulation within the OOP classes.

Automated Test

Products:LabVIEW 7.1LabVIEW Datalogging and Supervisory Control ModuleLabVIEW Real-Time ModuleLabVIEW PID Toolkit

SQL ToolkitRS485FieldPoint Compact FieldPointNI Data Acquisition

Military/Aerospace Case Studies6 BCO, Inc.

Using LabVIEW and PXI to Develop aPerformance Verification and Fault-DetectionSystem for U.S. Navy SubmarinesBob Hartwell – BCO, Inc.

THE CHALLENGEDeveloping a small, rugged, and flexible performance verification andfault-detection system for U.S. Navy submarine combat systems.

THE SOLUTIONUsing NI LabVIEW and LabWindows™/CVI software and PXI hardwareto deliver a reliable, fully transportable transit-case configuration thatfits through a submarine hatch aperture and offers the flexibility foropen-ended product expansion.

Products:PXI/CompactPCI LabWindows/CVILabVIEW

Developing a Performance Monitoring andFault-Detection System for CommercialOff-The-Shelf TechnologyThere is a widespread and expanding use of commercial off-the-shelf (COTS) technology in combat systems to lower costs anddeliver superior performance. The U.S. Navy nonpropulsion electronicsystem for the Virginia class submarine makes widespread use of COTS technology to attain these benefits. However, the Navyanticipated a new class of logistical problems with this conceptbecause these combat systems needed to include fault detection and performance verification capabilities, not only when installedinitially but also when upgraded as a result of repair and replacement.Fault-detection systems typically include flexible technology, such as embedded software or hardware.

At BCO, we needed to determine if specific modules wouldperform as expected when operating in the intended nativestandard commercial industrial bus, the Versa Module Euro (VME)environment. This small business innovative research (SBIR) projectevaluated a hot-box test solution with the flexibility to support themajority of existing COTS software and hardware in the currentinventory with an initial target of six high-usage VME modules.

We developed a dual processing environment, with a nativeenvironment system (NES) and an independent stimulus andsupport (SMS) portion. The NES supports the VME devices in a self-contained “hot box,” containing target VME modules as eithersupport or units under test roles. The SMS contains a PXI/SCXIconfiguration that provides a user interface and test software run-time execution. The SMS controls and monitors the NES withserial communication, as well as multiplexed signal processingthrough the PXI/SCXI resources.

Rapid Development and Coordinationwith NI SoftwareUsing LabVIEW, we rapidly created and prototyped graphical userinterfaces and reviewed active prototypes with the U.S. Navy early in the development cycle. We also used LabVIEW to coordinatesoftware and firmware running on multiple processors on variedplatforms in real-time scenarios. We created a test executionengine using NI LabWindows/CVI software. With this test execution

engine, users can log on, select the test configuration, designatesoftware test modules to be run, observe the tests, and generatetest reports. This executive software also supports interprocesscommunications between our own test executive, our custom test modules, and vendor-supplied embedded self-test and interface utilities.

PXI Delivers a Small, Rugged, and Reliable Hardware SolutionWe delivered a configuration that met the system’s flexibilityrequirements using an NI PXI-based system. We selected PXIbecause of the product’s small, rugged architecture, and it offers a large number of modules to satisfy potential requirements in the future.

In addition, PXI delivered the proven reliability for the system to function for weeks or months while on a combat submarine.Finally, we needed a platform that would run our software basedon LabVIEW and LabWindows/CVI, so PXI was the perfect fit.

For more information, contact:Robert HartwellSystem EngineerBCO, Inc.799 Middlesex TurnpikeBillerica, MA 01821Tel: (978) 663-2525Fax: (978) 670-2939E-mail: [email protected]

The mark LabWindows is used under a license from Microsoft Corporation.Windows is a registered trademark of Microsoft Corporation in the United States and other countries.

System Block Diagram for the PXI and VME-Based Subsystems Onboardthe Submarine

Automated Test

ni.com/aerospace 7Bimal Automazioni

A. Damiani – Bimal Automazioni

THE CHALLENGEDeveloping a configurable, flexible, and reliable control and dataacquisition system to perform acceptance test procedures for themotorised pumps and reservoirs of the Airbus A380 Electrical BackupHydraulic Actuator (EHBA).

THE SOLUTIONUsing NI LabVIEW software and the PXI hardware platform to build afully configurable and powerful test sequencer for data acquisition tomeet the test requirements of our customer.

Our customer supplies aircraft air management: flight control,actuation, hydraulic systems, and landing gear, to the aviationindustry. They asked us to develop a test stand to perform theacceptance test procedures for the motorised pumps and reservoirsof the Airbus A380 EHBA.

We developed a test stand composed of two independentstations equipped with a separate set of mechanical and hydraulicinterfaces for both the motorpumps and reservoirs. The testsequences are composed of a running-in period and functional testsas proof of pressure, leakage, and performance test.

System Design We used NI PXI hardware and the LabVIEW graphical programmingenvironment to develop a real-time data acquisition and controlsystem for the test bench and a PC-based graphical user interface.We connected the two units with an Ethernet cable, and to facilitatedata communication, we took advantage of the built-in networkingfeatures in LabVIEW, including network published shared variables.

Software Features The host application runs on an industrial PC with a user interfacethat configures the system; performs tests, maintenance, andtroubleshooting; stores settings and results in a relational database;and manages alarms and warnings. The application consists of anautomatic test sequencer, and it can operate in four different modes: n Automatic mode keeps the testing time and necessary operator

actions to a minimum n Manual mode for failure investigations requires a step by step

input from the operator during all testsn Calibration and maintenance mode calibrates the measuring chain

of each channel and troubleshoots actions, so the user can set andadjust the hydraulic valves and electrical components

n Software editing mode gives the user the opportunity to makechanges to the test sequences

An automatic self-test feature is also provided to check valvesand transducers before normal operations start. Supervisors of thetest bench can evaluate test results with graphs, data, and reportsthat are saved at the end of each test sequence on a remote serveror locally in PDF and spreadsheet file format. To help the user duringmanual control maintenance operations, the interface displays aninteractive page showing the hydraulic diagram of the bench.

The real-time application running on the PXI controller realiseshigh-speed data acquisition and PID closed-loop control of theoutputs (setpoints of proportional valves), therefore satisfying theperformance requirements. Moreover, we can easily implementcommunication via CAN bus with the motor controller for the A380motorised pump using CAN hardware and NI-CAN software libraries.

The choice of an NI PXI real-time system instead of an industrialPLC system meant we could achieve real-time processing andadvanced analysis of acquired data that otherwise would have beentime consuming and difficult. Storing large amounts of data isessential to those tests where postprocessing is necessary.

The complete testing system was designed to be easilyupgraded to test new devices with similar design andfunctionality. Test sequences, parameters, and report templatescan be customised to create test procedures for new products.

Conclusion Using National Instruments software and hardware, we designedand developed a flexible and reliable testing system that resulted inimproved test accuracy and time savings for our customer. Wedeveloped the entire project using LabVIEW graphical systemdesign software and reduced costs, making maintenance of thesoftware easier. We are planning to use the same architecture onupcoming application projects.

For more information, contact:A. DamianiBimal AutomazioniE-mail: [email protected]

Developing a Test System for the MotorisedPumps and Reservoirs of the Airbus A380 EBHA

Test Stand, PC Cabinet, Remote Console, and Details of the Devices Under Test

Products:LabVIEWLabVIEW Real-Time Module

PXI/CompactPCINI-CAN

Automated Test

Product:LabVIEW

A test system based on LabVIEW was recently carried aloft in aNASA DC-9 “Vomit Comet”, that flew parabolic trajectories toacquire time-tagged data and video on how super-fluid liquid heliumbehaves in zero gravity. The purpose of this experiment was togather empirical data needed to validate and refine computermodels of how the helium responds to small perturbations whenweightless. The most direct applications of these models involvespacecraft design. Some spacecraft need to keep heat-sensitiveparts extremely cold – superfluid helium offers unique propertiesthat make it ideal for this purpose. A good example of such use ismaintaining uniform, cold mirror temperatures in space-basedinfrared telescopes.

The problem is that even at absolute zero, superfluid helium isstill a fluid, and fluids slosh around when disturbed. Superfluidhelium is one of the worst offenders because it has very littleviscosity or surface tension. As a result, a significant risk of causinginstability exists when maneuvering such a spacecraft, especially asmall one, unless this sloshing can be accounted for in the attitudecontrol system. Simply generating a computer model of the physicsof sloshing is not sufficient; an experiment was required to verifythe correctness of the model and make refinements. This involvedacquiring acceleration data and videotaping a flask of superfluidliquid helium while suspended in zero gravity – certainly not an easy task!

The Cryogenic Float PackageI was approached by the Low-Temperature Physics group at JPL tobuild the data acquisition (DAQ) system for this experiment. Theequipment consisted of two units, a tubular steel float package anda DAQ rack. The focus of the float package was a small, cylindricaldewar of liquid helium with a window on one end and a translucentgrid on the other. This flask was submerged in a larger steel dewarof liquid nitrogen to minimise heat transfer to the helium, ensuringsufficient time to perform the experiment before the heliumcompletely evaporated.

The outer dewar was fitted with a corresponding pair of windows,with a lamp mounted on one side and a video camera on the other.

The camera recorded the image of the helium bubble as it driftedagainst the background grid. A three-axis accelerometer mounted on the outer dewar measured the small g-forces acting on the heliumas it sloshed. A vacuum pump and a pair of Lake Shore cryogenictemperature probes monitored the transition to superfluidity as the helium was evaporatively cooled from 4.2 kelvins down to 1.4 kelvins during the experiment.

The second unit, the DAQ rack, was a half-height 19 in.instrument rack bolted securely to the deck of the aircraft, amodified DC-9 cargo jet. The rack contained a Hewlett-Packard dual DC power supply for the accelerometers, a Sony professionalVHS video tape recorder, a Horita time code generator module, avideo monitor, and the control computer, which was mounted onthe top of the rack. The control computer was a 100 MHz Pentium-based ruggedised “lunch box” portable computer made by Dolch,

running LabVIEW 3.1.1 under Windows 3.1. A National Instruments AT-MIO-16F-5 multifunctionDAQ board occupied one of the six full-sizeEISA/PCI slots in the computer. A Cirque touchpadtook the place of a mouse or trackball, neither ofwhich could be used in zero gravity.

The two units were connected by a bundled set of cables providing power to the float package and returningdata and video signals to the DAQ rack. Power for the entire system was provided to the rack from the aircraft power supply on two 15 A 120 VAC lines.

DAQ Software DesignThe major design issue for this project involved the synchronisationbetween the video frames recorded by the VCR and the data acquiredby the control computer. This was required so that investigators couldlater associate the g-forces on the helium bubble with its visualbehavior. Because the video was recording 30 images per second, the DAQ system needed to cycle at the same rate.

Timing for the main loop was provided by the Horita time code generator. Every 33 ms, the device transmitted a stream of 10 bytes, encoding the time and frame number to the PC serial port. This data was read with Serial Read VI but not decoded.

Immediately afterwards, the software read an array of seven analogvoltages from the MIO card. All data were stored in RAM in buffers to minimise overhead. Typical acquisition time for each parabola was40 seconds (1,200 samples), bracketing a 20-second period ofweightlessness. The operator was responsible for starting andstopping data acquisition by pressing the Enter key on the keyboard.

The operator interface was kept as simple as possible, both tominimise processing overhead and to relieve the operator of anyadditional stress of operating the system. After acquisition stopped,

Military/Aerospace Case Studies8 California Institute of Technology / Jet Propulsion Laboratory (JPL)

Performing Data Acquisition Based on LabVIEWOnboard a NASA AircraftF. Ted Brunzie – California Institute of Technology /

Jet Propulsion Laboratory (JPL)

THE CHALLENGEAcquiring video-synchronised acceleration and temperature datain zero gravity aboard a NASA research aircraft.

THE SOLUTIONUsing LabVIEW and a DAQ card in a ruggedised, portable PC to read time codes and acquire analog voltages.

“The LabVIEW software and data acquisition productsoperated with the rugged PC without a single problem;the system was regarded by the science team as the best part of the project.”

Automated Test

ni.com/aerospace 9California Institute of Technology / Jet Propulsion Laboratory (JPL)

the software translated the time codes from packed BCD format to time strings, translated the data acquired using the array tospreadsheet string VI, and wrote the resulting ASCII data to disk file.

Each parabola resulted in a separate data file being written todisk to maximise data security, another important design issue. To reduce chances of mistakes, an automatic file and directorygenerator was developed to maintain date and time-tagged files.Each flight resulted in 45 files being written to that day’s directory.We backed up data to floppy disk during the flight back to theairport each day. Between flights, we read the data into aspreadsheet program for further manipulation and critiquing of the experiment.

Experiment ResultsThe four days of flights were very successful, producing four videotapes and 180 files of time-tagged acceleration and temperaturedata. We developed the entire DAQ system within two months, justmeeting its very tight schedule and budget. The LabVIEW softwareand data acquisition products operated with the rugged PC withouta single problem; the DAQ system was regarded by the scienceteam as the best part of the project. Preliminary analysis of thevideo and recorded data indicates that several useful sequenceswere captured and will be incorporated in the physics models under development.

Ted Brunzie produces turnkey data acquisition, analysis, andcontrol systems at Caltech’s Jet Propulsion Laboratory, providingsupport for various NASA and industry research projects. Hiscurrent position as part of the JPL Measurement Technology Center follows an nine-year career in the Deep Space Networkdeveloping automated signal processing equipment.

The research described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under acontract with the National Aeronautics and Space Administration.

For more information, contact:Ted BrunzieTel: (818) 354-2542E-mail: [email protected]

Automated Test

Captronic Systems Pvt. Ltd

A wind tunnel is an aerodynamic test facility used to study flowpatterns around bodies and measure aerodynamic forces on them.A typical wind tunnel consists of a test section in which the aircraftmodel is kept, a contraction section and settling section before thetest section, and a diffuser after the test section. A fan after thediffuser creates the wind. This setup exactly simulates relativemotion between aircraft and wind.

Measurement systems for wind tunnel testing typically consistof static and dynamic force measurement, pressure profilemeasurement, and position measurement for orienting the modelwith respect to the wind direction.

System Configuration The data acquisition system is a PXI-based system containing NI SCXI-1125 modules for pressure measurement from thepressure scanners. Pressure ports in scanners are switched usingthe NI PXI-6527, which is also used for switching and monitoringthe status of isolation and butterfly and globe valves in the system.

The SCXI-1125 is used for acquiring pressure sensor outputs for calculating Mach number. The system uses six channels of an NI SCXI-1520 for acquiring force values from six component straingages. An NI PXI-7344 motion controller card controls theorientation of the model and incremental encoder, which isinterfaced with motion control card, and then sends the orientationinformation back to the system. A PXI-4472 is also used forvibration and sound pressure measurement.

System Implementation The software of the system is basically divided into two modules –calibration and acquisition modules.

Calibration Module – Software utilises five-point calibration forcalibrating pressure sensor, ESP (Electronic Pressure Scanner) andstrain gage balances. End-to-end calibration of force balance is donethrough the software for creating the calibration matrix. NI LabVIEW

is utilised for performing the calibration easily and provides veryaccurate results. The system also can validate the calibration.

The GUI Screen used when creating new calibration and pressurecheck for validating the calibration is shown in Figures 1 and 2.

Acquisition Module – There are two basic measurements involved in the above mentioned studies – pressure measurement, and forcemeasurement. Both measurements are carried in two phases: one foracquiring offset values from the pressure and strain gage balances,and the other for actual measurement. Offset value will be subtractedfrom the second phase of measurement then mapped to theengineering value.

Wind Tunnel Data Acquisition and Control SystemVijay. J, Application Engineer; Mondeep Duarah, Senior Manager –

Captronic Systems Pvt. Ltd, Bangalore, India

THE CHALLENGEDeveloping a full-featured, flexible and reliable test system for staticand dynamic force measurements of aircraft configuration andcomponents, air intake test for power plant – intake compatibilitystudies, small oscillation test for evaluating stability derivatives, largeoscillation and rotary derivative studies for modeling departure andspin of aircraft.

THE SOLUTIONDeveloping a reliable and highly accurate data acquisition and control system using the National instruments PXI and SCXI platform with LabVIEW Real-Time software.

Military/Aerospace Case Studies10

Figure 1. ESP Calibration Screen

Figure 2. Validation of Calibrated Pressures

Products: LabVIEWLabVIEW Real-TimePXI-1010 Combo ChassisPXI-8176 Real-Time Controller PXI-6052E DAQ ModulePXI-4472 Dynamic Signal Acquisition Module

PXI-7344 Motion Control Module

PXI-6527 Isolated DIO SCXI-1520 ModuleSCXI-1125 Isolated Analog

Input Module SCXI-1314SCXI-1313 Terminal Blocks

Automated Test

Captronic Systems Pvt. Ltd

Pressure Measurement The velocity profile over the aircraft model is acquired frompressure measurement from the fixed points over the model. This is achieved through electronic pressure scanners whose ports are connected to some fixed points in the model.

Before the actual acquisition, software controls the sequencerequired to maintain the flow velocity and to introduce the modelinto the flow stream. The user just has to enter the mach numberand the software controls the entire wind tunnel. During thepressure measurement, a motion control card is used to orientmodel to predefined positions.

National instruments LabVIEW software helped us to achieveswitching speed of ESP port to 2 kHz and saves money for thecustomer by reducing the entire operation period of the tunnel. We were able to achieve an accuracy of 0.01percent FS in pressuremeasurement. Figure 3 shows the pressure measurement window.

Force Measurement There are two types of force measurement involved in a wind tunnel – static and dynamic. Static force measurement involveskeeping the model in predefined position, and dynamicmeasurement involves moving model in predefined trajectory and acquiring the force values.

Force measurement involves first acquiring offset values fromthe model, keeping the model‘s predefined position or moving themodel in predefined trajectory and acquiring data. Then the actualsequence starts with opening isolation, globe, butterfly andpressure regulatory valve in sequence, and monitors its statusthrough NI DIO modules. Then the software checks the set mach number.

Once the set mach number is established, software moves the model into the stream of air flow. In case of staticmeasurements, the model is moved to a particular position and force data is acquired, then moved to another position and again force values are acquired, and so on. For dynamic force measurement, first acquisition is started, after that the model is introduced into theflow stream.

The model is then rotated to the same trajectory as that of wind off and the values are subtracted.

The challenge is controlling the model position and acquiring the force and position data simultaneously. Without the NationalInstruments motion control card and PXI, this would have beenimpossible with a single processor. The DSP processor in themotion controller helped us to do this job without muchcomplication and made these two operations independent and synchronised.

Vibration and Sound Pressure Measurement The accelerometers were connected to the PXI-4472 and wereused to measure vibrations of the model for the particular machnumber. Microphones were also connected to acquire the soundpressure level over the aircraft model for oscillation studies.

Conclusion The system developed is highly flexible and reliable for the above-mentioned aerodynamic studies. We were able to integratethe tunnel control, model pitching control and data acquisition toone system eliminating the need for three systems andcumbersome synchronisation.

Figure 3. Data Acquisition – Pressure Measurement

ni.com/aerospace 11

Automated Test

Conekt, UK

Products:LabVIEW 8.5M Series multifunction DAQ – USB-6216, USB-9211A

As a UKAS-accredited body specialising in aerospace validationtesting, Conekt was asked to support a test program for a series ofelectrical actuators. As part of this support, we supplied a set of testrigs capable of exercising and monitoring the electrical actuators atdifferent stages of the design process, from engineering developmentthrough validation testing and customer acceptance. To meet thechallenging functional requirements and delivery schedule, Conektdesigned a solution based on National Instruments technology.

The aerospace customer needed a fully portable final systemcapable of operating from both UK and U.S. mains voltages andsufficiently strong enough to withstand the inevitable knocks andscrapes likely to occur in transit.

The Rig DesignAlong with all the standard challenges implicit in providing a rig with anintuitive user interface and efficient unit control and monitoring, this rigalso had to be compatible with a wide variety of rotary and linear unittypes, each with varying degrees of complexity. Some actuatorsrequired the direct control of motor windings, whilst others wereoperated at a higher level simply by issuing commands to open andclose. With this rig, the user can specify various types of actuationoperation and measure a range of performance parameters, includingposition, current, and velocity. It handles all the required variants of theactuators in an efficient and user-friendly manner, monitoring anddisplaying the appropriate signals for each unit type with the option oflogging the data to file for later offline analysis. The system also buildsin the provision for the user to select a variety of external temperatures and voltages for display and logging, enabling a detailed record of thetesting environment to be maintained in the logfile. Each parametermeasured can also be assigned a user-defined failure limit to offerquick unit performance evaluation.

The Hardware Setup Given the wide variety of signals that the system had to measure and generate, National Instruments products, with their combinationof accuracy and flexibility, were the clear choice. We chose the NI USB-6216 device to handle the bulk of the signal interfacing. Withits combination of analogue and digital inputs and outputs, as well astwo counter/timers, it offered the perfect foundation for the system.

As an M Series device, the USB-6216 provides more than sufficientaccuracy, and the USB form factor, complete with integrated terminalblocks, ensured that the device footprint was minimal. The built-inisolation also guaranteed that the system was protected in the case ofunexpected transients or incorrect voltages being applied to theproduct connector.

We monitored external thermocouple inputs using an NI USB-9211A. Again, this M Series device offered the same balanceof function over form, providing the measurement of four temperatures with the minimum of space required, all controlled from a USB port.As with all National Instruments hardware, the integration with NIsoftware development environments ensured that the focus remainedon meeting the customer’s requirements, not on managing theinterface between different system elements.

In addition to the above hardware, we required anothercommercially available interface module, in the form of a PCI card, tomonitor the actuator under test. The availability of LabVIEW drivers,supplied with the card, ensured that we could easily integrate the PCIcard into the system.

Given this requirement for a PCI card, we had to source anappropriate PC. Keeping in mind the original requirement for a portablesystem, we selected a rugged fan-less industrial PC taking up lessthan 25 percent of the space of a standard desktop PC. As well asfulfilling the need for a compact test system, it offered a robustplatform on which to use the LabVIEW development environment.

To make the system self-contained, the enclosure also included apower supply to energise the unit under test, some custom circuitryfor unit control and monitoring, and a system cooling fan.

Alan Barlow, Senior Software and Instrumentation Engineer –- Conekt, UK

THE CHALLENGEDeveloping a fully portable aerospace electrical actuator testingsystem that is easily transportable between sites and supports a wide range of actuator variants with differing control strategies. Our aerospace customer needed to use the system at theirengineering development department, their customer site in the United States, and Conekt’s UKAS-accredited test laboratory.

THE SOLUTIONDesigning and building a compact, rugged test rig combining commercial off-the-shelf hardware and special-purpose circuitry, all controlled from a custom-designed software package writtenusing NI LabVIEW software. The rig is able to handle all the current variants of the actuators required as well as offer thepotential for supporting additional variants. Like all Conekt solutions, the test rig features an easy-to-use and intuitive userinterface and was fully tested using a formal validation process to ensure satisfactory operation.

Portable Platform for Electrical Actuator Testing


Automated Test

Figure 1. The Actuator Test Rig System Layout

Conekt, UK

The final solution is shown in Figure 1. The external temperatureinputs are provided on the front panel, with the industrial PC statuslights and USB connections easily accessible (see Figure 2).

The Software SetupWe achieved a substantial portion of the system functionality insoftware. LabVIEW was a natural choice for this kind of rig, given thenature of the mixed signals and the availability of the easy-to-usedrivers for all the interface hardware.

We designed the software using a structured approach by NationalInstruments certified developers within Conekt, ensuring that the endresult was robust and reliable and was delivered efficiently.

We were able to use our test equipment design experience, alongwith the flexibility and ease of use of the LabVIEW environment, toproduce a user interface that was both easy to use and highlyfunctional. Behind the user interface, we implemented a producer/consumer paradigm to ensure that the responsive nature of theinterface was not affected by any periods of rapid data collection andlogging.

We designed the flexible nature of the system configuration usingan ini file system, ensuring that the customer was able to add or editactuator configurations at a later date as appropriate using the intuitivetext-based layout of the ini files. To maximise the benefit of thesystem’s performance, we implemented two different data-loggingapproaches, both of which can be used simultaneously. One logfileformat recorded the summary test data, providing an overview of theunit performance over the full test running period (which could bemany days), whilst the other format recorded complete motionprofiles, containing position, voltage, current, and external input datalogged at 200 Hz.

System DeliveryThe system was delivered to our rigorous quality standards as well asthe customer-specified quality procedure. A comprehensive set ofacceptance tests were defined and carried out, giving the customerconfidence that each of the rigs delivered met the specifiedrequirements and was fit for the purpose.

For more information, contact: Alan BarlowConektTel: 01216 273505E-mail: [email protected]

Figure 1. The Actuator Test Rig Front Panel

ni.com/aerospace 13

Automated Test

Diagnostic Sonar Ltd.

Background Ultrasonic phased arrays have been used for many years for medicalimaging, but until recently they have enjoyed limited success innon¬destructive evaluation (NDE) due to cost and complexity.Diagnostic Sonar Ltd. has been using arrays for real-time imaging inaerospace NDE for three decades. This background has allowed us topioneer a major new capability – termed full raw data (FRD) collectionand processing – that offers significant benefits to the customer, butimposes new challenges for data acquisition hardware and software.

Conventional pulse-echo ultrasound array imaging involvesphased excitation of a group of elements from the ultrasonic array,with the differential delays between elements matching the differingpropagation paths to generate a beam with specific focus anddirection. The analogous reception process involves ecombining the signals from a similar group of elements after appropriatedifferential delays have been inserted. These delays can be varied with time so that the receive focus tracks the transmit pulse, aprocess termed dynamic focusing. The image is composed of asequence of beams scanned through the area of interest. The userperceives the performance to be real-time if frame rates exceed 15 Hz. However, area coverage requires significantly greater datarates, with 100 Hz rates routinely achieved.

In contrast, the FRD approach collects pulse-echo data from all transmit and receive element combinations and generates theresulting image by post-processing, permitting dynamic focus on transmit as well as receive for optimum resolution. This newtechnique also offers several unique processing possibilities, such as non-linear beam-forming and backscatter analysis.

Previous System Limitations Our previous imaging system, “FlawInspecta,” is PCI-based and usesNI image acquisition cards with LabVIEW to acquire the non-standardvideo format of the ultrasound image data. We chose LabVIEWbecause it fulfilled our primary requirements – rapid development ofsimple but powerful user-interfaces, easy control of both off-the-shelfand custom hardware, and real-time image acquisition and processingoffered by the NI Vision Development Module. This hardware andsoftware combination was well-suited to the “conventional” real-timepulse-echo imaging application. However, the imaging card’s single

channel limits the FRD area coverage rate. The only solution wasparallel acquisition, but multiple imaging cards for parallel acquisitionwas cost-prohibitive.

Diagnostic Sonar designed a phased array data acquisition systemfor real-time ultrasonic imaging using NI LabVIEW software and PXI hardware.

The NI System Solution The solution was to migrate to the new NI PXI-5105 multichanneldigitiser/PC-based oscilloscope, which is flexible enough to handle theimage format we need and offer a simple software upgrade path.

Each NI PXI-5105 acquires eight channels, allowing a single moduleto replace eight individual image acquisition cards and offering a majorcost and size reduction. We can implement a 32-channel acquisitionsystem with just four modules. The PXI-5105 also offers a performanceincrease, with 12-bit resolution at 60 MS/s compared to our previoussystem’s 10-bit resolution at 40 MS/s.

It is essential that all the acquisition cards are tightly synchronised,so we use a National Instruments PXI-7830R in the star trigger slot forthe critical timing and control functions previously implemented incustomised FPGAs.

With eight channels per module, high-resolution sampling (inamplitude and time), multi-record format, and a standardised driverinterface for LabVIEW, the flexibility and modularity of the PXI-5105provide a rugged system with virtually unlimited channel capability

Phased-Array Ultrasonic NDT with NI PXI-5105

David Lines – Diagnostic Sonar Ltd.

THE CHALLENGECreating a scalable, low-cost system for rapid acquisition of ultrasonic phased array echo signals for advanced non-destructive evaluation.

THE SOLUTIONUsing National Instruments PXI controllers and chassis, multichannelhigh-speed digitisers, and reconfigurable I/O FPGA real-time controllers with National Instruments LabVIEW software todesign a scalable acquisition system with tight timing and synchronisation to perform phased array data acquisition for real-time ultrasonic imaging.

Diagnostic Sonar Acquires and ProcessesUltrasonic Phased Array Image Data withNI LabVIEW and PXI


Products:LabVIEWLabVIEW FPGAOscilloscopes/Digitisers

PXI/CompactPCINI Vision Development Module

Automated Test

Diagnostic Sonar Ltd. ni.com/aerospace 15

so that we can easily configure systems to match customers’performance requirements and budgets.

Challenges The FRD approach introduces two major challenges. The first is theorder of magnitude increase in data, which could overwhelm the bustransfer capability. The onboard memory of the PXI-5105 provides abuffer so that the transfer constraint is limited by the average raterather than peak rate. In the event that we exceed this rate whenperforming very rapid acquisition over a small area, the onboardmemory is sufficient to hold all the data for transfer once theacquisition is over. The second challenge is the need to reconstructthe data into an image during acquisition. We found the speed of theNI Vision Development Module sufficient to perform this basicimaging on the fly.

Summary NI hardware and NI LabVIEW software had already proved their worthin the current range of Diagnostic Sonar “FlawInspecta” ultrasoundphased array imagers for non-destructive evaluation. Our new FRDacquisition approach offers many benefits to the customer, but theexisting single-channel configuration would result in a significant dropin area coverage rate. We needed multiple acquisition channels, butthe additional cost and size of multiple single-channel cards was notfeasible. The PXI-5105 offered a solution that is scalable to customerrequirements and has a multirecord capability that provides a simplesoftware migration path.

For more information, contact:David LinesBaird Road, Kirkton Campus,Livingston, West Lothian EH54 7BX, UK Tel: +44 (0)1506 411877 Fax: +44 (0)1506 412410 www.diagnosticsonar.com

“The PXI-5105 offered a solution that is scalable to customerrequirements and has a multirecord capability that providesa simple software migration path.”

Automated Test

EDA Industries SRL

F. Arcangeli, Rabah Derradji, L. Magni, and F. Magnino –

EDA Industries SRL

THE CHALLENGEDeveloping a high-channel-count digital test system with an openarchitecture that can leverage existing digital test patterns created for traditional digital instruments.

THE SOLUTIONCreating a flexible, digital test system with LASAR import capabilitiesusing National Instruments PXI hardware, high-speed digital I/O hardware, and LabVIEW software.

Designing High-Speed Digital Tests forMilitary Defense Systems

Products: High-Speed Digital I/OLabVIEWPXI/CompactPCI

Militaries have a growing need for maintainable test systems withguaranteed support and reliable operation. Budget reductions,increasing distances between a system’s manufacturer and the user,and the long life expectancies of these systems are all factors drivingthe need for improvements. Manufacturers recognise these challengesand provide specially designed systems capable of debugging andrepairing systems in the field. These repairing machines have become a critical component of many defense systems.

SELEX Sistemi Integrati, formerly known as Alenia Marconi Systems (AMS), asked EDA Industries to create a low-cost digital test system toassist in the repair and debugging of existing radar systems in the field.Our system was designed to meet the needs of the user (in this case,radar operators) as well as the manufacturer (SELEX Sistemi Integrati).

The radar operators required repair autonomy; an open,commercial off-the-shelf hardware platform; a reduction in repaircosts; and less reliance on third parties. The manufacturerrequested that our systems have low maintenance costs and theability to use existing test patterns, such as LASAR tap files, fromdigital simulator tools.

NI LabVIEW and PXI Hardware We selected the PXI platform from National Instruments as thefoundation for our digital test solution and created customapplication software using NI LabVIEW to meet all of SELEXSistemi Integrati’s requirements. With the virtual instrumentationcapabilities of LabVIEW, we were able to use low-cost, openhardware to design a system that met immediate needs andoffered the flexibility to expand the software and hardware in the future.

We used PXI hardware, including an NI PXI-8176 embeddedcontroller, 15 NI PXI-655x high-speed digital waveform generator/analyzers (300-channel capacity), and a programmable power supplyunit controlled via GPIB, for the solution. In addition to this hardware,we created the necessary mechanical fixture and unit under test(UUT) adapter board to interface with the 15 high-speed digitalmodules. With the built-in timing and synchronisation features ofPXI, we easily used multiple digital modules to achieve the high-channel count.

Software Modules for Existing Test Pattern Needs We created three powerful software modules (virtual instruments)to meet our demands for functionality and compatibility with existingtest patterns. The first was a LASAR translator module, whichautomatically translates output files from the LASAR simulationenvironment into the HWS standard, a format compatible with NI tools. The next module was the Go/No Go functional test modulethat can dynamically or step-by-step execute test procedures for the UUT. Finally, the reverse probing module we created guides the operation through the fault search and repair process when afailure occurs.

The LASAR translator module automatically converts existingtest information (simulator outputs) used on other digital automatedtest equipment to a format suitable for our DTS-LASET system. Themain objective of this module is to provide the manufacturer anduser with the ability to reuse the existing functionality of theirtraditional testers, particularly the reverse probing section, tominimise the cost of changing to a new digital test system.

The translation procedure contains the following key pieces: n Source file selection from the LASAR environment (*.tap file) n Generation of the translator configuration files n Generation of the test pattern (stimulus pattern and expected

pattern) in HWS format n Generation of the DUT database

Go/No Go Functional Test Module The Go/No Go functional test component controls the core digitaltest procedures, the generation of the stimulus pattern, andacquisition of the response data using NI PXI-655x digital waveformgenerator/analyzers. This module is also responsible for comparingthe acquired response data to the expected data. The stimulus dataand expected response patterns are derived from the outputs of the translator module.


Automated Test

EDA Industries Created a UUT Adapter BoardCapable of Interfacing With 15 High-Speed Digital Modules

EDA Industries SRL ni.com/aerospace 17

The Go/No Go sequence follows these basic steps: n Select the unit under test (UUT) n Test the UUT n Execute the test procedure n Display acquired response pattern and compare it to the

expected response

Reverse Probing Module When a failure is registered by the Go/No Go module, the reverseprobing module guides the user through the fault search and repairprocess. The module identifies the faulty component or wiring onthe UUT.

Using information from the board database and the pattern dataof the internal nodes (provided by the translator module), thealgorithm implemented in this module guides the user through thefault search procedure. An iterative algorithm is implemented thattraverses the electrical network of the UUT to identify thecomponent or wiring that generated the failure.

The Reverse Probing steps are: n Select the desired test options n Select the faulty line to debug and repair (if more than one) n Display probe instruction to guide the user n Test the current internal node

Digital Test System and LASAR Importer Solution We created a high-performance, low-cost digital test solution forSELEX Sistemi Integrati, a key European defense contractor, withNI software and hardware. We created the system without relyingon custom hardware or incurring the high cost of a general-purposetester. NI offered the necessary tools to create a digital test systemcompetitive with the traditional suppliers of automated digital testequipment. Our solution resulted in a 30 percent time savings and asignificantly better performance-to-cost ratio.

For more information, contact: Rabah DerradjiEDA Industries SRL 02015 Cittaducale (RI) Italy Tel: +39 0746 694044 Fax: +39 0746 694089 E-mail: [email protected]

Automated Test

Products:LabVIEWMotion Control

Adapting Ultrasonic, Nondestructive Pipe Testingto Gun Barrel TestingFBS developed its core knowledge and technical expertise for ultrasonictesting and system integration in the pipeline inspection industry. In thisfield, FBS was the first North American company to apply ultrasonicguided waves to long-range pipeline inspection. Using this technology,FBS could inspect hundreds of feet of pipe from a single location. Thisincludes underground pipe, tar-coated pipe, and product-filled pipe.

Because of the commercial success of this technology in thepipeline inspection industry, companies in other industries such as gun barrel inspection are adapting it to their applications.

The current U.S. military technology for gun barrel inspection ismainly limited to visual inspections. The U.S. Army rarely discardsbarrels because of visual defects but often disposes of them due to amandated usage limit. Limiting the number of times a soldier can usea barrel without an effective manner to predict failure, coupled withthe necessity for zero failures, results in the U.S. Army discardingmany useable barrels. Because the replacement cost of each barrel ishigh, and the Department of Defense is implementing a totalownership reduction strategy, the U.S. Army needed a rapid andaccurate barrel-testing system. The testing system had to:n Slide the instrument in and out of the breech effortlesslyn Provide real-time feedback on breech conditionsn Detect defects in accordance with the condemnation criteria for

120 mm cannon chamber sections per TM 9-1000-202-14n Adapt easily for bore inspection of several bore sizes

FBS applied its ultrasonic guided wave pipe inspection expertise tothe challenge of inspecting gun barrels from M1A1 Abrams tanks.

Designing an Instrumentation Systemfor Automated Breech InspectionWe developed an instrumentation system to quickly and accuratelyinspect the breech sections of M1A1 Abrams tank guns. We designedthe instrumentation system to be inserted into the chamber regionand perform an automated breech inspection. The device inspects thefull length of the breech by translating sensors along the barrel axis.

The advantages of this system include reduced error risk, quickerinspection speeds, detailed defect-depth information, and detection ofsubsurface defects. The U.S. Army readily can adapt the technologydeveloped thus far to inspect breech and smooth bore sections of

any geometry. Using this system, relatively untrained technicians can accurately detect threatening defects while saving money byextending the life of an average barrel. The prototype system built for the U.S. Army is called BLASST (BarreL ASSessment Technology).In the future, the U.S. Army can apply this type of inspectiontechnology to other military guns.

We built the system based on an industrial Pentium 4 3 GHz with768 MB RAM and the following data acquisition and control devices:n NI PCI-5102 dual-channel, 15 MHz, 20 MS/s 8-bit digitisern NI PCI-7334 motion controllern TB-1000 Matec toneburst pulser/receivern PC Instruments 8x1 multiplexer

We connected the devices to an array of ultrasonic transducerspositioned around the barrel circumference. In addition, we wrote the software completely in National Instruments LabVIEW. The maindesign elements included:n Intuitive design -- any technician can identify flaws.n Modular code -- we can reuse pieces of the code for any

similar projects.n Compatibility -- we can interface software with several

pulser/receivers, digitisers, motion controllers, and switches.n Integrated signal processing – technicians can take advantage

of filtering, averaging, and advanced processing.n Data storage -- technicians can save data to disk.n Real-time analysis -- technicians can make real-time

determinations on the viability of a barrel.

Inspect Tile Alternate Average.VI Front Panel

FBS, Inc.

Building an Ultrasonic, Nondestructive Test Systemfor the U.S. Army Using NI Modular Instrumentsand LabVIEWThomas Fina and Steven Owens – FBS, Inc.

THE CHALLENGEProviding the U.S. Army with a method to rapidly and accuratelyinspect the breech sections of M1A1 Abrams tank guns for geometrydefects and other degenerative flaws.

THE SOLUTIONCreating the system based on an industrial Pentium 4 3 GHzprocessor with 768 MB RAM using National Instruments high-speeddigitisers and motion control cards, and writing the softwarecompletely in the NI LabVIEW graphical development environment.


Automated Test

FBS, Inc. ni.com/aerospace 19

Saving Time and Money with FBS Expertiseand NI ToolsUsing NI software and hardware, we successfully created a system toinspect M1A1 Abrams tank gun barrels with guided wave ultrasonics.LabVIEW provided the necessary connectivity to several devices,including a third-party pulser/receiver and switch. The NI high-speeddigitiser gave us the performance and interoperability necessary tocomplete the application. Finally, NI test and measurement tools,coupled with guided-wave ultrasonic inspection expertise from FBSInc., kept development time short and costs low, as well as satisfied all U.S. Army system requirements.

For more information, contact:Steven OwensDirector of EngineeringFBS Inc.2134 Sandy DriveState College, PA 16803Tel: (814) 234-3437Fax: (814) 234-3457E-mail: [email protected]

“LabVIEW provided the necessary connectivity to severaldevices, including a third-party pulser/receiver and switch.”

Automated Test

Focus Software Inc.

Product:LabVIEW

Focus Software, Inc. and Sensor Developments Inc. teamed up todevelop an application that measures stress on an airplane propellerduring flight. Sensor Developments Inc. developed custom dataacquisition hardware that measures stress on a rotating propeller and transmits the data via GPIB back to the host laptop PC. FocusSoftware Inc. then used LabVIEW to develop software that configuresthe hardware, reads and decodes the GPIB samples using a PCMCIA-GPIB card, and uses a postprocessing utility to export data in ASCII or DaDisp-compatible formats.

Hardware DesignBecause of the uniqueness of the test, Sensor Developments Inc.designed and built custom signal conditioning and data acquisitionhardware, beginning with a rotating circuit assembly that digitizes the data from 32 strain gages attached to the propeller. Because the rotating system “pipelines” the data through existing deicing sliprings built into the aircraft engine, there is no telemetry requirement.Thus, it is easy to install the system rapidly on many different types of aircraft. The data from the rotating circuit passes through the slip rings to a stationary circuit that converts the data to GPIB format and transmits it to a laptop PC. The laptop runs LabVIEW and uses a PCMCIA-GPIB card to read the data stream. To make datatransmission as efficient as possible, the LabVIEW program receivesthe direct binary values from the 14-bit analog-to-digital converter(ADC) and later converts the data to engineering units.

Because these are in-flight tests, the team needed to design the tests with pilot safety in mind. We provided a simple remotependant control attached to the flight stick to give the pilot control over the test sequences. With the pendant control, the pilot can safely start and stop the test with the laptop monitor out of sight. The pendant also has a series of LEDs to inform the pilot of the teststatus, as well as any error status. The pendant control interfaces to a DAQCard-DIO-24 card.

Software Design ChallengesWhen designing the software, the biggest challenge Focus Softwarefaced was throughput speed on the GPIB bus. Overall, there are41 channels of data sampling at a rate of 6,000 S/s per channel.

We also use a 2-byte separator between each scan of data. Eachsample has 2 bytes of data, which means we need to read data at arate of 504 kbytes/s over the GPIB lines. The hardware uses a 32 KBoutput buffer, thus requiring the software to read the hardware at arate of more than 20 Hz. We found that streaming the data directly todisk on our laptop caused two problems:n The program ran too slowlyn The output buffer overflowed, with loss of data

For the first problem, we took advantage of the 192 MB of RAMin our laptop by storing all the data in memory until the end of the testand then writing it to disk. But moving more than 30 MB of data

(from a 60-second test) around in memory (with stringconcatenates and array builds) would slow the programdown significantly. To prevent this problem, we usedqueues, a new LabVIEW feature, with which you can store large amounts of data in RAM without usingmemory-intensive array or string operations.

To solve the second problem, we used anotherLabVIEW feature – multithreading. By running the GPIB

hardware calls in their own thread, we achieved the high speedsnecessary to get all data without hardware buffer overflows. Data filemanagement was another challenge we faced. Converting the rawdata bytes to ASCII or DaDisp format required us to convert the file in small sections. Reading and converting an entire 30 MB file inmemory took approximately five minutes with a Pentium II 266 MHzPC. Breaking the file into smaller pieces, however, reduced theconversion time to around 20 seconds.

ResultsThe system tests were very successful. The features of LabVIEWreally were a lifesaver in this application. Using multithreading andqueues, we quickly and efficiently read data from the GPIB hardware.Using the National Instruments PC cards, we housed this applicationin a laptop that fit behind the pilot’s seat. The PCMCIA-GPIB andDAQCard-DIO- 24 cards worked flawlessly.

For more information, contact:David DodgeFocus Software, Inc.6111 Jackson Road, Suite 117Ann Arbor, MI 48103Tel: (734) 994-1505Fax: (734) 994-1506E-mail: [email protected]

In-Flight Stress Testing of Airplane PropellersUsing LabVIEWDave Dodge – Focus Software Inc.

THE CHALLENGEMeasuring fixed-wing aircraft propeller stress during flight.

THE SOLUTIONBuilding a PC-based system using embedded strain gages, customconditioning and digitizing circuitry with a GPIB interface, and aPCMCIA-GPIB card controlled with LabVIEW.


“To solve this problem, we used queues, a new LabVIEWfeature, with which you can store large amounts of data in RAM without using memory-intensive array or stringoperations. To solve the second problem, we usedanother LabVIEW feature – multithreading.”

Automated Test

G Systems

Product:LabVIEW

A Flexible System Allowing Different Input SignalsOur company, Global Helicopter Technology, Inc. (GHTI), in Arlington,Texas, provides a variety of services for commercial helicopters, suchas upgrading, certifying, and supplying engine integration kits. Wework to characterise an aircraft’s physical behavior while in flight, by measuring quantities such as vibration, mechanical strains, andengine temperature. To improve its existing measurement system,We contracted G Systems to develop a new data acquisition systemusing National Instruments software and hardware. The Huey T53-703represents a typical of the type of helicopter that GHTI characterisesusing the new data acquisition system.

The system required flexibility for different types of input signals,acquisition rates, and hardware configurations. Normally, we cannotobtain all required measurements in a single test flight, so we must make multiple flights, each with a different measurementemphasis. An initial flight might focus on high-speed measurementsof vibration, while the second might monitor temperature, strains,and acceleration. The channel count can range from less than ten to several hundred, and acquisition rates may be as high as 20 kHz. Since helicopter space is at a premium, we had to make thehardware as compact as possible. Also, we the software had toproduce binary data files with a means of quickly reviewing dataafter a flight to verify data integrity.

Tests in the Air Controlled from the GroundTo accommodate high channel count and various signal types, weselected an SCXI system along with several stand-alone DAQ cards.We use a standard PC with a high-end CPU and ample RAM. Wechose LabVIEW as the development environment to easily build dataacquisition compatibility, file I/O, and analysis functionality into a singleapplication. The application detects the data acquisition cards and SCXImodules installed and updates the display accordingly. We can loadsaved channel configurations and create new configurations asneeded. The program notifies us if a previously saved configurationdoes not match the current set of hardware. We can enter scalinginformation, comments, and signal conditioning parameters throughthis single application.

In order to meet the space requirement, we do not use the monitorand keyboard during the flight test. Instead, we use a small, serial-based remote control unit to perform the basic functions of startingand stopping tests during flight. The unit also provides feedback aboutthe state of the acquisition, including current record number, errormessages, and remaining hard disk space. The controller has fourlines of 20 characters, 16 programmable function keys, and usesstandard RS232 protocol. We can custom label the function keys andprogram them to beep or send out a string when pressed. In this case,

we designated buttons to start and stop a test and request theremaining disk space.

When we finish setting up a test configuration, the applicationimmediately prepares for data acquisition. The application waits for amouse click on the GUI or for a button push from the controller tobegin acquiring data. If the computer reboots for any reason, itautomatically restarts the application, loads the last used configuration,and prepares for acquisition in the same way. The remote controlleralerts the user with a beep and a message when the application canbegin acquiring data again.

Real-Time Audio Synched with Transducer DataThe application produces binary data files to speed up file I/O andsave hard disk space while in flight. On the ground, we view the fileson the post analysis screen to verify that we can use the acquireddata. Then we import the files directly into a third-party program forfurther analysis. During flight, the application records data as rawvoltage or counts and converts it to engineering units (Hz, degrees F,or other) after the flight. We process data after the flight to allow allfor use of all resources to acquire data during the flight. Postponing all unnecessary computations until the test finishes, we can achievethe highest possible acquisition rates.

Normally, we designate one of the analog input channels for audioinput. We use this channel to record the pilot’s comments about themaneuvers he performs. Deciphering data during analysis is easiersince we can play back the audio in real time with the transducersignals. In the post-analysis screen, a cursor sweeps across the dataat the same time the audio plays back. The audio eventually convertsto a .WAV file so we can play back even without the LabVIEWapplication. We can record audio at any frequency, but sound qualitydegrades at frequencies below 8 kHz. The application interpolates thewaveform to bring it up to 8 kHz (or higher, if possible) in order tocreate a standard .WAV file.

We developed a highly configurable and easy-to-use data acquisitiontool using SCXI and LabVIEW to make measurements during helicopterflight. The system can accommodate any combination of availablehardware and is scalable to incorporate new hardware. A singleapplication provides conversion to engineering units, the ability toquickly review data, and audio playback. The methodology employedin this system provides GHTI with better data in less time thanpreviously achieved. The measurements derived from this systemprovides valuable information for characterizing and improving thecompany’s existing aircraft.

For more information, contact:Chris KoehlerG SystemsTel: (972) 516-2278E-mail: [email protected]

LabVIEW and SCXI Provide a ConfigurableMeasurement System for In-Flight HelicoptersChris Koehler – G Systems

THE CHALLENGEProviding a system to acquire data from a variable number of channelsand various types of transducers on a helicopter during flight.

THE SOLUTIONDeveloping a configurable LabVIEW application to acquire conditionedsignals from SCXI modules and other DAQ boards.

ni.com/aerospace 21

Automated Test

Products:Dynamic Signal AnalyzersLabVIEWMXIPXI/CompactPCI

Dramatically Reducing Test Cycle TimeAt G Systems Inc., we upgraded VME-based equipment with amore robust, compact, and reliable data acquisition and real-timecontrol system in less than four months. Lockheed Martinengineers now can configure their PXI-based system 10 timesfaster than their previous VME equipment while doubling theirchannel count. Also, the portable digital data acquisition system(PDDAS) reduces test cycle time from 2 s to 50 ms all for less than it would have cost to upgrade only a portion of the VME-basedtest system.

Improvements to jet engine designs require precise characterisationof engine operating parameters. To accomplish this, design engineersexamine the jet engine inlet air pressure profile to observe the air flowpattern distortions across the engine turbine inlet. To acquire this datarequires an accurately scaled model of the aircraft and a transonic windtunnel to simulate actual operating conditions.

Engineers at Lockheed Martin use scale models of equipment inthe testing of the F-35 Joint Strike Fighter. Because their previousVME-based test system proved too difficult to configure andupgrade, engineers at Lockheed Martin commissioned the newPDDAS system that we developed to control and acquire data fromtheir wind tunnel tests.

The PDDAS includes 128 channels of simultaneously sampleddynamic pressure measurements based on two PXI chassis,equipped with a total of 16 NI PXI-4472 dynamic signal acquisitionmodules. At first glance, two chassis may seem to unnecessarilycomplicate the system; however, by linking the two chassis usingthe NI MXI fiber-optic extension, no additional complexity wasintroduced. MXIbus basically performs as a PCI bridge to thesecond chassis. From a software point of view, the boards in thesecond PXI chassis appear as though they reside in the firstchassis. Using PXI also provides high enough data transfer rates(132 MB/s) at a competitive price for future expansion.

Also included in the PDDAS is the NI SCXI-1520, which connects to a full-bridge Kulite pressure transducer for strain gage signalconditioning. With LabVIEW Real-Time, we can achieve thedeterministic response time needed to both acquire air pressure data and to provide control signals back to the wind tunnel to varyoperating conditions.

Reflective MemoryWith The PXI architecture, we can handle the large data setsacquired in the PDDAS system, and LabVIEW Real-Time handleswhat is known as the “buzz” calculation (approximately 450,000floating point calculations per 50 ms), that looks for a resonancecondition in the engine inlet. At certain operating parameters, the air to the inlets may be in phase. If allowed to reach full resonance,the resulting forces can damage the engine. To prevent this, thePDDAS system constantly monitors for approaching buzz conditionsand provides feedback to the wind tunnel control system to changetunnel operating parameters as required.

G Systems

Lockheed Martin Reduces Costs and TimeTesting F-35 Joint Strike Fighter withLabVIEW Real-TimeDave Scheibenhoffer and Michael Fortenberry – G Systems

THE CHALLENGEReplacing a proprietary VME-based DSP system owned by LockheedMartin Aeronautics Co. with a system that acquires, analyzes, andstores dynamic pressure data from a next-generation jet fighter engine design.

THE SOLUTIONUsing industry-standard, off-the-shelf technologies including PXI, MXI, UDP, and RAID with LabVIEW Real-Time to create a tightlyintegrated data acquisition and control system that meets stringenttechnical demands.


The Portable Digital Data Acquisition System (PDDAS) incorporates bothLabVIEW Real-Time and PXI to control wind tunnel tests and acquire andrecord air pressure data from 128 different channels.

Automated Test

G Systems ni.com/aerospace 23

With the large data volume and computationally intensivecalculations, the embedded PXI-8176 Pentium controller does nothave enough remaining bandwidth to store all the acquired data to disk for permanent storage. To resolve this challenge, we used a VMIC reflective memory card in the PXI chassis. NI provided aLabVIEW Real-Time driver to support the setup and configuration ofthe reflective memory board. With this solution, we can “reflect”the acquired data to a Pentium host workstation running Windows2000. This workstation uses an off-the-shelf Fibre Channel board anddriver to write the data to a Redundant Array of Independent Disks(RAID) as a secondary task. Reflective memory proves a simple, yetelegant solution to resolve a potential system bottleneck.

System CommunicationBecause the PDDAS system is used at a number of wind tunnelsthroughout the country, Lockheed Martin engineers need aubiquitous mechanism to provide real-time feedback to theindividual wind tunnel control systems. Therefore, we used UserDatagram Protocol (UDP) for this application. Though UDP is not adeterministic protocol, it is a readily available interface at each windtunnel facility. By carefully selecting the LabVIEW task priorities, thePDDAS can send UDP packets at a deterministic rate of 50 ms.

For more information, contact:Dave ScheibenhofferG Systems Inc.Tel: (972) 516-2278Fax: (972) 424-2286E-mail: [email protected]

“With LabVIEW Real-Time, we can achieve the deterministicresponse time needed to both acquire air pressure dataand to provide control signals back to the wind tunnel tovary operating conditions.”

Automated Test

Product:LabVIEW 8.5

The application consisted of two components -- a DLL that calculatedthe value of Pi and a LabVIEW application that called the DLL libraryfunction and displayed the results in a GUI.

To calculate Pi, we used an approximate integration technique thatrequired the performance of several million floating-point calculationsin a loop. We chose this example because it was CPU-intensive, andwas a good candidate for the optimisation techniques we used. Thecode extract below shows the main loop in the external code, themajority of the CPU work being performed in the function CalcSum.

for (i=0; i<num_steps; i++)

sum = CalcSum(i, sum, step);

Our goal was to execute these calculations as quickly as possibleby using optimisation switches in the compiler.

The application had four functions, each in separate source files.We compiled each source file using different optimisation switches.Table 1 shows these.

“Plug and Play” with the Intel C++ CompilerWe used the Intel C++ compiler, a plug-and-play replacement for the Microsoft compiler, because we could easily integrate it into anexisting Microsoft Visual Studio DLL project. For more information on the Intel compiler, visit intel.com/software.

Default SettingsWe started our measuring with the application built with the /O2option. Many optimisations occur at this level. It is beyond the scopeof this document to detail them here. Table 2 shows the equivalentindividual optimisations that are incorporated in the /O2 option.

Auto-VectorisationAuto-vectorisation takes advantage of the sophisticated instructionsets incorporated in recent-generation CPUs. Most modern CPUshave architecture extensions to support data manipulation andmultiple data calculations. These extensions typically include supportfor implementing multiple calculations in a single instruction (singleinstruction multiple data, or SIMD). The Intel compiler is capable ofanalysing code and using these SIMD instructions, which can result in significantly faster code.

In the example here, we asked the compiler to generate codesuitable for a Core 2 architecture using the \QT option, and thecompiler reported the following build-time message:

remark: LOOP WAS VECTORIZED.

Looking at the disassembly of the generated code shows that thecompiler inserted some streaming SIMD extension (SSE) instructions.The use of these instructions makes an immediate positive impact onthe run-time performance of the application, with the code runningover twice as fast as the original code.

This type of optimisation is available on most current CPUs. We ranon a Core 2 processor, but this type of optimisation can also be usedon single-core and earlier-generation CPUs.

Auto-ParallelismBecause we had a multicore PC, we were interested in whether wecould get additional speedup by making part of the code run on bothcores using the \QParallel option. This option inserts a number oflibrary calls into a compiled object. These library calls provide thenecessary run-time control to make components of the application run in parallel.

Optimisation Description

/Og Global optimisations

/Oi- Inlining of intrinsic functions

/Os Speed optimisations

/Oy Omit frame pointers

/Ob2 Inline functions expansion -- at the compiler’s discretion

/GF Enable string pooling

/Gs Disable stack checking

/Gy Enable function-level linking

/Qftz Flush denormal results to zero

Table 2. List of Individual Optimisations Incorporated in the /O2 Option

Hitex UK Ltd.

Stephen Blair-Chappell, Technical Consulting Engineer --

Intel, UK, working in partnership with Hitex UK Ltd.

THE CHALLENGEOptimising handcrafted external code applications generated in NI LabVIEW software to take best advantage of the x86 architecture,and then measure DLL performance in the target system.

THE SOLUTIONUsing the Intel C++ compiler to achieve a speedup of 2.5 on a single-core PC and a speedup of more than 4.5 on a dual-core PCby using various optimisation switches in the compiler – not editingthe source code.

How to Build and Tune Multicore EnabledLabVIEW x86 Client DLLs


Automated Test

Function Option Description

CalcPi_O2 /O2 Calculates Pi using default settings

CalcPi_QT /O2 /QT Calculates Pi with auto-vectorisation

CalcPi_QParallel /O2 /QParallel Calculates Pi with auto-parallelisation

CalcPi_QT_QParallel /O2 /QT/QParallel Calculates Pi with auto-vectorisation and auto-parallelisation

lib_main /O2 Calls Pi functions and marshalls results

Table 1. Functions in the Application

Hitex UK Ltd. ni.com/aerospace 25

Automated Test

In our first attempt, the compiler did not apparently make anydifference to the run-time performance of the application. By turningon the reporting feature of the compiler, we saw that no optimisationhad occurred.

remark: loop was not parallelized: loop is not a

parallelization candidate

When the Intel compiler applies auto-parallelism to a section ofcode, it first determines whether there is sufficient “work” to becarried out to make parallelism worthwhile. In our code, there was a central loop that performed all the work. The compiler could notidentify how many times the loop would iterate -- the loop countervalue was passed in at run time. The compiler took a conservativeposition and declined to parallelise the loop.

The optimism of this heuristic can be modified via a command lineswitch /Qpar-threshold:n, where n is a number between 0 (alwaysparallelise) and 100 (never parallelise) that determines theaggressiveness of the heuristic.

After adding the option /Qpar-threshold:0, the compiler parallelisedthe code reporting:

remark: LOOP WAS AUTO-PARALLELIZED.

After we applied the optimisation, the application ran almost twiceas fast as the original default settings.

Other Optimisation OptionsIn this example, we focused on auto-vectorisation and auto-parallelisation. The Intel C++ compiler utilises a number of other optimisation techniques, including high-level optimisation, inter-procedural optimisation, profile-guided optimisation, speedoptimisation, code size optimisation, fast floating-point handling, and so on.

The Intel compiler also supports OpenMP, a pragma-basedstandard for implementing parallelism in application code.

Measuring PerformanceIn this example, we used the timing functions from the Win32 API andembedded the timing calculations in the external code. The calculationtime was displayed in the LabVIEW application GUI.

Alternatively, we could have used the timing facilities of LabVIEW,or used an external tool such as the Intel VTune Performance Analyzer.

VTune is capable of monitoring many different kinds of architecturalevents. The VTune Tuning Assistant can give further recommendations on how best to utilise these events.

The ResultsThe results of using the different optimisation switches are shown inTable 3. We ran the application on a dual-core PC and calculated thespeedup by using the default optimisation (/O2) as the base line.

We achieved a speedup of 2.5 by applying auto-vectorisation. This non-multicore-specific optimisation can be applied to mostmodern CPUs.

When we applied auto-parallelism, we achieved a speedup ofnearly 2. The combination of both optimisations gave us a speedup of 4.6.

The results here were achieved without having to edit the source code.

Although we chose a rather artificial application example(calculating Pi ), these optimisation techniques can be applied to real-life applications. Intel compiler users have regularly reportedsignificant code speedups when using such optimisations.

For more information, contact:

Stephen Blair-ChappellIntelE-mail: [email protected]

Dale FittesHi-TexTel: 02476 692066E-mail: [email protected]

Optimisation Time Taken (secs) Speedup

Default 0.938 1

Auto-vectorisation 0.375 2.5

Auto-parallelism 0.516 1.8

Auto-vectorisation and auto-parallelism 0.203 4.6

Table 3. Speedup Achieved with the Different Optimisations

Indonesian Aerospace

Products:LabVIEWDAQPad-1200

According to FAR 25.841 regulation, every aircraft designed to flymore than 8,000 ft high had to test the cabin pressure. Until nowexecution of these tests still used conventional methods. Conclusionof test results cannot be directly obtained with this method. Themeasured parameters need handwritten, manual calculations.

For simplification of the test procedure and increased accuracy oftest data, we have developed a test method using a computer anddata acquisition (DAQ) device. LabVIEW was used to automate thetest flow and data processing. This software application providesgraphic visualisation and conclusion of test results.

System Overview As mentioned before, the old test method with manual datacollection and analysis was not efficient. For this reasonperformance of tests depended on the operator. The operatorwould manage activity, record data, and control and monitor testsby hand during the overall process. The new test method offersinnovation for automated testing. We improved the test procedureby implementing a computer-controlled data gathering and analysissystem in one integrated system.

Goals of new innovation on test automation process: n Reduce investment cost of building test facility n Simplify test method n Automating test and control methods will increase performance

and accuracy of test n One place control system-monitoring capability n Minimise operator-read errors of test parameters n Automated generation of test result n Windows-based software control application n User friendly

Hardware Implementation The automatic leak test facility configuration consists of a computer,DAQ device, solenoid valve, air source, pressure transducer andtemperature transducer used in leak testing of pressurised cabins.This system measures leakage area levels of specially pressurisedaircraft cabins accurately, quickly and automatically. A computer andDAQ device are used to handle process control sequence tests andcollect data. A control mechanism controls the status valve at thevalue required and collects data from sensor. A four-channel DAQdevice is used in this leak test system. The channels are connected to sensor and solenoid valves placed within the package using a cable.

The testing process begins by compressing the cabin or unit undertest (UUT) with air until it reaches a certain value. Pressure andtemperature from the cabin environment are measured with a sensoror transducer. The transducer converts measurement values to currentor voltage.

Computer processes cabin pressure and temperature datacollection via transducer and DAQ device. When value of pressure oncabin has exceeded the limit from the permitted value, that solenoidvalve will control the flow rate of cabin pressure input. The blockschematic of the test system is shown in Figure 1.

Software Implementation The leak test system uses a DAQ device and is made fullycontrollable using virtual instruments (VI) for LabVIEW software.LabVIEW can command DAQ devices to read analog input signals(A/D conversion), generate analog output signals (D/A conversion),and read and write digital signals. The voltage data goes into theplug-in DAQ device on the computer, which send the data intomemory for storage and processing.

We developed the software using the graphical programmingenvironment of LabVIEW, ensuring the software is highly modularand has room for easy expansion. LabVIEW is hierachical, in that any virtual instrument can be quickly converted into a module whichcan be a sub-unit of another VI. We configured the total checkoutsoftware in a single virtual instrument that covers a systemcontroller, data acquisition, and data analysis and presentation. We integrated these seven VIs into the final main VI. With thegraphical user interface (GUI) of the main VI (shown in Figure 2) the user can visually monitor the process of the pressurised cabin leak test.

During test execution, the computer shows the main LabVIEW VI screen. This screen has several menus – User Identification,Parameter Setup and Output Waveform Graph. The screen indicatesGO if the test passed, and NO GO if the test failed.

New Innovation for Pressurized CabinFunctional Test on AircraftDanang Juliardi – Indonesian Aerospace

THE CHALLENGEReducing investment costs for an aircraft leak test facility with newinnovation test methods. The automation process control will increasetest result accuracy and data reliability.

THE SOLUTIONMaking integration process sequence tests with electronic devices. A computer will control mechanism of test. Test system developedfrom manual to fully automated method. Recording and processing of data test handled by computer tor maximal examination.


Figure 1. Block Schematic of Leak Test System

Automated Test

Indonesian Aerospace

Operation of software application testing is easy and simple. Firstyou must set up test equipment have as configuration of test. Next,initialise some parameter or variables such as pressure, temperature,cabin volume, permitted leakage area, and duration time of test, etc.You can execute testing after completing the configuration setting.The software functions are system control and data processing. Thesoftware also can control the status valve, read data sensors andprocess or analyse data collection.

For monitoring the status of tests on computer screen, the GUIshows three charts – ratio curve, reference curve, and result ofmeasure curve. Cabin leakage area value and conclusion of all testprocesses are also presented. The operator doesn’t need to write the results until the test is finished.

Printing a final test report from test result is simple. The user caneasily document test execution. Documentation of variables and testresult used for the test procedures is saved on disk. The data is savedin text format, which can then be opened with Excel or a text editor.

System Performance The VIs we developed for the automated checkout meet all of ourrequirements and have proven superior to the old test system in speed, cost, and compactness while meeting the accuracyrequirements of different functionality tests. Each VI gathers,scales, and compares the data to threshold values. GO or NO GOvalues provide controlled power-down in event of failure andprovides storage of results for the final test report. We illustratedthe comparison between the old test system and the VI-based new system in the table, above.

The main savings in time was achieved by sequentially carrying outthe control system configuration, data acquisition and presentation,and test report generation.

Conclusion Using custom-developed VIs we achieved a low-cost, virtualinstrumentation system by keeping the functionality high and pricerelatively low. LabVIEW was used as the key to significant benefits,providing both DAQ hardware integration in the facility test and testplan automation and documentation. The flexible and user-friendlygraphical programming environment of LabVIEW has considerablyreduced our system development time.

This study has also paved the way for development of a hardwareand software platform that can be easily modified, if necessary, toaccommodate any additional test requirements for this system, or to test similar systems.

For more information, contact:Danang Juliardi, EngineerIndonesian AerospaceGPM 6th Floor, Jl. Pajajaran No. 154,Bandung, 40174 Indonesia Tel: +62 22 6054010Fax: +62 22 6019538E-mail: [email protected]

Figure 2. Graphical User Interface and Results Window

ni.com/aerospace 27

Comparison Parameter Old Test Method New Test Method

System Cost$60,000 USD

€38,541; ¥6,271,800$400,000 USD

€256,937; ¥41,812,000

Compactness & Portability Low High

Automatic Test Report – 4

Table 1. Comparison Between the Old and the New Test System.

Automated Test

Lockheed Martin STS

LM-STAR NI Software-Based Test SystemSaves MillionsRobert Dixon – Lockheed Martin STS

THE CHALLENGEDelivering a test system for use in applications from manufacturing to environmental stress screening to depot testing on the more than3,000 planned Joint Strike Fighter aircraft.

THE SOLUTIONCreating a test system to deliver integrated support for avionics testsystems by using NI TestStand and LabWindows™/CVI for the coretest management and ANSI C test development environments.

Products:LabWindows/CVINI TestStand

In 2001, Lockheed Martin was awarded the largest aircraft contract in history. The Joint Strike Fighter (JSF)/F-35 contract, valued atapproximately $200 billion USD, provides the cornerstone of futuredefense capability for the United States and its allied partners. Acrucial part of the JSF contract is delivering a test system for use inapplications from manufacturing to environmental stress screening to depot testing on the more than 3,000 planned JSF aircraft.

To meet this challenge, Lockheed Martin Simulation, Training andSupport (LM STS) developed the LM-STAR test system to deliverintegrated support for avionics test systems. Designed to rapidlydevelop test solutions and support customers’ exact needs in a cost-effective and timely manner, the LM-STAR system uses NI TestStandand LabWindows/CVI software for the core test management and ANSI C test development environments.

Open Software Architecture Ensures Rapid Development In the LM-STAR system, an open software architecture basedlargely on NI TestStand and LabWindows/CVI supports theseamless transition of test systems from the factory to the field.The LM-STAR solution provides a common test system for allavionics suppliers participating in the JSF Harmonization Plan.

Essential for a project of the magnitude of the JSF program, the JSF Harmonization Plan allows multiple suppliers, including BAE Systems, Northrop Grumman, Rockwell Collins, and Raytheon, to simultaneously develop test program sets (TPS) using NI TestStand and LabWindows/CVI for the JSF/F-35. Theadvanced, open software architecture in the LM-STAR systemensures the rapid development and deployment of mission criticaltest systems while minimizing long-term maintenance efforts.

Test Software Adaptability Enables Multiple Test Configurations Using the standard features provided by the NI TestStand commercial,off-the-shelf (COTS) test management environment, LM STS testengineers built a common test architecture to facilitate the rapiddelivery of configurable test solutions. The key LM-STAR features use many core NI TestStand components, such as the flexible module adapters for calling tests developed in any test developmentenvironment and the NI TestStand process model for separating the core system functionality from the individual tests.

The LabWindows/CVI development environment also contributedto the rapid configuration of LM-STAR-based test systems byproviding industry-leading instrument connectivity and driversupport through a proven ANSI C-based development language and a compiler optimised for test.

Future Technology InsertionPrevents Obsolescence The modular test architecture of the LM-STAR system protectsmission-critical test systems fromobsolescence by using NI TestStandand LabWindows/CVI to ease theinsertion of future technologies.

One example is new NI TestStandsupport for calling ATLAS TPSsdirectly from NI TestStand. Thistechnology is important forsupporting legacy avionics testsystems through a common testarchitecture capable of hosting both

legacy and future test development environments. Specifically, thenew ATLAS interface for NI TestStand 3.0 features the ability tobrowse and select ATLAS TPS files, specify parameters, andperform remote control. Run-time features include full complianceof TPS Server state transitions, such as attaching, loading, anddetaching; parameter reading and writing; global locking; handling of manual TPS intervention; and the ability to pause and terminate sequence execution.

Avionics test system developers are also closely watching thedevelopment of the newly defined XML-based Automatic Test MarkupLanguage (ATML) standard for describing test procedures and testresults in XML. The open software architecture in the LM-STARsystem will significantly ease the adoption of this data schema foravionics test systems. In fact, NI has already demonstrated that thecurrent NI TestStand 3.0 XML features can generate results in thenew Test Results XML schema in accordance with the draft ATML specifications.

Standardised Approach Yields Significant CostSavings The innovative LM-STAR approach to standardised test systemdevelopment based on commercial, off-the-shelf test software has yielded many cost-saving benefits for LM STS, harmonisationsuppliers, and the U.S. government. LM STS estimates theirstandardised LM-STAR approach to the JSF/F-35 program hasalready saved the U.S. government millions of dollars and has the potential to save hundreds of millions more over the life of the program.

For more information, contact: Robert Dixon Lockheed Martin STS E-mail: [email protected]


The LM-STAR System Setup

Automated Test


MAC Panel Limited, United Kingdom ni.com/aerospace 29

“SCOUT” High-Performance, Short-WireMass Interconnect for PXIGary Clayton, Sales Director – MAC Panel Limited, United Kingdom

THE CHALLENGEProviding a modular system interconnection solution for PXI-basedATE systems that maximises the performance and modularitypotential of the PXI instrument configuration.

THE SOLUTIONUsing SCOUT from MAC Panel to provide the option of PCB, flex-circuit or short-wire connectivity. With a maximum wire length of 110 mm, SCOUT provides a consistently uniform, reliable high-performance connection without the cable management issuesassociated with traditional mass interconnect designs.

Products:Available for use on all National Instruments PXI chassis.

The customer, a major global medical equipment manufacturer,wanted to develop a new test system platform based on PXIarchitecture. Historically they had used VXI instrumentation with a“pull thru” mass interconnect from MAC Panel. The advantages of a pull thru interconnection is that higher electrical signal integrity can be achieved and maintained, while system wiring costs are greatlyreduced; the best of both worlds! It was essential that the chosenmass interconnect would yield the same benefits as the previousgeneration of testers. Although this solution was developed for themedical industry, the benefits realised are applicable to any industrysector where signal integrity is very important – this especially true in avionics and military applications.

The PXI platform would enhance system modularity andreconfigurability to more easily manage future needs. Also, sinceeventually testers would be deployed globally, it was important thatindividual testers could be configured with the correct instruments for a specific local need.

The chosen configuration of the tester was based on a variety of general-purpose PXI instrumentation and switching from National Instruments. The mass interconnect was SCOUT from the MAC Panel Company.

The new MAC Panel SCOUT is a configurable mass interconnectsystem that provides a PCB or short-wire interconnection for your PXI-based test system.

Each PXI instrument is attached to a receiver connector module via a direct access kit (DAK) adaptor, providing direct connectivitybetween the PXI instruments and the SCOUT receiver. All instrumentsare easily installed or removed through the front of the receiver,without disturbing the system wiring. DAK adapters utilise standardMAC Panel L2000 Series connector modules, providing a wide varietyof contact types: with signal, power, coax, RF and hybrid combinationsavailable. The connection between the PXI instrument and receivermodule is accomplished using either printed circuit boards or flexcircuits, providing optimum connectivity performance while reducingwiring cost. Where a wired solution is preferred, the DAK adapterprovides for a short wire alternative to traditional hinged massinterconnect receiver designs.

The SCOUT mass interconnect system is ideally suited to gainmaximum benefit from high density PXI switch modules. By utilizingPCB, flex-circuit and short-wire connectivity techniques between thePXI instruments and the SCOUT receiver, unprecedented wiringdensities can be achieved without the cable mass normally associatedwith ATE system wiring.

SCOUT receivers are available in a variety of configurations to suitall National Instruments PXI chassis. Preterminated DAK assembliesare available for all PXI instruments. Alternatively, DAKs can easily becustomer-configured to suit specific application requirements.

With several testers now deployed around the world, the move toPXI is deemed to have been a success, having met or exceeded all the specified technical and budgetary objectives.

More detail on the SCOUT mass interconnect system,along withlocal contact details can be found on our Web site at macpanel.com.

Figure 2. NI PXI-1042 Chassis with 11-Slot SCOUT Receiver AttachedShowing a PCB DAK Assembly

Figure 1. SCOUT DAK (Direct Access Kit) Showing PXI Instrument Attached

Automated Test

Mantech Test Systems

Product:PXI/CompactPCI

In 2002, the U.S. Air Force awarded ManTech Test Systems amultimillion dollar contract for development, production, and supportof test equipment for LANTIRN systems. LANTIRN, or Low AltitudeNavigations and Targeting Infrared for Night, is a system used on U.S. Air Force premier fighter aircraft, including the F-15E Eagle and F-16 C/D Fighting Falcon. LANTIRN significantly increases the combateffectiveness of these aircraft, allowing them to fly at low altitudes, at night, and under the weather to attack ground targets with a varietyof precision-guided and unguided weapons.

Using PC-Based Software and Hardwareto Lower CostsThe contract charged ManTech with updating LANTIRN testsystems that will be fielded at 19 Air Force locations around theworld. The original LANTIRN test system dates back to the late1980s, and was based on MicroVAX computers tied to stand-aloneinstrumentation. Not only was the system large, requiring sevencomplete racks of space, but the Air Force faced a host of reliabilityand maintenance problems from the growing obsolescence of testsystem components. In many cases, the Air Force had to reverseengineer and redesign obsolete components on the original teststation. As a result of this problem, the Air Force specified andbudgeted for a new test system in 2002. A major requirement of the new system was to take advantage of new commercial off-the-shelf (COTS) technology, such as industry-standard, PC-based hardware and software, to reduce the size and cost of the new test system. By specifying off-the-shelf components,the military is able to search across all industries for powerful and low-cost components that are relatively easy to replace and upgrade.

Reducing Test System Size by 50 PercentManTech selected PXI for a portion of the test system, largelybecause PXI provides the advantages of COTS technology, while still meeting the needs of military specifications in test programs. For example, the specification required extended operating andnonoperating environmental conditions, which National Instrumentsmet with the new NI PXI-8186 Intel Pentium 4-based PXI embeddedcontroller. This provided ManTech with the performance and costbenefits of the latest off-the-shelf processors from Intel, while alsomeeting the military specifications for environmental conditions of the test system. Additionally, the replacement of the obsoleteMicroVax hardware with PXI and other systems dramatically increase the mission-ready time of the test system.

ManTech was also able to reduce the size of the test system fromseven racks to three, a more than 50 percent reduction due in largepart to the incorporation of PXI instrumentation, which includes up to17 PXI instruments in just 4U of rack space.

Commenting on the Air Force’s award of the contract to ManTech,Peter D. Faulkner, vice president of government programs forManTech Test Systems, said, “Our solution takes advantage of themany technological advances that have occurred in the automatic testindustry since the LANTIRN support equipment was originally placedin service. The Air Force can expect a tremendous improvement inmission capable rates in a system that is less than half the size.”

LANTIRN System on an F-16 on the Flight Line

U.S. Air Force Increases Mission-CapableRates with PXIJohn Abdale – Mantech Test Systems

THE CHALLENGEDeveloping, producing, and supporting test equipment for LANTIRNsystems on U.S. Air Force premier fighter aircrafts.

THE SOLUTIONUsing NI PC-based software and hardware to lower costs and reducesize of test systems by 50 percent.


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Automated Test

Mink Hollow Systems, Sigma Space, Global Science and Technology/NASA-Goddard Space Flight Center

NASA uses NI LabVIEW to Save Time, ReduceCosts in Automated Testing of MicroshuttersDavid McAndrew – Mink Hollow Systems,

David Mostofi – Sigma Space,

David Rapchun – Global Science and Technology/

NASA-Goddard Space Flight Center

THE CHALLENGEDeveloping a flexible test application that can actuate tens ofthousands of micron-sized shutter elements (microshutters) formillions of cycles while logging data, acquiring high-resolutionimages, and monitoring and controlling the test environment.

THE SOLUTIONUsing a National Instruments application based on LabVIEW so the user can configure and run custom shutter actuation testswhile monitoring and controlling the test environment.

Role of Microshutter Arrays for theJames Webb Space Telescope As the Hubble Space Telescope nears its twilight, our appetite forspace exploration has only intensified. The James Webb SpaceTelescope (JWST) is our next stepping-stone toward understandingthe universe and studying the Big Bang theory. With these lofty goalscome intense challenges: development of new, lightweight materialsfor larger apertures; improved detector technology for faint signals;and microshutter arrays for sensing hundreds of simultaneous spectra.

Using LabVIEW to test microshutter arrays, we can detect anddiagnose problems early in development and greatly reduce overall cost.

The need for microshutters in the near infrared spectrometer(NIRSpec) came from the following mission constraints: n A single spectral measurement can take days, making the

need for a multisensing device critical. n Without an aperture mask, spectral overlap contaminates

data sets, resulting in unusable data. n The mask must be configurable to change with the motion

of the satellite.

From these constraints, NASA Goddard Space Flight Centerdeveloped programmable aperture masks (microshutters) to meet the JWST mission goals.

Operation of a Microshutter Array A microshutter array consists of tens of thousands of 100 µm x 200 µm shutter elements that can be individually held open or closedto create a custom image mask based on the sensor field of view.In operation, elements are opened where objects exist and closedwhere interference between objects would occur on the detector.

Sweeping a magnet across the array pulls the shutters open. By applying a voltage to the appropriate row and column of the array,an individual shutter can be held open after the magnet passes. Non-powered shutters will close.

Incorporating Tester Hardware The goals of the microshutter tester are twofold: 1) provide designfeedback and 2) estimate unit life. Because the testing environment

must mimic the conditions of space, the software delivers systemmonitoring and control of temperature and pressure using GPIBinstrumentation. With this control, users can subject units to varioustemperature profiles that simulate the effects of solar warming.

To provide design feedback and estimate unit life, the automatedtester actuates shutter elements repeatedly while capturing images at specific intervals. A GPIB power supply and digitally driven relayssupply power to the arrays. NI PCI-7344 controllers and NI MID-7604drivers control magnet motion and three-axis camera positioning forimages taken during testing. If the user finds a problem, they can putthe system into a higher-resolution “image-mosaic” mode that scans a camera with 4-micron resolution, yielding more detailed data ofindividual shutters. Users stitch together individual images are usingMink Hollow Systems MosaicVIEW software.

Progressing Technology through Flexible Test We created modular test software to configure custom tests and addor change instruments with minimal code changes. Duplicate testfixtures in the controlled environment required the software tosimultaneously run two tests. Incorporating many different instrumentsand maintaining modular code made LabVIEW an obvious choice forour development language.

A test procedure is a list of commands sent to the tester whereeach command is a predefined function. With the use of procedures,users can configure new tests without code changes.

ni.com/aerospace 31

Microshutter Tester GUI

Products:NI Data AcquisitionLabVIEW

Motion ControlVision

Automated Test

For example, a test procedure to cycle an array with imaging may be created as: n Power microshutter elements n Sweep magnet across array (all shutters open) n Capture image n Remove power from microshutter array (all shutters close) n Capture image

Users can compare this test to a test where the magnet is sweptacross the array before the last image is captured. The results yieldinsight into the spring force on the elements if they intermittentlystay closed without an additional magnet sweep.

Test cycles with imaging require significantly more time than acycle without imaging. To perform a test that cycles millions of timesbut still acquires images, we designed the system to allow two testprocedures. These two cycling procedures combine in a test scriptthat lists the number of magnet cycles to complete before running theimaging procedure. With this capability, the user can create tests thattake more images at the beginning of a test and fewer as the testprogresses, providing both increased test speed and image feedback.

This is a vital feature because early testing of microshuttersrevealed that shutter failure probability decreases as the number of actuations increases.

To accommodate changes to the test station, instrument driversare implemented as objects for easy device-type addition. Forexample, in the next-generation tester, a QImaging camera isreplaced with a Sony. Despite differences in drivers, the softwareincludes an imaging object where the methods and propertiesremain the same but the underlying code is product specific.

With this design, we achieve seamless integration of the newcamera while maintaining a single version of the overall software and,most importantly, we eliminate the need for updating test procedures.

Saving Time, Reducing Costs The NIRSpec with microshutter arrays gives scientists the capabilityof simultaneously acquiring hundreds of spectra from the JamesWebb Space Telescope – a first in space-based astronomy. This newtechnology promises datasets unimaginable with today’s sensors butrequires proven lifetime longevity. Our automated tester helps studythe performance and verify the feasibility of the microshutters bygiving users the freedom to perform custom tests and rapidly adapt tonew test instrumentation and with minimal effort. Using LabVIEW, wecompleted the modular test software quickly, which gave us time todetect and diagnose problems early in development, greatly reducingoverall costs.

For more information, contact:David McAndrewTest EngineerMink Hollow Systems6880 Mink Hollow Rd. Highland, MD 20777 Tel: (301) 854-1579 Fax: (301) 854-9756 E-mail: [email protected]


Figure 2. NASA Microshutter Control Block Diagram

Automated Test

Mink Hollow Systems, Sigma Space, Global Science and Technology/NASA-Goddard Space Flight Center

Development of an In-Engine Turbine Traverse SystemBernard Killeen, Systems Engineer – Richmond Measurement Services, Derby, England

THE CHALLENGEMeasuring aerodynamic data across the high-pressure turbine gas stream during jet engine performance testing.

THE SOLUTIONDesigning and manufacturing a bespoke engine-mountinginstrumentation enclosure fitted with a novel platinum tippedaerodynamic probe.

Jet engine design makes extensive use of CAD modelling. Thesemodels are highly sophisticated but they are far from perfect. To verifythe computer modelling, it is necessary to correlate the models withtests carried out on real engines. This is an essential part of thedevelopment process.

Turbine test correlation has always been difficult due to theexcessive temperatures and pressures of the gas stream. Traditionally,test models run at lower temperatures and pressures than the realturbine, and the results are scaled. This process has limitationsbecause of tip and hub boundary conditions, tip leakage, and scalingerrors due to the increased temperature and pressure.

Richmond Measurement Services (RMS) needed to measuregas conditions at four locations within the turbine area of a full size development Rolls-Royce Trent 900 jet engine. The testinstrumentation was designed to measure total pressure, staticpressure, flow velocity, and flow direction.

The test system consists of a bespoke aerodynamic probe, aninstrumentation enclosure, a 19 in. rack-mounting electronics unit, andbespoke PC software for motion control and data acquisition written inMicrosoft Visual Basic 6.0 and incorporating NI-Motion, NI-DAQmx,and NI Measurement Studio software. We combined the PXI-basedelectronics rack mounted above the engine with special-purpose high-temperature cabling to ensure data integrity. Then we connected atest cell PC system to the PXI chassis with a fibre-optic cable to allowoperator interface and test control.

Test VehicleFigure 1 shows the test engine during the performance test. Turbineentry gas conditions are up to 1,700 K at up to 250 psi. Outside theturbine casing, the temperature reaches 250 °C, and is an ATEXZone 2 hazardous area.

The engine hangs from a pylon structure that represents theairframe. There is space for hardware above the pylon, but this area is not accessible during engine testing. Cable routing from the pylon to the test cell control room is awkward, and lengthy runs can be anticipated. Electrical noise levels within the test cellare potentially significant.

PrinciplesRMS has considerable experience in providing bespoke instrumentationsystems for use in aero testing environments. Where practical andpossible in the design of this system, we wanted to reuse thisexperience and incorporate off-the-shelf hardware, which has a proventrack record as well as a technical support structure.

In general, we recommend providing signal conditioning as closeto the sensor as practical, which meant that electronic systems were going to be located on the engine and in the test cell. We alsowanted the system to be modular and expandable to cope withflexible specifications.

ProbeA probe that passes through the turbine casing into the gas streammeasures the gas temperature and pressure. The probe tip wasmanufactured from a platinum alloy and welded to a stainless steelsupport tube. The support tube is cooled by flowing water down to the probe tip. At the tip, there are pressure sensing ports and a thermocouple. Outside the turbine casing, there is a mechanismto manipulate the probe as well as pressure sensors andthermocouple electronics.

Richmond Measurement Services ni.com/aerospace 33

Figure 1. Test Engine During the Performance Test

Figure 2. Platinum Probe Tip

Products:M Series Data Acquisition PXI-7358 Motion ControlPXI-1042 ChassisPXI-8336 MXI-4 InterfaceMID7604 Motor Drives

MXI-4 Fiber-Optic Cable, 200 mMeasurement StudioNI-DAQmxMotion Driver Software

Automated Test

Richmond Measurement Services

Instrumentation EnclosureThe instrumentation enclosure is a self-contained unit that features a probe manipulator, pressure sensors, and thermocouple signalconditioning unit. The internal temperature is maintained below 70 °Cby combined air and water cooling systems. The unit also providesprobe water cooling. Spare sensor channels are used for healthmonitoring. Four enclosures were mounted around the turbine casing.

Control and Data CablesEach enclosure is serviced with air, water, and electrical systems. The electrical cables were specified to withstand 250 °C. Two cableswere designed, one for the manipulator that carries motor andencoder signals and the second cable for analogue signals. The cables were routed around the engine and up through the supportpylon to a rack system located above the pylon.

Pylon RackThe pylon rack contained a National Instruments PXI chassis fittedwith data acquisition and motion control systems. Additionally, therack contained two multichannel stepper motor drives and a dataacquisition interface unit to allow electrical system interconnection.The unit also contained a UPS to maintain system power in the eventof main power failure. We also used the PXI chassis to monitor the airand water cooling systems.

Test Cell PCThe PC system, located in the control room, communicates with thepylon PXI chassis using MXI and fibre-optic link. The PC was also fittedwith an additional data acquisition board to monitor signals availablewithin the test cell.

We used the Windows XP Professional OS and wrote bespokesoftware in Visual Basic using NI-DAQmx, NI-Motion, andMeasurement Studio software.

The PC is powered by a UPS so that the entire system will continueto function for at least half an hour in the event of mains power failure.

Traverse SoftwareThe traverse software module is responsible for moving the probe within the gas stream. This module communicates with the NI PXI-7358 stepper/servo controller fitted to the pylon PXI chassis.

The PXI-7358 runs an onboard program that can retract the probes to a safe location if the host PC fails for any reason.

Data Acquisition SoftwareThe data acquisition software module has a series of screens that an operator can switch on or off as needed. This means that the operator can concentrate on the data of interest withoutdistraction. The remaining information is essential for setup andtroubleshooting purposes.

This module is also responsible for recording data to disc. The software records data to a set of data files, which allows forimmediate access to engineering data that can influence the testschedule, but it also allows for subsequent analysis to any depth.

CalibrationThe manufacturer’s calibration was used throughout. During benchtesting, the system was audited by applying calibrated signals to thesensors and checking that recorded data is within specification.

ConclusionThe traverse systems performed as expected during the engineperformance running. Data was collected efficiently and effectively.The client was delighted with the quality of recorded data and theperformance test program was altered following a review of the firstdata sets. In total, six performance runs were recorded covering morethan 100 hours running.

The author wishes to acknowledge the assistance of JamesAnderson of QinetiQ, of Farnborough, in the preparation of this case study.

Figure 4. PC System in the Control Room


Figure 3. Instrumentation Enclosure Mounted on Turbine Casing

Automated Test

SCITEK Consultants Ltd, UK

Products:NI DAQNI LabVIEWLabVIEW Real-Time

SCITEK Consultants provides research and development services to high-technology companies requiring industry ready solutions from novel ideas. We specialise in providing control systems andinstrumented rig solutions for R&D applications. As part of our recentexpansion we have created and run a gas turbine engine facility thatcan be used in a variety of development applications. Typical uses ofthis facility have included development testing of instrumentation formeasuring soot and NOx emissions, turbine blade tip clearanceprobes, pressure measurement at high temperatures, and for thedevelopment of high temperature noise sensors.

The engine facility has been used extensively over the last sixmonths for evaluating and comparing different novel sensor designs in a harsh and repeatable environment. We have used the versatilityof the National Instruments instrumentation platform to provide a comprehensive set of supporting measurements. Our extrainstrumentation has provided our customers with valuable information to help them evaluate their results.

The engine facility has been used to evaluate a number ofinnovative noise sensors from different companies. The varioustechnologies were assessed for accuracy and durability at high-temperature locations close to, or at the turbine disc of the engine.Results from optical noise sensors compared with traditional rumbleprobe sensors are shown in Figure 2.

These results show the blade passage frequencies and associatedharmonics which vary with engine speed. All three plots showdiffering characteristics that were not apparent from the tests carried out in the benign environment of the laboratory.

The jet engine facility provided the realistic operating conditions that brought out the abilities and deficiencies of sensor performance.While testing a sensor’s primary function, differing temperature,pressure, vibration or other effects are rarely simulated simultaneouslyin the laboratory environment. SCITEK’s Viper test bed is a genuinetest environment that can give an early indication of technologies with promise of an early entry-into-service and those that require significant development.

Another example of the jet engine test bed’s use is that ofdeveloping sensors to measure the clearance between turbine bladetip and shroud seal at the rear (hot end) of the engine. Minimising thetip clearance is of vital importance to improving engine efficiency byreducing energy losses. It is known though modelling that thecomplex geometries and material characteristics at this end of theengine dictate that the clearances will not be at their best for themajority of the flight. But, if it were possible to measure the tip

Figure 1. Viper Test Bed

Viper Jet Engine Test Bed: Delivering Flexibilityand Reliability through an Integrated Hardwareand Software Data-Gathering Platform Marios Christodoulou and Jon Bates – SCITEK Consultants Ltd, UK

THE CHALLENGEProviding a cost-effective gas turbine engine test bed that can be easily instrumented to test a variety of novel aerospace sensor technologies.

THE SOLUTIONCreating a realistic test environment for appraising developmentalaerospace sensors using a Rolls-Royce Viper 201 jet engine. Wechose National Instruments hardware and software to provide theinstrumentation platform to meet the ever-changing data acquisitionrequirements of the various projects.

ni.com/aerospace 35

Figure 2. Three sensors measure jet pipe noise. Blade passage tonesare clearly seen, but other tones are picked up, showing variability onthe sensor characteristics.

All results by kind permission from Oxsensis Ltd

Figure 3. Modified Turbine Seal Ring

Automated Test

clearance there would be a chance to rectify the situation using active control.

In the Viper engine, a stationary sensor will see up to 26,000turbine blades per second at temperatures up to 750 °C. As this isclose to the extremes that they will be subjected to in operationalservice in modern engines, the Viper is an ideal test bed. We modifiedthe seal ring on our Viper to accept development probes of varyingdimensions and ran back-to-back tests with each development sensoralongside a “datum” sensor.

Results from one of the tip clearance probes are shown in Figure 4,and demonstrate how the clearance between turbine blades and sealvary with engine operating conditions. Changes in turbine blade tipclearance are a very demanding and complex phenomenon to studyand it has a large impact on the fuel efficiency of a gas turbine engine.

Tip clearance is affected by engine speed, temperature, pressureand heat transfer characteristics of materials that all contribute to howthe gap varies under a variety of operating conditions and accuratemeasurements are key to optimising the design solution.

Conclusion The main challenge was to establish a facility that could be run safely,reliably and produce accurate and meaningful results in a wide rangeof situations. The Rolls-Royce Viper201 engine was chosen for itsability to recreate conditions that are relevant to modern large gasturbine engines and for the ease with which it could be modified toaccommodate varying measurement requirements.

The engine control and instrumentation system is based onNational Instruments hardware and LabVIEW software as we neededaccuracy, reliability and the ability to react to changing requirements on short notice.

SCITEK Consultants Ltd, UKMilitary/Aerospace Case Studies36

Figure 4. Variation of Tip Clearance with Engine Speed for Three Rapid Acceleration andDeceleration Cycles

Automated Test

Robin Lord, BEng Hons.and Nick Martin, BSc Hons. MIEE –

Serco Test Systems

THE CHALLENGESupplying a compact COTS-based test solution to burn-in amilitary avionics system.

THE SOLUTIONDesigning and building a burn-in test set by implementingNI TestStand.

Product:NI TestStand

The Objectives and Strategy of the Burn-In Test At Serco Test Systems, we needed to develop a burn-in test systemcapable of inducing time and stress-dependent failure of defectivecomponents during manufacturing to prevent early mortality problemsoccurring in the field. Initially, the failure rate is high because ofinherent or manufacturing-related defects. A period of low defectsfollows, until the failure rate rises as the product nears the end of itsoperational life. The burn-in process is a repeated cyclical application ofthermal stresses and functional electrical tests. We load units undertest (UUT) into a thermal chamber and connect these units to testequipment. Cyclical testing commences during the heating cycle andpauses when the chamber cools with UUT power removed.

NI TestStand Meeting the Challenge Avionics requires burn-in testing to detect problems only exhibited attemperate extremes. Burn-in test cycles are long in duration andrequire repetitive testing, which can present problems to the testsolution provider. Serco Test Systems can use NI TestStand tosuccessfully address these challenges: n Ensuring units under test are not over-stressed during burn-in

testing phase, which performs sufficient testing across thetemperature range

n Providing multiple unit test in parallel, thus maximizing chambertime and production throughput

n Catering for the ability to cancel a single unit withoutcompromising ongoing testing

NI TestStand Sequential Process Model We divided the default NI TestStand sequential model into two blocks – the automated test procedure (ATP), containing user-defineddiscrete test steps; and the sequential process model (SPM) wrapper.The wrapper handles standard operations for each product tested,including test start/stop, result collection, and test report creation. Weefficiently transfer control between the wrapper and user-defined ATP.We designed the SPM to test one UUT once and then move to thenext phase. Avionics burn-in requires several test cycles on the sameUUT and multiple units under test in a single chamber. Therefore, theoptimum solution is to modify the SPM to create a burn-in processmodel (BPM).

Avionics Burn-In Test To maximise chamber use, it may contain differing UUT types. Wehave developed the BPM to cater for multiple UUT types by allowingusers to determine the ATP sequences at the run¬time phase.

Pre-UUT Steps In the first stage of the testing loop, we set variables to control ATPflow. Test-type and cycle status indicators are set to “pretemperature”and “cold”, respectively. A UUT data entry panel displays – theappearance depends on the UUT type. With this panel, the operator can provide details for each UUT of that type. This enhances throughputwhere multiple or different units under test are in the same chamber. A status panel loads following the initialisation of each UUT. Thisdisplays the UUT’s location and ATP type for execution.

A numbered square represents each UUT. These units are colorcoded according to the current state in program execution. Operatorscan select the “Amend Details” button to change previously enteredinformation. This facilitates loading and unloading the units under testduring the testing phase to maximise chamber usage.

Main SequenceBurn-In ATP Initialisation of instruments andconnection instructions to theoperator, both tailored to UUTtype for a newly loaded UUT.

Pre-Temperature Tests Tests executed for each UUTensure all test subjects areoperational prior to thermalcycling. In the event of UUTfailure, the system offers areplacement option. The test system initalises reports for each UUT upon successful completion.

Hot-Cycle Temperature TestsWhen the chamber status enters a hot cycle, the sequence updates“test type” to “Temperature” testing and calls the ATP main sequence.This executes full testing for each UUT by compiling individual reports,displaying the status panel, and monitoring the chamber.

Cold Cycle – Test Pause When the chamber status enters a cold cycle, it removes power fromall units, and the sequence returns to pre-UUT phase, updating thestatus panel and monitoring the chamber.

Test Termination To avoid terminating a complete test cycle because of an individualUUT failure, the BPM includes two differing termination functions.

Serco Test Systems ni.com/aerospace 37

Implementing an NI TestStand Process Modelfor Avionics Burn-In Testing

Figure 1. Serco’s Burn-In Test Set

Automated Test

Serco Test Systems

During pretemperature or hot-cycle testing, the operator may select“Terminate Current UUT”. The sequence exits the ATP and returns to the “Handle Termination” subroutine. This removes power of theselected UUT. The BPM then alters control variables to discontinuetesting of that UUT position in future test cycles and inserts resultsinto a report. The operator also can select “Terminate ALL”. Thisimmediately powers down all units under test, completes reports, and concludes the test.

Testing Complete The cyclical testing continues until the test type is set to “Complete”. This can occur in the following ways: n Testing completes the number of chamber cycles n During testing, the power supply fails, forcing the sequence

to exitn The sequence is terminated

This BPM has been successfully applied to numerous avionicsburn-in variants with up to 16 test subjects and four UUT variants.

Developing a Flexible Solution Modifying the SPM addresses complex test sequence problems. By combining this module with the latest NI TestStand features, we can achieve a unique, flexible solution for all test requirements.

For more information on implementing NI TestStand or other testchallenges, contact Serco Test Systems at sts.serco.com.


Figure 2. The Operator Interface Status PanelHandles up to 16 Different UUT Types

Automated Test

Notes ni.com/aerospace 39

Automated Test

Military/Aerospace Case Studies40 Notes


Products:LabVIEWPXI/CompactPCI

At Aegis Group, we provide multifunctional services includingembedded and enterprise software development, mechanicalengineering, electrical engineering, and industrial design. Our client,a major aerospace agency, approached us for help updating threemajor communications subsystems. These systems employed 19 replaceable VME-based cards, most of which were designed and built using technology from the 1980s. The number of properlyfunctioning cards had dwindled to critical levels, but it was not cost-effective to build new cards, so the aerospace agency had torepair the existing cards. However, when individual cards failed,troubleshooting the problems was an overwhelming task, so a new approach was imperative.

The agency required a system that would efficiently identify bothfaulty cards and failed components on the cards. This system neededto be easy-to-use for nontechnical personnel, had to quickly andaccurately diagnose cards down to the component level, be scalableto add new functionality, and needed to last through 2015. Weapproached this project understanding that we needed to develop a testing solution that was innovative and comprehensive.

The Hardware SetupOur solution included seven power supplies, each of which provideddifferent voltage outputs as well as separate power for the card beingtested and the custom-built, extended test circuit (ETC) board. TheETC board communicated via VXI, and the printed circuit boards(PCBs) under test used VME, which we simulated on the ETC. The ETC board also included two field-programmable gate arrays(FPGAs), which simulated a VME backplane and allowed for custommessages and error injection.

The test system also used an oscilloscope to capture and displaysignals. An NI VXI controller provided interfaces between the PC and the ETC board, the power supplies, and the oscilloscope.

We designed a mechanical linkage that contained all moving partsworking in concert for easy insertion and removal of PCBs and customadapter cards without damaging or stressing their high-densityconnectors. The custom test fixture consisted of an ergonomic testcradle, commercially available and custom electronic components,custom connections, and custom cabling.

The hardware fixture was designed for both maximum functionalityand ease of use. For each card, it needed to simulate the operatingconditions, offer quick access to all sides, and be fully configurable for different card requirements.

The Software SetupNI LabVIEW software provided the foundation for each card’s rapidtest component development, self-diagnostics for the customelectronics components, and flexibility to build in expandability andcustomizability. LabVIEW seamlessly integrated with the NI hardwareused in the system as well as communication with third-party devices.With LabVIEW, we developed a user interface that displayed graphicsand text during each test, the resulting signal waveforms, and ahierarchy of tests for each card. There were easy-to-use instructions,images, and graphics for correctly inserting and connecting each card,including any special cables. When we tested signals, a displayshowed the component and pin that we probed during the test. Wealso designed and created a custom database and configuration filesfor easy maintenance and expansion.

ArchitectureWe approached the problem of identifying failed components using aspatial rather than a deductive method. In our spatial method, wedivided the card geographically into functional areas and theircomponents. The signals entering and leaving each functional areadefined a boundary. By testing the boundary signals, we narroweddown the number of possible faulty components to those within thearea that had an invalid boundary signal. We subdivided the areas intosmaller regions for testing in a similar way until we identified themalfunctioning component.

We were able to architect, design, develop, integrate, test/debug,implement, and deploy the custom test system from concept todelivery and training. We worked seamlessly with NI GPIB and VXIcontrollers and LabVIEW software to create an effective solution forthe client that will remain useful for years. By applying state-of-the-arttest techniques with productivity-enhancing LabVIEW features, wequickly generated a robust architecture.

For more information, contact:Crescent Luhman, Aegis GroupTel: (206) 447-4175E-mail: [email protected]

Crescent Luhman – Aegis Group

THE CHALLENGEDeveloping an easy-to-use, comprehensive testing system for VME-based satellite communication boards.

THE SOLUTIONCreating a scalable hardware, software, and firmware package that includes an intuitive, semiautomated interface and an easily configurable hardware fixture for each card.

ni.com/aerospace 41Aegis Group

Using National Instruments Software and Hardwareto Develop an Automated Test System for SatelliteCommunication Equipment

The AegisCustom Test SetUsing LabVIEW


Lawrence M. David Jr. and Terry Stratoudakis, P.E. –

ALE System Integration

THE CHALLENGEDeveloping a small, versatile test system that mimics the onboard communications of a military aircraft and analyses the communications for accuracy and completeness.

THE SOLUTIONUsing the NI LabVIEW graphical programming environment, NI Digital Waveform Editor software, and PXI hardware to designand develop a flexible and comprehensive test system.


Developing Digital Test Equipment for Navy AircraftCommunications Using NI LabVIEW and PXI

When a local high-tech electronics firm was awarded the contract tosupply a communications interface hub for a Navy surveillance aircraft,it was also tasked with designing digital test equipment (DTE) to verifythe initial functionality of the interface and provide ongoing verificationfor 20 years of field maintenance. Using the National Instruments PXIplatform, ALE System Integration provided expertise in hardwareintegration and software development for the system.

System RequirementsThe interface unit (the end product being tested) was designed to coordinate all the aircraft’s digital and analog signal routing,including the internal intercom, external radio, radar, and all digitalinstrumentation. The interface needs to correctly process allappropriate signals while ignoring corrupted signals and noise. To verify this functionality, the DTE needed to inject all valid andinvalid signals and interpret the interface’s responses.

In addition to verifying the aircraft’s functionality, the DTE neededthe capability to perform a self-test operation and the flexibility to

perform a one-time design verification including all flight-worthinesstests; additional electromagnetic interference tests; and a series ofphysical tests such as the highly accelerated life test (HALT), explosiveatmosphere, salt atmosphere, and thermal cycling. The DTE also hadto be able to inject and interpret the wide range of signals onboard theaircraft including analog audio, serial (9600 baud), high-speed digital (5 MHz), and MIL-STD-1553, a military standard serial data bus thatfeatures a dual redundant balanced line physical layer, time divisionmultiplexing, and a half-duplex command/response protocol.

Designing the DTE with PXI Hardwarefrom National InstrumentsThe DTE was implemented using an NI PXI-8196 controller containingthe following modules: NI PXI-6513, NI PXI-6542, NI PXI-2569, NI PXI-6511, and NI PXI-4060.

The PXI-6542 module was used at a clock speed of 20 MHzallocating four bits per tick of the 5 MHz device-under-test (DUT) clock, thus improving test accuracy. The NI-HSDIO software greatlyreduced development time. The system also included a Condor QPC-1553 from GE Fanuc Embedded Systems that included LabVIEW drivers to further simplify software development.

We also used two programmable power supplies, a three-phaseAC supply (GPIB) at 400 Hz to mimic the aircraft’s power, and a DCsupply (USB) to mimic internal supply circuitry. Both programmablepower supplies were interfaced to the system via the USB and GPIBports of the PXI-8196 controller.

Analysing Digital Test Data with LabVIEWWith a graphical user interface (GUI) developed using LabVIEWsoftware, the technician experiences improved flexibility in configuringtest runs of any of the 10 categories of tests in addition to a DTE self-test. The analysis capabilities of LabVIEW were instrumental infiltering and cross-referencing results from multiple categories of tests to pinpoint circuitry defects.

One constraint of this project was the simultaneous developmentof the test system and the interface unit. However, two majoradvantages of using LabVIEW to develop this system were theprototyping and debugging capabilities including custom probes and

highlighted execution. The code developed for the test system was reused to carry on the ongoing tests for the system.

We were able to develop the test systemwith ongoing changes to the specification and give invaluable support to our client intheir own development process. The key to

this success was the Digital Waveform Editor. With this tool, ourclient created digital waveform files using the editor, which we then fed into the test system. The resulting digital data file was easy for our client to review.

Overall, this was a great experience for our client. Using theLabVIEW and PXI platform, we delivered software faster than ourclient expected, and we were able to integrate seamlessly with their team.

For more information, contact:Terry Stratoudakis, P.E.ALE System IntegrationTel: +1 (631) 421-1198E-mail: [email protected]

“Overall, this was a great experience for our client. Using theLabVIEW and PXI platform, we delivered software faster than ourclient expected, and we were able to integrate seamlessly with their team.”

Products:NI Data AcquisitionLabVIEWPXI/CompactPCI

High-Speed Digital I/OMIL-STD-1553Digital Waveform Editor

ALE System Integration


ni.com/aerospace 43

PXI-Based RF Antenna Testing SystemLance Butler – B & B Technologies, an NTS Division

THE CHALLENGEDeveloping a cost-effective, portable system to generate modulatedRF transmissions at specific times over a variety of frequencies,power levels, and modulation types.

THE SOLUTIONProviding the ability to generate RF signals with a variety of parametersand transmit them through various signal paths at very precise timesusing LabVIEW and the NI PXI-5671 for flexible signal generation; andthe NI PXI-5660 for signal analysis and verification.

Products:RFPXI/CompactPCINI LabVIEW

Our customer needed a system capable of transmitting a variety of RF signals in a very controlled and flexible environment. We decidedto build the solution on the National Instruments PXI platform tominimise cost and size while maximising performance and flexibility.The solution called for three systems – one portable system for fieldwork, one static system for main testing, and one backup system tofill in for the static system in the case of a malfunction.

The payload waveform, which was designed using a separatecustom application, can be modulated using AM, FM, PM, PSK, FSK,MSK, or QAM. We set up scripts to send these waveforms at specifictimes for specific durations. The script utility lets the user definevirtually any form of looping, including iteration or time-based loops,frequency stepping, and power stepping; it also supports multiplepayload waveforms. In addition to the payload waveform, a headerwaveform is transmitted during each step of the script that provides a GPS timestamp and other parameters.

TestingTo begin a test, the user runs a waveform creator based on NationalInstruments LabVIEW to modulate a given signal using AM, FM, PM,PSK, FSK, MSK, or QAM. This software can run on any PC, and theresulting files are transferred to the system.

The system then designs a script in the main application todetermine which waveforms will be played, the frequencies to playthem at, the power levels to use, and the timing between eachstep. As an example, a typical script might call for waveform A(modulated using FSK) to be played at frequencies from 10 to 70 MHz in increments of 10 MHz, with a 30 millisecond delaybetween transmissions. Each of these cycles might be transmittedat powers from 100 to 500 W in 100-watt steps. The entire scriptmight then be repeated for waveform B (modulated as PSK).

The user then runs the script through a LabVIEW queue by loadingthe waveform into the NI PXI-5671 and setting it to trigger from the GPS card. The GPS card is loaded with the appropriate times for eachtransmission to begin. Using GPS for the timing allows extremeaccuracy in transmission start times.

Diagnostics and Other FeaturesSignal diagnostics are fully integrated into the system, which uses theNI PXI-5660 to provide a pseudo-real-time FFT of the transmittedsignal, and two ZTEC ZT002 cards to provide forward and reflectedpower measurements. Diagnostic scripts define a system baselinethat measures power and voltage standing wave ratio (VSWR) atvarious frequencies. A periodic system check is performed andcompared to the baseline to ensure that all system components are

functioning correctly.Power output iscorrected over theentire frequencyrange via a powercalibration mode.For any giventransmission, thesoftware choosesone of 12 antennasbased on frequency.RF relays accomplishantenna switching,which is controlled

by an NI PXI-6527 digital I/O module. The NI PXI-2565 switches thesignal path into a dummy load for baseline and calibration modes.

Using a manual mode screen, the user operates each of theinstruments independently to test various aspects of the system in anR&D mode. This feature combines with the signal diagnostics andremote access provide by Windows XP Remote Desktop so the usercan operate the system with confidence from hundreds of milesaway. With a scheduling utility, the user can schedule given scripts atany time in the future so the system can run unattended. In this way,users can remote in and apply all of the settings necessary for monthsof unattended testing.

System security and user monitoring are provided in two layers.Standard security measures such as a firewall to the Internet andWindows XP accounts provide the first layer. An access system inLabVIEW that requires users to log into the LabVIEW systemseparately provides the second layer. Three levels of user securityprovide differing functionality for different users. The system logs outa user after a given period of inactivity, but lets the system continuerunning scripts.

Because the system is considered mission-critical, backup powerand a backup system are included. The system automatically switchesbetween backup power sources, including solar, battery, andgenerator, with no power interruption. The backup system is anidentical PXI system that a user can switch to by simply moving theantenna cables from one rack to the other in case of a problem withthe primary system.

The PXI RF PlatformThe initial design of this system used Agilent rack-and-stackequipment rather the NI PXI platform. The switch to PXI moved theportable version from a trailer into a box that can be checked as airlinebaggage. The cost savings (after selling the Agilent equipment) wasenough to pay for a third system in entirety with money left over.Furthermore, with PXI, we could add much more advanced scriptingby driving the signal generator from the GPS card – a significantperformance benefit.

The PXI Chassis Packaged with Other RFComponents in a Shippable Container

B & B Technologies, an NTS Division


Military/Aerospace Case Studies44 B & B Technologies, an NTS Division

With the PXI platform and RF instruments available from NationalInstruments, we were able to design and implement a system thatwas not feasible only a few years ago. With the open-standard natureof the PXI bus, we could make additions from multiple vendors tomeet needs for features such as GPS time synchronisation and simpleRF power measurement.

LabVIEW Flexibility and Power Combined with PXIA great example of the benefits of LabVIEW and PXI came duringsystem development, when we needed to verify the signals we weresending. There was no hardware set aside for demodulating andanalysing our signal. Our customer thought that RFSA stood for an RF spectrum analyser that we had used to replace an old Agilent rack-and-stack spectrum analyser. We pointed out that RFSA actuallyreferred to a National Instruments RF signal analyser, which hascapabilities far beyond a spectrum analyser.

When we used the NI PXI RFSA to demodulate and decode asignal by writing a simple LabVIEW program using the NI ModulationToolkit, our customer was pleasantly surprised – not only was the PXI RFSA much smaller and cheaper than the old Agilent unit itreplaced, but it was also a much more flexible instrument. Bycombining the RFSA with LabVIEW and the Modulation Toolkit, we far exceeded our customer’s expectations in the analysis department.

For more information, contact:Lance ButlerB & B Technologies, an NTS Division6610 Gulton Ct. NEAlbuquerque, NM 87109Tel: (505) 345-9499E-mail: [email protected]

“With the open-standard nature of the PXI bus, we could makeadditions from multiple vendors to meet needs for features such as GPS time synchronisation and simple RF power measurement.”


ni.com/aerospace 45B & B Technologies, an NTS Division

Chris Cahoon – B & B Technologies, an NTS Division

THE CHALLENGETesting custom electronic equipment across a large geographicalarea (more than 25 square miles) and wirelessly sending the data to a centralised database for analysis and future storage, while thesystem employs up to 40 data collection units that simultaneouslyacquire data.

THE SOLUTIONAcquiring data with USB DAQPad devices and custom NationalInstruments LabVIEW software, relaying data to high-speed wirelessaccess points via 802.11g wireless communication, and transferringthe data to a centralised SQL database, while a PXI chassis with NIhardware monitors the health of each of the wireless access points.

Our customer needed to perform outdoor tests of militaryequipment in a rugged environment across a large geographicalarea. The data needed to be simultaneously sent to a centraldatabase for storage and subsequent viewing. To achieve this, webuilt portable wireless access points (APs) that can communicatewith a network and database at the central data processing centerusing high-speed wireless LOEA radios communicating at 1 Gb/s.Each AP also has its own local 802.11g wireless network tocommunicate with the numerous data collection units (DCUs).

TestingThe DCUs consist of either a durable laptop or tablet PC connectedto a USB NI DAQPad-6015 and a wireless 802.11g antenna. TheDAQPad works well because of its combination of portability,variety of relatively high-speed signals, and low cost. UsingLabVIEW, we created flexible modular software in a small amount of time. The software can measure up to eight analog voltages,read or output to eight digital lines, implement two counter/timerchannels for either event counting, frequency measurements, orpulse train output, and can read from RS232 serial ports. Using the LabVIEW Database Connectivity Toolkit working with MicrosoftSQL Server, we saved data directly to the database without makingcomplex network connections.

Each AP consists of a LOEA high-speed wireless radio, an802.11g local network, power provided by large solar panels and a propane generator, and a health monitoring system to ensure that the AP is working properly. The best choice for this healthmonitoring system was a combination PXI/SCXI chassis due to its compactness and high density of instrumentation. Each SCXI chassis contains an 1162HV module for reading high voltage digital signals and an 1102 thermocouple module connected to an NI PXI-6251 M Series MIO DAQ module to read up to 32 thermocouples.

A pan-tilt-zoom camera connected to each AP allows users in the central data processing center to view each AP and itssurroundings in real time. To implement this, we used an NI PXI-1411 IMAQ module to capture video from the camera, and a PXI 8421/4 RS485 card to control the camera’s pan-tilt-zoom functions.

Using the built-in TCP connectivity functions in LabVIEW, weestablished two-way communication between the central datacenter and each AP to send compressed live video data from theAP to the data center, as well as send camera control commandsfrom the data center to each camera.

Data Storage and ViewingAn LOEA radio in the central data processing center connects the SQL database to the high-speed wireless network. The databaseconsists of two terabyte servers connected to a domain controllerrunning Microsoft SQL Server. The overall storage of the system is approximately 6 terabytes of data. We used LabVIEW and theDatabase Connectivity Toolkit to create an application to allow the user to read, reassemble, and view the data from the database.With the power of SQL queries, we can store large amounts of data and find the data the user needs quickly.

Additional UtilitiesThe application also includes several additional utilities includingthe camera controller utility, a network pinging utility, and the APhealth monitoring utility. With the camera controller, the user canview live camera data from any of the connected APs and remotelycontrol the camera’s pan, tilt, and zoom functions. The networkpinging utility allows the user to send a network “ping” to deviceson the network, verifying that devices are connected to the

network. This utility is useful when trying to diagnosepotential problems with network connectivity. With theAP health-monitoring utility, the user can view live datatransmitted from the APs to the central database. Fromhere, the user can monitor AP input and output voltages,power consumption, and temperatures.

Wireless Data Collection System Across a Large Area

This Diagram of the High-Speed Wireless Network Was Created in a Short Amount of Time Through the Ease of Use of LabVIEW

“The fact that National Instruments hardware integrates so well with LabVIEW was a huge advantage while integrating the hardware with the software.”

Products:VisionPXI/CompactPCI

LabVIEWNI-DAQ


Software ConfigurabilityThe power of the database helps the user to independentlyconfigure settings for each DCU and store them in the centraldatabase. These settings include the types of measurements totake, the settings of each data acquisition channel, and the speed of data acquisition. Because the DCU retrieves its settings from the database each time it is powered on, users in the central datacenter can change settings locally so that users in the field indifficult environments do not need to make any adjustments while testing.

Advantages of LabVIEW and NI hardwareThe fact that National Instruments hardware integrates so well with LabVIEW was a huge advantage while integrating thehardware with the software. Using NI-DAQ instrument driversmade it quick and easy to configure and use the hardware. Themodularity of NI-DAQ also made it possible to use the samesoftware in my DCUs and APs despite the fact that the DCUs use USB based DAQPads while the APs use PXI-based hardware.The only instrument driver that needed to be written was for thecamera, which is really impressive, considering the variety ofhardware the system used.

For more information, contact:Chris CahoonB & B Technologies, an NTS Division6610 Gulton Court NEAlbuquerque, NM 87109Tel: (505) 345-9449E-mail: [email protected]

Military/Aerospace Case Studies46 B & B Technologies, an NTS Division


John Duncalf – BAE Systems;

Alastair Kane – TBG Solutions

THE CHALLENGECreating a new test suite for BAE Systems to efficientlycharacterise RF cables within major units of the Eurofighter aircraft.

THE SOLUTIONUsing the PXI/CompactPCI platform and National InstrumentsLabVIEW software to design a simplified test system that increases productivity by facilitating more flexible testing.

ni.com/aerospace 47BAE Systems /TBG Solutions

BAE Systems Uses PXI and NI LabVIEW to Develop an Efficient RF Cable Test Suite for the Eurofighter Aircraft

Products:LabVIEWPXI/CompactPCI

The Eurofighter Typhoon is a state-of-the-art combat aircraft devel-oped in cooperation with Germany, Italy, Spain, and the UK. This sophisticated, next-generation fighter has been engineered to meet military needs for generations to come. BAE Systems, aleader in these types of joint programs, has been working with otherleading aerospace companies to make sure the Eurofighter Typhoonis unparalleled in design and performance.

Developing an Effective Test Suite for RF Cables The company needed a new test suite for more efficient RF cablecharacterisation within major units of the aircraft. These units,produced at BAE Systems Samlesbury, have high-performancecoaxial cables that require testing prior to delivery to ensure that nodamage has occurred during installation. Every cable has a differentoperating frequency, cable length, and routing characteristics, andeach of these characteristics impacts performance.

The original method required specialist engineers to conducttesting, but this was expensive and it limited testing to a smallwindow of time. However, a system in which shop operatorsconducted the tests would mean more flexibility for production and the ability to conduct testing 24/7.

BAE Systems consulted with us at TBG Solutions to define theparameters needed for a more effective test system. The operators,who may have little RF engineering knowledge, would need toconduct all testing requirements for the three product areas. Thesystem would have to automate the test equipment setup routinesand test each product fully, including individually testing each cable as required.

We needed to develop a system that also would implement phasematching and one that BAE Systems could easily update for growth.Finally, we wanted the system to use the existing Anritsu scalaranalyser, and we needed the equipment to meet strict securityrequirements for use with potentially sensitive information.

System Design and Configuration The test system we constructed has four major components – the PXI controller, a vector measurement system, the existing Anritsunetwork analyser, and the software. The controller communicates withthe Anritsu network analyser through its GPIB interface. This helps theoperator measure scalar quantities, such as standing wave ratio and

transmission loss, in addition to vector quantities, such as phasedifference. We used NI LabVIEW, along with several NI toolkits, todevelop the application.

With NI tools, we developed the new phase-matching and data-capture software. We then customised this software for this particularapplication. Additionally, we created advanced custom analysisfunctions to manipulate the incoming data set for comparison againsttest procedure requirements. We then used the data to produce thetest report.

The system consists of two main sections – the PXI chassis,which contains the vector analyser, and the GPIB interface to thescalar system.

We assembled the PXI technologies in the NI PXI-1045 chassis tocreate a vector analyser, which helps operators accurately measurethe phase difference between two RF cables in the gigahertz range.The operators connect the cables under test across the two switchcards to minimise any difference in switching path lengths betweenthe two units. The test frequencies are in the gigahertz range, and anydelay introduced by either of the switch cards can result in inaccuratemeasurements.

All of the system hardware is stored in an existing 3U rack-mountable, rugged container for increased protection.

Overcoming Design Challenges During the design of the control software, we had to overcomeseveral challenges. Because the system is for operators with limitedknowledge of RF engineering, it was essential that the system displaythe right information for the operator to make the correct cableconnections without displaying redundant details. We achieved this by using picture rings to illustrate the setup, calibration, and testingsteps. These pictures show operators exactly what to connect and where.

BAE Systems Can View Test Results in a Graphical Format Using ThisSystem Based on PXI and LabVIEW

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We needed to tailor the system to BAE Systems-specific layoutdesign requirements and build it under tight security. Sections of the test procedure are considered sensitive, so we designed andimplemented the software without knowing the full test criteria. Forsensitive parts of the test, the operator must enter those parametersbefore beginning each test. This means all information is kept involatile memory and is lost if the system is shut down, thus meetingBAE Systems’ security requirements.

The test system also must determine when a system calibration isrequired. We attempted several test-sequence iterations to ensure wekept calibrations to a minimum because they have an adverse effecton test duration. With the resulting sequence, operators can batchtest cables at the same frequencies, as long as there are no physicalrestrictions due to the design of the aircraft.

We controlled the vector analyser through the GPIB interface toconduct all calibration and test routines without operator interference.This was particularly difficult because the analyser was in constant useand could not be released for off-site work. We developed the controlVIs off site and commissioned them on site when production programtime allowed.

Producing Easy-to-Use Results The combined system produces results for all tests conducted oneach product, and the operator can produce a printout anytime.

The system displays the results in graphical and tabular formats and produces a detailed cover sheet that shows the time, date,operator, and product identifier for the test subject. The graphicalformat illustrates all values for the required 401 test points, with limitlines to show the pass/fail criteria. The tabular format shows themaximum values achieved and includes a pass/fail box for clarity.

Using the LabVIEW Report Generation Toolkit for Microsoft Office,operators can record the results in Excel documents. With theseresults, aircraft inspectors can see quickly and easily the overall resultand keep the graphical detail sheets for future reference.

Simplifying the Test System BAE Systems laid out the system specification in the early stages of this project; however, we understood that this would be adevelopment project. The system has met or exceeded the originalspecifications and demonstrates that it is possible to automate RF testing without the operators having RF theory knowledge.

We saved more time than originally anticipated, and the operationof the final product is so simple that operators need only minimaltraining. In fact, this method of testing has proven to be so successfulthat other BAE Systems departments are considering using thissolution to meet RF testing requirements for high-performance coaxial cables.

For more information, contact: Alastair Kane, Systems Engineer TBG Solutions, Inc. Unit 9, Century Street Industrial EstateDon Valley, Sheffield 59 5DX Tel: 0114 261 8111Fax: 0114 256 2456E-mail: [email protected]

Military/Aerospace Case Studies48 BAE Systems /TBG Solutions


ni.com/aerospace 49

Automatic Test Equipment for RadarTesting and Qualification

Fiar S.p.A.

R. Lauricella and A. Pozzi – Fiar S.p.A.

THE CHALLENGETesting the radar functionality and performance automatically, withoutthe presence of the operator, and in different environmental conditions(commanding a burn-in chamber); and producing a detailed, automaticreport in order to certify equipment. The bench is also able todownload the radar software of all the processors inside the radar.

THE SOLUTIONProducing software inside LabWindows™/CVI using the existinglibraries for commanding GPIB and VXI buses and using DIO boardsto command and capture signals, which are run-time processed andanalysed. Active-X is used for generating automatic reports in Excelformat describing the test session results.

Starting from undownloaded radar, the bench is able to download it,and using the serviceability test, it is possible to have the feeling of theradar behaviour. The following step is to test the radar deeper by usingthe acceptance test procedures and to verify the performance by thequalification procedure. If any failures are detected, the operator isable to detect the board(s) where the failure is located by following thetroubleshooting procedure. All the subsystems that are automaticallycontrolled are also reproduced on the bench display, to allow theoperator to command them individually and remotely.

Introduction The project target is to verify radar functionality and performance.The bench has been designed using some auxiliary commercialequipment connected on different buses under the bench PCcontroller. The hardware architecture is presented on the bench displayat the program start-up during the initialisation phase that automaticallychecks the equipment presence on the relevant bus (see Figure 1).

Moreover, the bench is connected to the radar test accessconnector using DIO boards NI PCI-6533 (DIO-32HS) and PC-DIO-24Plug-and-Play, in order to stimulate radar performance and monitor the radar behaviour.

The software is developed using LabWindows/CVI multithreading to carry out different tasks, obtaining a more efficient response andbetter performance.

The multithread facility permits us to carry out parallel procedureson each bench bus without any sort of conflict. It is possible to capturedata from each bus for analysis and data logging.

Automatic test sequences represent the bench software core, but the bench is also used for commanding the radar main bus directlyin order to simulate the aircraft movement and analyse the radarresponse. A GPIB-commanded target generator is put in front of thebench like a scenario simulator.

Hardware System The hardware system is composed of the following subsystems:

n Power supplies (3 phases, AC and DC) on the GPIB bus, enablethe radar equipment to switch on and off, and to monitor the current. GPIB-specific commands can simulate transient and voltage drop for electrical tests.

n The dynamic motion table, on the GPIB bus, simulates the aircraftmotion, and by using GPIB-specific commands, it is possible toproduce particular aircraft trajectories and maneuvering.

n The optical bench table, on the GPIB bus, simulates the target presence. Using GPIB-specific commands, it is possible to change the target type, shape, and number.

n Using an oscilloscope, multimeter, and video sync generator onthe GPIB bus, the operator can detect failure by analysing signalsand data. These instruments can be individually and remotely controlled by the operator using the man machine interface.

n The liquid cooling unit, on the GPIB bus, cools the radar andchecks the liquid’s temperature, pressure and flow rate. Thesedata are run-time monitored by specific GPIB commands.

n The radar test access connector box is connected to two NI PCI-6533 (DIO-32HS) boards for time-critical signals, and PC-DIO-24 Plug-and-Play for I/O data-capturing operation.

n A switch matrix and HF multiplexer, on the VXI bus, are used to multiplex different test access connector signals and different video outputs.

n The 3838/3910 interface, on the GPIB and VXI buses, simulates all the commands that can run to the radar bus. The GPIB bus is used for setting the equipment, and the VXI bus is used fortime-critical operation and data changes.

n The burn-in chamber, connected to the bench using RS485 and two PCI boards, can set different temperature cycles and monitor the environmental parameters.

Figure 1. Bench Startup Panel, Showing a Synthetic Display of the Bus Architecture)


Products:Serial 485/2 PCI PCI-6533 (DIO-32HS)GPIB PCIGPIB PC II/IIA

PC-DIO-24 Plug-and-PlayData Acquisition

PC-AT MXI-2010 Controller LabWindows/CVI


Software System The project has been developed in LabWindows/CVI using its powerful,relevant multithreading, user-friendly interface, and the ability toproduce very complex software in a very short period of time (thelibraries are very helpful). The software has been designed to executefully automatic test procedures such as:

n Bench Selftest – Allows checking the presence of the bench component and initiates each subsystem self-test. The test result isthen presented to the operator and the type of failure is displayed.

n Radar Software Download – Updates the radar software thatdownloads all the radar processors. A typical protocol (reserved) mustbe respected on the 3838/3910 bus after downloading, verifying theprocedure’s start, and checking the memory contents. Automaticrecovery conditions are managed in order to proceed if no critical errors are detected – message retry, block retry, and program reload –otherwise the download procedure stops, advising the user on theproblem detected (see Figure 2).

n Radar Serviceability Test – A fast, but not exhaustive, test to verify main radar functionality, and to point out trivial problems.

n Radar Purchaser/Product Acceptance Test Procedures (ATPs) –These represent the client’s benchmark in order to verify the radar functionality. All the test steps have a pass/fail report and adetailed report is produced using Active-X libraries. The purchasersaccept the radar after the product ATP executes without fail, then the ATP certifies/demonstrates the radar functionality.

The Purchaser ATP is carried out by the purchaser inside hiscompany – he receives the radar before installing it on the aircraft.

n Radar Software Acceptance Test Procedure – Tests all the software requirements specified inside the SoftwareRequirements Specification document, produced and accepted by the Purchaser.

n Radar Qualification Procedure – Represents the most powerfulautomatic test because it is able to demonstrate the radar electrical and environmental performance. Moreover, it is able to detect and isolate critical areas.

All the bench subsystems are stimulated automatically usingGPIB and VXI interfaces, and high-speed acquisition is used forhigh-speed data capturing. During these procedures, the trajectoriesof the aircraft and the targets are simulated. (See Figure 3).

n Radar Troubleshooting Procedure – Used in the event thePurchaser/Product ATP has detected failure(s). With this feature, it is possible to command particular test sequences in order toautomatically establish in the board(s) where the failure(s) is (are) located.

The failures insulating regarding boards are as follows:n 100 percent on three boardsn 95 percent on two boardsn 90 percent on one board

Figure 3. Trajectory Simulation Panel

Military/Aerospace Case Studies50 Fiar S.p.A.

Figure 2. Download Procedure Panel (data reserved / not shown)

Figure 4. Burn-In Procedure Panel with Temperature Profile Set and Report Display


ni.com/aerospace 51Fiar S.p.A.

Each radar board can be addressed in order to send and receivecommands, to detect if it is working properly, or if the failure can be located. The failure detection is 100 percent of the failuresdeclared inside the Failure Catalogue.

n Radar Burn-In Procedure – Allows checking the radar behaviourby simulating the critical environmental operating conditions duringthe mission. Using RS485 and 2 PCI boards the bench is able tocommand the thermal chamber, which simulates the following:temperature profile; vibration profile in terms of frequency, amplitude, and timing; and blower profile to stimulate a particularradar area (for example the increasing of temperature).

During the environmental cycle, which runs for 72 hours, automatic electrical tests are carried out and the data results arelogged throughout the test duration. The user can extract the test log file in order to determine the radar quality (see Figure 4).The LabWindows/CVI interface is user-friendly, and has reducedthe software architecture (events management).

n Radar Characterisation/Calibration Algorithm – Permits download of typical (reserved) radar parameters to adjust the radar image and functionality quality.

Conclusion During the development of the bench implementation, we appreciatedLabWindows/CVI, because it is very powerful and user-friendly. Thedesign has been very interesting for the variety of the problems thathave been presented and solved. The bench is actually being used inour company by the radar integration team, and has been delivered tothe Purchasers and to other members of the consortium.

“The project has been developed in LabWindows/CVI using its powerful, relevant multithreading, user-friendly interface, andthe ability to produce very complex software in a very shortperiod of time (the libraries are very helpful).”


Military/Aerospace Case Studies52 Harris RF Communications Division

Using R Series Intelligent Data Acquisitionfor Bit-Error-Rate TestSteve Kulakowski – Harris RF Communications Division

THE CHALLENGEReplacing traditional box instrumentation to support the testing of new and current product offerings.

THE SOLUTIONUsing National Instruments LabVIEW FPGA and R Series intelligentdata acquisition to develop a more flexible system to test real-life file transfers while reducing cost per unit by 4X.

At Harris, an international communications and informationtechnology company, we needed to replace our traditional boxinstrumentation in order to support testing of new and currentproduct offerings. The main RF products we test are a datatransmitter and a data receiver, with three different serialinterfaces that must be validated. The older system supported alimited number of communication types, so we needed to find an off-the-shelf solution that was both flexible and scalable.

Bit-Error-Rate (BER) Test SystemUsing a National Instruments PXI-7833R FPGA module and an external wide area network (WAN) transceiver integrated circuit (IC)on a custom-printed circuit board, we implemented a complete serialbit-error-rate (BER) test system. The physical interfaces that needed to be validated were RS232, RS422, and RS485, the latter two beingbalanced interfaces for high-speed applications to 1.6 Mb/s. Theoriginal system only supported 8-bit synchronous and asynchronouscommunication interface types, and at a much higher cost.

The interface to the R Series PXI-7833R module is a customisedprinted circuit board that utilises a Sipex SP514 WAN interface IC forthe different physical layer serial interfaces. The board also contains atemperature compensated crystal oscillator (TCXO) and a direct digitalsynthesis (DDS) circuit to generate the higher-speed clocks that thePXI-7833R uses to synchronise data. The 1 ppm TCXO is available tothe user as a high-stability clock source for the UUT, and is available for future use for jitter testing and analysis. The data port interface isbased on the EIA- 530 communication standard on a DB-25 connector.For added signal integrity at higher speeds, we ran coaxial lines for allthe clock and data lines.

The target NI LabVIEW FPGA VI contains all the functionality of atypical BER test system. The VI accepts all user inputs to configuretiming, physical interface, block size, handshaking signals, andpreamble block size. We also had the option to insert one bit error fora system test. The bit error function randomly inverts a transmittedpattern bit and effectively modifies the transmitted data. Thesefunctions are also directly available from the host VI, which providesreal pattern data and performs post-test analysis on the received data bytes to report BER, bit errors, lost bits, and sync.

System Synchronisation To repeatedly achieve synchronisation within the system, the BER tester serially transmits preamble data of a user-specified size,generally less than 255 bytes. The FPGA code checks against and

compares preamble bytes and stop bits to indicate to the user or test that synchronisation has been validated. (This is also done at each specific byte compare within the pattern transmission.) If a failure occurs and there are significant bit errors, a file isgenerated for the user to compare sent and received data as seen by the BER tester. If no sync is detected and preamble bits are still available, the target code employs a clock-shifting methodto try to align received input data with preamble data values. If no synchronisation occurs within the small preamble data block, the test system will report “no sync” on transmission and start a retest.

Essentially, the test usually involves two Harris products, one asa data transmitter and one as a data receiver, with an appropriatephysical interface to the BER tester. The systems are usuallyconnected through several feet of 50 Ω cable through an RFattenuator to assure good sensitivity and a high signal-to-noise ratio between the communication products.

A pre-specified random or pseudorandom data pattern is transferredto the transmitter system under test at a specified baud rate; the new BER tester can test at rates up to 1.6 Mb/s. The information ismodulated by the transmitter system and transmitted via RF at aspecified carrier frequency. The receiver system receives the RF,demodulates it, and retransmits it back to the BER test system.

At that point, the BER test system algorithm compares receiveddata with transmitted data deterministically and reports the number of byte errors. The transmitted and received data is stored in target memory and later retrieved by the host VI application toreport pattern bit errors and compute pattern BER. The BER testapplication algorithm also reports lost bits and synchronisation time.

Products:NI Data AcquisitionDigital I/OLabVIEW

LabVIEW FPGA ModulePXI/CompactPCINI TestStand

Harris RF Communications Division Developed the Control Panel Aboveas Part of a Bit-Error-Rate Test System That Is Reducing Cost by 4X


ni.com/aerospace 53Harris RF Communications Division

High-Speed Serial Data ProcessingTo achieve high-speed serial data processing to 1.6 Mb/s, theapplication needed to compile and run at an FPGA clock speed of 80 MHz. We needed the data to be processed within 20 nS dataresolution, and with the new system, we have now guaranteed targetprocess time of 12.5 nS/bit. This is critical for relatively slow internalmemory operations and real-time data comparison. We optimised thetarget VI to compile the application repeatedly at 80 MHz on multipletest systems.

We implemented deterministic data comparison using directpattern memory comparison with the LabVIEW FPGA customizablememory block. The memory block was necessary to increase thepayload data transfer and compare; otherwise, only very small datablocks would be transferable. Currently, up to a 30 Kb data pattern isavailable to the user in a drop-down menu.

Calling the target software from the host VI is a critical integrationstep to support full ATE product testing. Our current test softwarestructure uses LabVIEW and NI TestStand.

The test unit has the ability to execute a self-test using a loop-backcable that ties clock and data together, as well as using an SPDTswitch to emulate modem handshaking lines required to validate the

test setup. The test should always result in a zero loss result, meaningcomplete sync, 0 bits lost, and 0 bit errors.

One of the problems we encountered when trying to find an off-the-shelf solution that supports the PXI test platform was finding options that were customizable to work with our productcommunication interface and test. The first instrument option wefound did not meet the interface requirements of our product base.With the LabVIEW FPGA test option, we can test several serialcommunication physical layers without bulky interface cards. Thenew instrumentation also provides much added flexibility to testreal-life file transfers and possibly serialised images betweensystems. It is also a PXI-based solution.

ConclusionThe new system reduces cost per unit approximately 4X, and offers customisation capability to communication interfaces that have added test requirements.

We are currently investigating very high-speed systems (greaterthan 2 Mb/s) using two PXI-7833R reconfigurable FPGA modules.

For more information, contact:Steve Kulakowski,Test EngineerHarris RF Communications DivisionRochester, NY 14610

“Our new system reduces cost-per-unit approximately 4X, andoffers customisation capability to communication interfaces that have added test requirements.”



Advanced Topologies for System-LevelTesting and PCB ConfigurationJames Stanbridge – JTAG Technologies, UK

THE CHALLENGEDeveloping a system-level test of an advanced military airborne radarprocessor constrained to use a legacy test access connector (TAC)carried over from the previous design revision with only a few sparesignal lines available. This constraint has meant that only a single JTAG test access port (TAP) could be presented externally.

The JTAG topology also needed to account for the possibility that a part of the system may be powered down under faultconditions, or that some modules may not be fitted. Additional fail-safe features were required to prevent spurious JTAG accessescausing unexpected switch-on/switch-off of system modules.

THE SOLUTIONUsing start-of-the-art JTAG/boundary-scan software tools and commercial TAP topology devices such as National SemiconductorScanBridges, construct a system level test access network.Additional NI hardware and application executive software elevates the system from JTAG/boundary-scan only to a functional test system.

The SELEX airborne radar in question is a scalable design featuringa dynamically reconfigurable active backplane servicing a number of vector processing (VP) cards. In the event of board failure, thedesign allows for a graceful degradation of service by shuttingdown power to the suspect board via the intelligent back-plane. Amaster communications processor allows access to the VP boardsvia EFA bus standard, Radar Bus interface, receiver interface and video interfaces.

Within the test system, an NI PCI-6533 is used as an interface to our EMId (electronic module identification) devices on each SRI(shop-replaceable item). These hold part number and serial numberdata, and so on, along with a log of recent fault detections. The PCI-DIO-96 is translated into a 160-pin DIO using a bank of CPLDsthat multiplex outputs and inputs from the I/O card in the testcontroller PC. The system includes optional latching of input events(to catch transients) and full bi-directional operation. 16 I/O pins areused as control and status signal, while the other 80 aremultiplexed to give 160 outputs and 160 inputs to simulate and testthe digital interfaces.

JTAG/Boundary-scan testing and ISP (in-system programming)is a pivotal part of the system and is now considered now the oneof the principal methods used to check circuit boards (PCBs) andsystems for assembly faults during manufacture and prototypedebug) and field service failures in deployed equipment.

Relying as it does on test circuitry built-in to today’s highlyintegrated digital devices (compliant with IEEE Std 1149.1),boundary-scan testing requires only a minimal test interfacecomprising four or five digital connections. This can be contrastedby the vastness of traditional bed-of-nails test systems requiringmany hundreds or even thousands of test probe connections.Consequently, boundary-scan testers can be reduced to the size of a serial protocol interface unit, which may be supplied as a PCI,PXI or compact bench-top (USB/Ethernet) controlled unit. By simplyadding power supplies to the system, an autonomous PCB testercan be quickly brought into service. What’s more, with careful

product design utilising ScanBridge TAP multiplexors, a singlecontroller can also be used to access a series of PCBs within a system and a system/LRI (line replaceable item) tester is born.

This airborne radar makes extensive use of such ScanBridgedevices to subdivide the system into logical accessible modules. Adding further peripheral interface hardware such as analoguemeasuring instruments and test signal multipelxors, the system isupgraded the from a “structural” boundary-scan based tester to a full-fledged mixed-signal test system incorporating functional test capabilities.

Products:LabWindows™/CVIPCI-6533PCI-DIO-96PIP/LW

BSD, JT 3727/TSI (JTAG Technologies) LeCroy High-Speed DSOProgrammable PSU

JTAG Technologies, UK

Radar Processor Backplane JTAG Topology

The mark LabWindows is used under a license from Microsoft Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and other countries.


ni.com/aerospace 55

Northrop Grumman Uses NI LabVIEW andDIAdem for Rapid Telemetry Data ManagementOmar Mussa – Northrop Grumman Space Technology

THE CHALLENGECreating an inexpensive method for quickly locating, organising, and analysing binary telemetry data files.

THE SOLUTIONUsing National Instruments LabVIEW and DIAdem to generatea custom DataPlugin file and integrating that file with the NI DataMine application.

Products:LabVIEWDIAdem

Northrop Grumman is a leading global defense company and providerof a broad array of technologically advanced solutions in defense electronics, information technology, advanced aircraft, and space technology. We were recently selected by the U.S. Air Force to participate in the development of a revolutionary new ballistic missiledefense system, the Airborne Laser (ABL).

The ABL system consists of a laser mounted on a modified Boeing 747. During each second of operation, thousands of telemetrypoints monitoring the health and status of the system are stored intobinary data files. These files grow in both size and number over time.Managing the files so that engineers can efficiently diagnose andreport testing events is a difficult problem. We needed a tool that can quickly analyse these files while meeting several demandingspecifications. The parsing algorithm must be flexible so that if themessage format changes, the program can quickly be adapted to thenew system. Test data must be organised so that engineers can easilyfind test data for months, or even years, after the completion of aparticular test. The system must also be able to handle large files (>50 MB) without choking, and it must allow the end user to analysethe data in several ways, using Microsoft Excel, The MathWorks, Inc.MATLAB®, or other scripting programs. Finally, the system must be asmaintenance-free as possible.

Our schedule and resources did not warrant investing a lot of timedeveloping a suite of custom reporting tools from scratch, so wedecided to use the free NI DIAdem DataMine example application that was discussed in the application note Self-Configuring DataManagement System Based on LabVIEW and DIAdem.

The DataMine application consists of National InstrumentsLabVIEW executables that interface with a Microsoft Access databaseused to store and file metadata such as test time and file name, alongwith the file path to the raw data files. The DataMine application alsocomes with scripts and graphical user interfaces (GUIs) that can run inDIAdem to search and extract metadata and raw test data. Using theDataMine application, our development effort was limited to parsingthe file correctly in the DataPlugin. (DataPlugins are Visual Basicscripts that are registered with Uniform Storage Interface, or USI, andprovide data translation services, allowing access to customer-definedfile formats.) Using this system, we eliminated the need to buildcustom GUIs and reports altogether, saving hundreds of design, code,and test time man hours.

The flexibility of the DataPlugin architecture is a key component of our solution. As the format of the data we parse changes, we caneasily adapt our code to support these changes. Additionally, some ofthe telemetry fields we parse are actually status bytes that require

further parsing in order to isolate the useful information into a datachannel. Our test data files are also mixed between ASCII texttimestamps and raw binary data. All of these issues are very easy to accommodate within the DataPlugin architecture.

Data formatting is also important to us. We use the DataPlugin topopulate the channel properties, such as “units,” as the files areparsed, making it easier for the engineers to analyse the data. We alsoscale the values from within the parser so that other scripts or reportsthat read the data will not require further processing of the raw dataonce it has been parsed by the DataPlugin. This gives us a lot offlexibility and scalability for future applications.

After generating the DataPlugin, we were pleased with how easy it was to integrate with the DataMine application and DIAdem. Toregister our DataPlugin with DIAdem was a simple process, andDIAdem generated a registration (.uri) file that can be used to installthe DataPlugin on other machines. Additionally, the DataPlugin can be associated with a file extension and automatically used to importdata of a particular type. We use this feature to prevent bad data frombeing imported into the system, giving the engineers control overwhich files are managed via the file names.

Using DIAdem and the DataPlugin architecture, we achievedsignificant efficiency improvements in handling large datasets andmanaging our data. This application has become the focal point of our analysis effort, and we are pleased with both the results and the low cost of the project.

For more information, contact:Omar MussaNorthrop Grumman Space TechnologyOne Northrop Grumman AvenueEl Segundo, California 90245Tel: (310) 812 0203E-mail: [email protected]

Northrop Grumman Space Technology

MATLAB® is a registered trademark of The MathWorks, Inc.

Northrop Grumman Uses NI LabVIEW and DIAdem to Quickly Develop the Data Management SystemUsed for the Airborne Laser Project



Designing an Automated RF Test Systemfor Flexible Data Mining and Reportingwith NI LabVIEW and DIAdemJames West – Summitek Instruments

THE CHALLENGECreating an automated RF test solution for improved analysis and reporting of historical test data.

THE SOLUTIONAutomating S-parameter measurement and developing a Web interface for comprehensive testing and report generation usingNational Instruments LabVIEW and DIAdem.

S-parameters, which help characterise the performance of passive and active devices, can be viewed in a variety of formats to provideunique insight into the characteristics of a device under test.

Two different customers challenged Summitek Instruments tocreate an Automated RF test system that automates S-parametertesting and improves their ability to analyse and retrieve data. One customer needed a better way to find historical test data andreproduce results, while the other wanted a more effective method for finding and analysing test data for statistical process control (SPC).

Searching for a Better Method of Analysingand Retrieving Test DataEach customer already had a process for performing S-parametermeasurements but no way to effectively access the data. We knewdeveloping a proficient system would encompass:n Identifying a test data storage method that does not require

a customised file format for each customern Designing a test system that customers can adapt to fit

their test processesn Providing tools to easily mine and analyse test datan Producing high-quality reports that customers can distribute

as data sheets

Making the Test System Accessible toBasic and Advanced UsersThe first problem we solved was finding a generic test data storagemethodology. We needed a solution that could store S-parametertest data and custom user fields, as well as offer the tools necessaryto access the test data. For this, we used the data storage VIs inLabVIEW. The data storage VIs provided a way to store S-parametertest data as well as custom information related to each test and product.

The data storage VIs use XML-based technology to build aninformation hierarchy, which stores file, group, and channelinformation in .TDM files. We mapped the hierarchy so that filescorrespond to the products under test, groups correspond to each testrun of a product, and channels correspond to each measurement.We asked the customer to customise fields to associate with eachtest run (group). These customised fields are stored as properties ofthe test run. With the data storage VIs, we could store different datafor each test run and each product tested. We also could store customfields with the test data without a custom test data file format.

In addition, we wanted to provide a user interface that would befamiliar to customers and give them the ability to release ongoingimprovements to the product. We chose to use a server-basedproduct strategy, which presented some not-so-obvious advantagessuch as the ability for customers to install their products on onecomputer and obtain access from multiple client locations. Forexample, test engineers in the United States can configure testsequences and access test data from a server in China. Anotherbenefit to this approach is that customers can install improvements to the software on the server and make them immediately availableto multiple test stations.

Our Spartan product uses an NI LabVIEW remote panel-basedsolution, and the Web interface we developed helps our customersconfigure and run tests as well as generate reports from a Webbrowser. Customers define which custom fields to use along with the S-parameter test sequences for each test run. Additionally, theSpartan collects the custom fields from the production technician andstores them and the test data on the Spartan server in .TDM data files.Company employees are able to generate test reports from anylocation with access to the Spartan server.

A database on the server combined with the .TDM data filesprovides an integrated solution that fulfills all of our requirements.Customers can store test parameters and the test data index in theSpartan database and the test data in the .TDM data files. Customersare able to search for data using standard fields such as product modelnumber, serial number, or production technician name, and can datamine custom fields such as customer purchase order number or workorders. We created a simple query tool that constructs an SQL queryfor the test data index. The query results in a list of test data files thatfit the criteria. As a result, customers are able to retrieve lists ofproducts grouped by test station and perform SPC more efficiently.

We used NI DIAdem to load .TDM test data and report templates.Because DIAdem naturally incorporates the ability to access .TDMdata files, it facilitates quick development of report-generationcapabilities. With the rich features of DIAdem, customers canproduce professional reports, including PDF reports, withoutextensive custom software.

Summitek Instruments


ni.com/aerospace 57

A solution based on DIAdem offers other benefits. Advancedusers can access the .TDM data files and create custom reportsand custom analysis to fit their special needs. A complex data-mining tool in DIAdem offers additional capabilities beyond thescope of our test system. And, by using DIAdem in the Spartanproduct, we can accommodate basic and advanced users.

Savings Achieved with SpartanUsing data mining within Spartan, one customer was able to findand reproduce test data reports immediately, whereas thecustomer previously spent hours searching through boxes lookingfor printed test results. The customer was able to save on laborcosts and shift the technicians to production.

We cut development time for our report-generation capabilitysignificantly and realised a dramatic savings from concept to report as compared to prior projects with report-generation capability. Elimination of custom file format definitions for each customer saves development time, so we can concentrate on adding features to the product.

For more information, contact:James WestSenior Software Engineer,Summitek Instruments12503 E. Euclid Driver #10Englewood, CO 80111Tel: (303) 768-8080E-mail: [email protected]




Spectrum Monitoring and InterferenceAnalysis Using NI PXIJim West and Jim Pierson – Summitek Instruments

THE CHALLENGEIncreasing the functionality and expandability of a spectrumanalyser for improved RF environment monitoring andinterference management.

THE SOLUTIONPairing National Instruments PXI hardware with the OASIS spectrummonitoring package to deploy multiple spectrum analysers with highthroughput and improved service.

Products:LabVIEWRFPXI/CompactPCI

Interference is becoming more prevalent in the wireless communitywith the increasing number of transmitters coming on the air.Wireless service providers have traditionally used spectrum analysersto monitor their channels and frequencies and the adjacent spectrumand to locate sources of interference. Unfortunately, a spectrumanalyser can only show the interfering signal to the user, who mustthen determine the source of the interference. To solve interferenceproblems, the user must understand the RF environment, knowwhich transmitters are operating nearby, and identify any new or unlicensed emitters.

We identified the National Instruments PXI-5660 RF vector signalanalyser and the NI PXI-5690 RF preamplifier as the ideal hardwarecombination to pair with our OASIS spectrum-monitoring package. The PXI form factor allows us to deploy multiple spectrum analyserswithin the same compact space as a single benchtop spectrumanalyser. Plus, the NI PXI-5660 offers higher data throughput andcomparable specifications to traditional spectrum analysers.

OASIS requires no software development and extends thecapabilities of the PXI-5660 by letting the user view multiple frequency ranges simultaneously, or in the case of multiple vectorsignal analysers, remotely control the instruments with a single user interface.

The system has an extensive set of tools that automaticallycharacterise an RF environment and compare the actual environmentto a database of known emitters. It then constructs a database bymonitoring the local RF environment or by accessing a database ofFCC-licensed emitters in the United States. Users simply enter thefrequencies being affected by interference, and the system generatesa list of the suspect emitters in the area that could be causing theinterference. The PXI-5660 then tests the suspect emitters. Thissolution reduces the amount of time spent in the field and providesreports that can be used to prove interference.

The PXI-5660 and OASIS combination provides data to supportspectrum management processes through archival data storage,unattended and remote operation, and data post-processing. It alsohelps ensure compliance with spectrum regulations by quicklyidentifying licensed and unlicensed emitters, and by trackingnoncompliant transmitters with emission masks and limits. Thissolution provides an easy, economical way to identify sources ofinterference, find rogue emitters, and manage spectral usageefficiency from channel occupancy statistics, helping to ensure quality of service and network reliability.

The complete hardware and software solution is moreefficient and economical thanmost benchtop spectrumanalysers alone. The off-the-shelfsystem is highly functional, and requires no softwaredevelopment. Users can recordand view multiple frequencybands on a single NI PXI-5660 to quickly resolve interferenceissues. The system alsoperforms unattended datalogging for hours, days, or

even weeks for later analysis, further reducing time spent in the field. Users can also save time and money by remotely monitoring testlocations and changing test scenarios over an Ethernet connection,eliminating the need to travel to and from test locations.

With the logging capability, users can collect data and essentiallyperform unattended spectrum monitoring, capturing and storing the spectral data to perform other tasks instead of spending timewatching a display. By logging data, the operator can see not only the event of interest, but also the spectral data before and after the event.

Using OASIS with the NI PXI-5660 is an excellent off-the-shelfsolution for customers who need a spectrum monitoring solution but do not want to spend the time developing their own code.Users save time and development costs while maintaining flexibility for future development of custom applications usingNational Instruments LabVIEW.

The system also allows remote control and data collection. Userscan set up the NI PXI-5660 at essentially any remote location, and usean Ethernet TCP/IP connection to remotely control and collect datafrom the instrument, eliminating travel time and cost. With thissolution, users can control up to four NI PXI-5660 instrumentsremotely and display their data simultaneously. These instruments can be in the same PXI chassis or they can be distributed at differentlocations. With this flexibility, users can control multiple instrumentsremotely, and set up a network of monitoring locations if need be.

For more information, contact:Jim PiersonSummitek InstrumentsTel: (303) 768-8080Fax: (303) 768-8181E-mail: [email protected]


A Sample Report Generated by thePXI-5660 and OASIS Combination


ni.com/aerospace 59TELESPAZIO

M&CVIEW: Satellite Ground Station Monitoringand Control System Based on LabVIEWG. Rozera – TELESPAZIO

THE CHALLENGECreating an in-house monitoring and control application for a satellitetracking telemetry and command station, which is responsive tocustomer requirements, and not dependent on third-party configurablemonitoring and control systems.

THE SOLUTIONUsing the LabVIEW graphical programming environment to build the application, and adopting PXI-RT as equipment front-end, and LabVIEW Datalogging and Supervisory Control to handle the database.

Products:LabVIEWLabVIEW Datalogging and Supervisory Control ModulePXI Real-Time

M&CVIEW has been developed in Telespazio to respond to monitorand control requirements both for customers and Telespazio-ownedTacking Telemetry and Control (TT&C) stations.

In past years Telespazio was used to configure third-party softwaresystems to create a monitor and control system.

A third-party configurable system is acceptable when the job to do is similar for every system; but it may lead to problems whenadditional functionalities are needed to meet customer requirements;each added functionality results in more expense, tests and time.

Telespazio is not a software house, but knows how to managesatellite ground station systems; LabVIEW is not a traditionalprogramming language but has a great ease-of-use and lots of ready-to-deploy device-controlling tools: here are good joint venture bases!

M&CVIEW allows centralised management of complex satelliteground stations, and is able to control a great variety of equipment and its application is not limited to satellite ground stations. M&CVIEW software architecture splits into three main functions: n Front-End n Central Manager n HMI (human machine interface) These three functions can

be co-located or distributed on different hardware platforms

Front-End The Front-End facilitates command-sending and status informationretrieval to and from the equipment. It translates various equipmentcommunication protocols in a common data format adopted inM&CVIEW. It forwards monitoring data to Central Manager andcommand data to the equipment. The Front-End runs independentlyfrom the Central Manager. It dynamically opens all communicationlines to equipment and loads equipment drivers needed to do its job,while maintaining a real-time picture of monitored data performingcontinuous equipment polling.

During its work, the Front-End continuously checks equipmentconnection status and starts recovery actions in case of link failure.The Front-End allows connection of one or more Central Managers to get monitor data; only one Manager is allowed to send commandsto equipment. Front-End can operate with a wide choice of interfaces:digital I/O; serial lines (RS232, RS422, RS485 2/4 wires); and TCP/IP,UDP/IP, and SNMP, where Front-End operates as SNMP browser and trap receiver.

Central Manager Central Manager connects to Front-End via TPC/IP, and centralisesdata collection from one or more Front-End, makes collected dataavailable for HMI displaying. A single Central Manager can connectmore Front-ends. Central Manager contains a database (DSC), inwhich all info from Front-Ends are stored; each single piece ofinformation is called a “tag.”

On system start-up, Central Manager loads the database containingall tags to be monitored and commanded, detects which Front-End isin charge of values delivering for each point, and opens both a monitorand a command Client connection to all Front-Ends to be reached.Central Manager continuously receives tag value changes from Front-End.

Central Manager receives HMI commands to be sent to theequipment through the relevant Front-End. It performs auxiliaryfunctions on the collected data (e.g. elaborations, graphical display of analog data, etc).

Human Machine Interface The HMI functions allows the operator to interact with equipmentthrough a common and uniform interface. HMI shows a set of graphicpages with pop-up menus to allow browsing inside the M&Csystem. Operators are identified and authorised to work on thesystem, and interaction with equipment may vary according tooperator privileges. HMI allows operators to get quick anomalydiagnosis to detect the equipment or the condition responsible forthe station malfunctioning; fault analysis is eased by highlighting

Typical TT&C Antenna


Military/Aerospace Case Studies60 TELESPAZIO

equipment symbols on the graphic interface. A list of current alarms is shown to be acknowledged by operator. HMI allowsanalog variable trends to be shown on operator request.

Hardware Architecture M&CVIEW runs on a variety of hardware platforms – Front-End,Central Manager, and HMI can be installed on a single platformor distributed on different platforms. Central Manager and HMI need DSC run-time presence and can be run on Microsoftoperating systems. Front-End can run on all LabVIEW-supportedplatforms. M&CVIEW can be configured both in redundant or non-redundant configuration.

Current Installation And OnGoing Configuration M&CVIEW has been installed and configured for management of the Telemetry Tracking and Control Station for an european satelliteprogram for Earth observation. Telespazio is responsible for the core ground system integration. M&CVIEW performs its standardequipment monitoring and implements automatic station configurationto allow tracking and telemetry reception during satelittes passes.

M&CVIEW is currently under configuration activities for a nationalsatellite program for secure military communications. The system isbased on innovative technologies that enable the satellite to adaptpromptly to changing emergency conditions. Telespazio is responsiblefor satellite control centres, and M&CVIEW will be used to control fiveTT&C stations – both primes and backups.

M&CVIEW is also under configuration activities for SARC program(Satellite Access for Road Control). SARC is a powerfull TCP/IP digitalvideo-based surveillance system for National Highways; it makes useof advanced tecnologies for telecommunications, video acquisition andanalysis. It works through a fixed and mobile units network whoseconnections are on fiber optic, wireless, mobile phone system and satellite.

Telespazio is prime contractor in SARC, and M&CVIEW will allowoperators at the control centre to manage SARC equipment deployedin network nodes.

HMI Example


The United States Army Uses LabVIEW to DevelopNext Generation Night Sky SpectrometerRoy Littleton – United States Army RDECOM CERDEC,

Night Vision and Electrical Sensors Directorate

THE CHALLENGEDeveloping a remote spectrometer for next generation, low lightlevel electro-optical imaging systems.

THE SOLUTIONUsing National Instruments LabVIEW as the basis of a systemcapable of characterising the natural spectral irradiance of thenight sky at ground level.

At the U.S. Army Night Vision and Electronic Sensors Directorate(NVESD), we specialise in research and development of night visionand other sensor technologies.

The spectral intensity of the night sky is critical for thedevelopment, characterisation, and deployment of nighttime passiveimaging systems operating in the visible (0.4 to 0.7 µm), near infrared(0.7 to 1.1 µm), and/or shortwave infrared (1.1 to 2.5 µm) spectrum.Typical passive, low-light-level imaging sensors are generally signal-to-noise limited at a given night sky illumination condition ranging fromfractional moon, through clear starlight, down to overcast starlight.

The performance-limiting factor for most of these systems is thelow amount of available natural scene flux within the operationalspectral band of the system and the system's efficiency to convertthese low signal levels relative to its fundamental noise floor. Thedominant natural sources of night sky irradiation include the moon,airglow (or nightglow), tropospheric thermal radiation and direct andscattered radiation from stars and Zodiacal light. Sources ofatmospheric attenuation include absorption, scattering and turbulence.

The difficulty in determining night sky spectral irradiance for anygiven condition is the inherent variation of the individual sources andattenuating mechanisms as well as the angular dependencies relativeto the zenith that can also affect the irradiance from individual nightsky sources.

Night Sky IrradianceThe atmosphere is divided into six layers that contain various gases and particles, which decrease in temperature and pressuredepending on altitude. The first layer, the troposphere, extendsfrom the ground to about 11 km and contains the most significantattenuators, including water, carbon monoxide, clouds, fog, andaerosols. This layer is the dominant source of thermal backgroundradiation at wavelengths >2 microns. The troposphere has thehighest pressure of all the atmospheric layers and thus contains the highest density of particles which in turn produces the mostscattering of light. Above the troposphere is the stratosphere,extending to approximately 50 km. The stratosphere contains O3

(ozone) which is highly absorbent to ultraviolet radiation. Betweenthe next two layers, the mesosphere and the ionosphere, whichextend to 90 km and 300 km respectively, OH-airglow emissionsoriginate, and contribute appreciably to the night sky irradiance.Beyond the ionosphere are the thermosphere and exosphere.

Each of the six atmospheric layers contributes in some degree to the total observable ground level night sky irradiation in terms oftransmission, absorption, scattering and even emission. The dominantnatural illumination sources on a clear moonless night include airglow,starlight and galactic radiation from space. Airglow is comprisedmostly of hydroxyl ion (OH-) emissions which varies with zenith anglebut is azimuthally symmetrical. These emissions are due to vibrationaland rotational transitions of OH- at an altitude range of 70 to 110 km,producing energy in several bands. These bands, called MeinelHydroxyl Bands, contribute significantly to the night sky irradiance,especially above 1 micron. Beyond 2.5 microns the contribution of thehydroxyl emissions is even greater. However, it becomes relativelyinsignificant compared to the background thermal radiation providedby the troposphere.

Direct and scattered radiation from stars, primarily from the Milky Way, is considered anisotropic across the sky. Galactic radiation,or Zodiacal light, is sunlight scattered by interplanetary dust andtherefore contributes more in the visible and near infrared than in the shortwave infrared.

Night Sky SpectrometerThe Night Sky Spectrometer or NSS System uses a gratingspectrometer to collect spectral irradiance from a diffusereflectance panel from 400 to 2,000 nm with an effective resolutionof <25 nm and a sensitivity of ~10-9 W/cm2/µm. The system ishoused in an environmentally controlled enclosure with two solid-state thermoelectric air conditioners that helps keep the interior at nominally 22 °C while also reducing any excess moisture. Theremote accessibility is possible through a portable satellite systemfor system control and data transfer and allows the NSS to collectcontinuous spectral scans over several months unattended.

Products:NI Data AcquisitionDigital I/OLabVIEW

LabVIEW FPGA ModulePXI/CompactPCI

ni.com/aerospace 61United States Army RDECOM CERDEC

Screenshot of the LabVIEW Front Panel for the Night Sky Spectrometer


We developed a custom LabVIEW virtual instrument to be thebackbone of the NSS system. The internal computer contains two PCI boards; an NI PCI-GPIB card and an NI PCI-6036E multifunctionDAQ board that communicates with each of the hardwarecomponents. At the start of each scan, the VI reads the GPScoordinates from the satellite dish to access the current weatherconditions from the nearest NOAA weather station and inserts theinformation along with the temperature and relative humidity fromthe system’s own sensors into the header of the data. The VI thenselects the appropriate detector channel, detector gain, wavelength,filter, and grating for each data point. The VI then acquires thechopper and detector signals and calculates the intensity using acustom lock-in amplifier subVI. The VI also includes images fromthe two external webcams, reads the detector temperature,controls external LED indicators, and even e-mails the data sets.

The NI software and hardware communicates using two GPIBdevice addresses, 16 analog input channels, two analog output

channels, and eight digital input/output channels, which account for every available channel of the PCI-6036E. The VI has threemodes: scan mode, noise measurement mode, and laboratoryrecalibration mode.

For more information, contact:Roy LittletonUnited States Army RDECOM CERDEC, Night Vision and Electronic Sensors DirectorateFort Belvoir, VA USATel: (703) 704-0202E-mail: [email protected]

Military/Aerospace Case Studies62 United States Army RDECOM CERDEC

“We developed a custom LabVIEW virtual instrumentto be the backbone of the NSS system.”


63ni.com/aerospace

Using LabVIEW to Rewrite the Softwareof an Electronic Warfare Simulator

United States Army

Stephen Abbott – United States Army

THE CHALLENGEUpgrading software of an electronic warfare simulator used by theU.S. Army to test electronic warfare systems against radar threats.

THE SOLUTIONUsing the graphical programming environment and instrumentationcapabilities of NI LabVIEW to quickly rewrite the system’s control software.

Products:RFPXI/CompactPCILabVIEWPCI-GPIB

Testing Against Radar ThreatsWe at the Intelligence and Information Warfare Directorate of the U.S. Army Communications Command in Ft. Monmouth, New Jersey,provide a facility to test electronic warfare systems against radarthreats. We perform these tests either by radiating the threat signalsinside an anechoic chamber or directly injecting them into theelectronic warfare systems themselves.

To aid in testing, we designed and developed the ElectronicWarfare Simulator (EWSIM), which consists of integrated softwareand hardware that provide a realistic simulation of radar signalcharacteristics to simulate radar environments relative to the receivingantenna of the system under test. Using multiple RF sources, we cangenerate both pulse and continuous wave simulation. A programmablesignal simulator provides simulation of the emitter pulse, antennascan, and pattern characteristics. The RF Distribution Matrix controlsfour emitter signals and outputs eight quadrature ports (two peremitter) providing angle of arrival and range characteristics. UsingEWSIM, we can create threat scenarios and process them throughintegrated aircraft survivability equipment and other electronicsurvivability platforms.

Short Development TimeWe originally wrote EWSIM in C and operated it in DOS. We neededto upgrade the software to work in a modern Windows operatingsystem environment while using the existing RF and NI hardware. We chose NI LabVIEW because of its graphical programmingenvironment and instrumentation capabilities, and we gained a shorter development time rewriting the controlling software inLabVIEW than we would if we had modified the existing software.

Multifunction SoftwareThe controlling software of EWSIM consists of a multiscreen programthat creates and executes emitter simulations determined by user-generated parameters. We programmed the software to construct and store a database of these user-defined parameters, which are sent to the hardware during simulation that we run using a NationalInstruments PCI GPIB card.

Additionally, the software simulates a real-life scenario thatinvolves entering the path of motion of the system under test, along with the location of multiple emitters to act as threats. As the system under test moves through the scenario, the softwarecalculates the angle of arrival and range of the incoming threatsignals. The software then takes this data and programs the RFmatrix to the appropriate values, and also programs the emitters to simulate the correct radar mode.

Ability to Upgrade QuicklyIn addition to its instrumentation capabilities, the flexibility ofLabVIEW and its ability to reprogram also made it an attractive optionfor us because we plan to eventually upgrade the system’s hardwarewith a new synthesiser. At that time, we can access the newLabVIEW hardware driver either from the vendor or the NI Web site,ni.com, and quickly swap it into the software for the old driver.Because of the modular nature of LabVIEW, when we reconfigureEWSIM, we can easily reuse code during the software upgrade.

Most recently, EWSIM has proven instrumental in testing of theSuite of Integrated Radio Frequency Countermeasures (SIRFC) system – an RF electronic countermeasures and situationalawareness used on Army helicopters. Using National Instrumentssoftware and hardware, we could quickly upgrade the EWSIMhardware in time to help us with this project.

For more information, contact:Stephen AbbottU.S. ArmyBld. 600Ft. Monmouth, NJ 07703Tel: (732) 427-3671Fax: (732) 532-5570

“We chose NI LabVIEW because of its graphical programming environment and instrumentation capabilities, and we gained ashorter development time rewriting the controlling software inLabVIEW than we would if we had modified the existing software.”


Military/Aerospace Case Studies64 V I Engineering

The UUTs tested were transmitter PCB, receiver PCB, receiverassembly, and transmitter assembly. Some tests required an anechoicRF chamber to exclude RF interferences. Several instruments wereused in the test stand (RF signal generator, RF spectrum analyser,power supplies, digital volt meters, pressure transmitters, opticalencoders) and were controlled by the computers using GPIB or RS232 communication. In addition, the stands required relay controlfor activating solenoids and switches and this was accomplished usingPC-ER16 relay devices. Digital I/O cards were used to read/writeEEPROM data in the receiver and transmitter PCBs. All standsincluded bed-of-nails fixtures or clamping fixtures for mounting theUUT and providing access to the electrical input points and test pointson the UUT. The transmitter assembly test stand used IMAQ Visionsoftware, and IMAQ hardware and cameras for testing LCD screen on the UUT.

RequirementsSome important requirements for all test stands were ease of use,automatic test sequencing, user-configurable test sequence, testlimits, test parameters, and test branching, user-configurable multiplesecurity levels with corresponding function levels, self-diagnostics,user-configurable maintenance scheduling, monitoring, and logging. In addition, each test stand had its own test requirements.

Project Management and Software DesignProject management was important because of the strict deadlines,short development period, design changes, involvement of a largeteam of people, and multitude of custom and standard hardware fromseveral vendors.

Therefore V I Engineering (VIE) developed a comprehensive projectplan outlining all major software tasks, hardware delivery dates,resources and deadlines and created a project schedule based on their dependencies. VIE created a design document and a softwarearchitecture document for each of the test stands. The designdocument defined the test sequence and individual tests for each test stand. It served as a scope of work document and was providedto the customer. The software architecture document described thetest sequence and tests in more detail. It served as a developer’sreference document and was provided to the VIE’s project team. Itidentified test VIs, test subVIs and common subVIs to be created, and driver subVIs to be used. It defined the terminology and softwareconventions to be used so that all the team members could createsoftware in a consistent manner.

The choice to use LabVIEW Test Executive was an obvious one asit satisfied many of the requirements. Although NI’s Test Stand ismore powerful, we selected Test Executive because it was easilycustomizable. We enhanced the Test Executive with several newfeatures such as user-configurable security and function levels, user-configurable test parameters, preventive maintenance schedulingand logging, enhanced test report and error messaging capabilities,and diagnostics. Figure 1 shows the Test Executive operator interface screen.

For each test stand, the test sequence was broken down to aseries of tests which were developed as individual LabVIEW test VIs.These LabVIEW test VIs were created using VIEs state queuesoftware architecture. This was done by first breaking down each testinto a series of steps, and then assigning each step to a state in thestate queue. Additional steps were created for pre-test and post-testoperations and were integrated into the state queue. AdditionalLabVIEW VIs were created for pre-UUT, post-UUT, pre-UUT-loop, and post-UUT-loop operations and integrated into the test sequence.

A typical test sequence is as follows:n The operator scans the UUT using the barcode scanner

to read in the UUT’s ID.n The software checks the main database to see if the

UUT has passed all previous up-stream test stands.n The operator places the UUT in its fixture and closes the door

of the chamber. A switch on the chamber’s door initiates the automatic test sequence.

n The software then proceeds through the test sequence by controlling instruments. The software displays the PASS or FAILbanner to the operator.

Transmitter PCB Test StandThe test stand was designed to perform a test sequence of 6 tests.The main components of the transmitter The main purpose of the teststand was to verify components and functions of the transmitter PCB.The transmitter PCB is powered by the power supply, and electricalcontacts are controlled by relays. By controlling the electrical contacts,the transmitter PCB is operated in factory test mode, where ittransmits RF messages. The RF transmission is received by the patchantenna and demodulated and analysed by the spectrum analyser.

There were tests to verify RF carrier strength and frequency,demodulated signal frequency and duty cycle, and so on. At the end of the test, data is written to the transmitter PCB’s EEPROM usingdigital outputs. relays. By controlling the electrical contacts, thetransmitter PCB it transmits RF messages. The RF transmission isreceived by the patch antenna, and is then demodulated andanalysed by the spectrum analyser.

Products:LabVIEWLabVIEW Test Executive RF

High-Speed Digital I/OIMAQ Vision

Radio Frequency Test Stands for Remote ControllersSundaram Raghuraman – V I Engineering

THE CHALLENGEDeveloping four test stands for production testing of radiofrequency (RF) remote control components.

THE SOLUTIONUsing LabVIEW and LabVIEW Test Executive to rapidly develop the software by concentrating on individual tests instead of thetest sequencing architecture and user interface.


ni.com/aerospace 65

Receiver PCB Test StandThe test stand used was designed to perform a test sequence of 12 tests. The purpose of the test stand was to verify various sub-assemblies and components and also specific functions of thereceiver PCB. The receiver PCB is powered by the power supplies.The signal generator sends RF commands via the patch antenna tothe receiver PCB to perform required tests. The data from the receiverPCB’s EEPROM are then read by the optical encoder. We performedseveral tests to verify power-up time, power-up voltage, motor circuit,fan circuit, error codes, RF sensitivity, shut-down time, and so on.

Receiver Assembly Test StandThe test stand used was designed to perform a test sequence of twotests. The purpose of the test stand was to both calibrate the receiverassembly and perform an operation check. The signal generator wasused to send RF commands to the receiver assembly and used tocontrol its operation. The receiver assembly valve motor wascalibrated for different pressure levels by stepping it from high to lowpressure. The software then performs an op-check by verifying thatthe receiver assembly reaches the correct pressure level for eachcalibrated position.

Transmitter Assembly Test StandThe test stand was designed to perform a test sequence of 10 tests.The purpose of the test stand was to verify the operation and imagequality of the LCD screen on the transmitter assembly. The image onthe LCD screen was acquired using the cameras and IMAQ hardware.The transmitter assembly was operated in several factory test modes,by pressing appropriate buttons using solenoids on the clampingfixture. There were tests to verify 7-segment LCD characters (verticalsegments, 8’s, and horizontal segments) and also check for icons andpatterns. In addition there were tests to verify that data was storedcorrectly in the EEPROM by viewing it on the LCD screen.

ConclusionThe RF test stands had more functionality, robustness, andconsistency by using the Test Executive than would have beenotherwise possible within the short time available. Diligent projectplanning and management allowed accelerated development by usinga large project team. The systems were tested for repeatability, andperformed as required.

AcknowlegmentsVIE would like to acknowledge the many suggestions andcontributions made to the systems by Robert Zak, Brent Chiang,Bruce Hill of Honeywell Inc. We would also like to thank Stan Caseof V I Engineering for the most of the features of the enhanced Test Executive.

V I Engineering

“The RF test stands had more functionality, robustness, and consistency by using the Test Executive than would have been otherwise possible within the short time available.”


Military/Aerospace Case Studies Notes66


ni.com/aerospace 67Acquired Data Solutions

Ellen Byington – Acquired Data Solutions

THE CHALLENGEAutomating safe and reliable high-pressure, high-temperature, and high-load motion test procedures for aircraft components.

THE SOLUTIONDeveloping a rugged, safe, and automated data acquisition systembased on LabVIEW that incorporates National Instruments FlexMotionhardware and a programmable logic controller (PLC).

Our client, Perkin Elmer Fluid Sciences (formerly EG&G PressureSciences, Inc.) builds components for aircraft manufacturers such as McDonnell Douglas, Boeing, and General Electric. In the past, they had performed threshold tests on the components using manual test stations.

These tests took a long time to run and required constantsupervision. Safety, accuracy, repeatability, and customer satisfactionmotivated the company to seek an automated approach to performingthe tests. Using National Instruments LabVIEW, FlexMotion, and the SQL Toolkit, ADS designed an unmanned test station for dataacquisition that centered on a PLC. With this system, the operator can monitor the data and present customers with easy-to-read reports. Also, technicians have the ability to remotely run theirpressure tests from the laboratory, their desks, or anywhere outside the containment enclosure.

Building the Acquisition SystemAn incident during a typical high-pressure test prompted Perkin Elmer Fluid Sciences to build a containment enclosure around thetest stations. Although an enclosure increases safety, it also makesthe technician’s job of continuously monitoring and adjusting themechanical components within the station (mechanical relays,pressure, temperature, and more) increasingly difficult. In addition to safety concerns, Perkin Elmer Fluid Sciences wanted to improvethe accuracy of the tests and provide clients with reliable, easy-

to-read reports. Wetightened tolerancesusing automatic datacollection instead ofmanually reading from gauges. Also,handwritten reportswere no longeracceptable to many of Perkin Elmer FluidSciences customers.

Perkin Elmer Fluid Sciences hired ADS to provide direction andassistance in developing a data acquisition (DAQ) system that couldautomatically operate outside the test station enclosure. To meetthe need for an unmanned test station, we designed a system that centered on a PLC. A PLC has a low failure rate in industrialapplications and can control several critical functions such ascollecting sensor data and controlling relays to open and closepressure valves. Using NI LabVIEW software, we wrote anapplication to remotely monitor data collection from the PLC in

real-time through an RS232 serial protocol. Theapplication also permits technicians to entermanual inputs that are not gathered by the PLC.In case of a system failure, the application shutsdown the test and puts the system into a safemode. Upon failure, the application dials abeeper that contacts an off-duty technician.

Part of Perkin Elmer Fluid Sciences test procedures requiredmoving fixtures in high-pressure and high-temperature cycles. We incorporated an NI FlexMotion board with an AC servo motor. This high-performance board generates enough current to producethe high force required for precisely moving the fixtures. With theflexibility of this board to change the feedback loop, it is easy to switchtesting modes between distance and pressure. You can make thesechanges from software on-the-fly without changing any hardware andcables. We used the NI SQL Toolkit to pass sensor data to a MicrosoftAccess table for further analysis and report generation. We can noweasily transfer the data in the table to other Microsoft Office productssuch as Excel and Word.

Benefits of the SystemThis integrated approach provided a turnkey solution that met therequirements set forth by Perkin Elmer Fluid Sciences, Inc. Thesystem is secure and self-contained, and the operator can monitor the data. It also presents the customers with easy-to-read reports.Technicians now have the ability to remotely run their pressure tests from the laboratory, their desks, or anywhere outside thecontainment enclosure.

For more information, contact: Ellen Byington, Senior ManagerAcquired Data Solutions, Inc.1225 Martha Custis Drive, C-1Alexandria, VA 22302Tel: (703) 379-5303Fax: (703) 379-5307E-mail: [email protected]

Acquired Data Solutions Uses FlexMotionand LabVIEW to Build Unmanned Test Stationfor Aircraft Components Testing

Products:Motion ControlLabVIEW

FlexMotionSQL Toolkit

“We incorporated the NI FlexMotion board and an AC servo motor.This high-performance board generates enough current to produce the high force required for precisely moving the fixtures. With the flexibility of this board to change the feedback loop, it is easy to switch testing modes between distance and pressure.”

Automated Test Equipment for Stress-TestingAircraft Components


Products:NI Data AcquisitionLabVIEWLabVIEW Real-Time

SummaryThe Euclid Space Telescope is an interferometric instrumentoptimised for the high-resolution optical surveillance, from ageostationary orbit, by means of the synthetic aperture technique.

In order to obtain the desired co-phasing, and then the desiredresolution, a complex metrology and control system is needed toensure the necessary stability of the optical configuration. Ademonstrator (called MIT, Michelson interferometer testbed) hasbeen integrated in order to validate two very critical systems ofEuclid Space Telescope for achieving the co-phasing condition and maintaining the fringe pattern stabilised in the Michelsoninterferometer instrument.

This article contains an overview of the Euclid Space Telescope,and a short description of MIT performances, and goal achievements.

The Euclid Space TelescopeMultiple Apertures Telescope configuration like the Euclid SpaceTelescope one provide a unique opportunity to achieve very largeaperture optical systems. The motivation for developing multipleindependent telescope apertures is to provide high-resolutionobservation from space, avoiding the practical limitations in the areasof large optics fabrication (and weight) and adaptive wavefront control.Multiple telescope optics can be much smaller than large monolithicmirror of equivalent diameter having “as first consequence” animprovement on the weight and encumbrance to be launched.

Michelson Interferometer with Fizeau-type combination opticalconfiguration has been selected to implement the synthetic aperturetechnique. The telescope configuration consists in an array of eightsub-telescopes and a beam combining telescope at the centre of thearray which collects the light incoming from the sub-telescopes andproduces the interferometric image on a focal plane. An optical delay line equalises the paths of the incoming wavefront from each sub-telescope to the focal plane where they are superimposed. An interference fringe pattern is formed on the focal plane with a good visibility when the optical path difference (OPD) between theinterferometer arms is kept within a fraction of the coherence length.

As as the OPD increases, the fringe pattern becomes more and moredegraded, i.e. its visibility decreases. This is related to the fact that theinterferometer does not operate at a single wavelength, but on a finitespectral band.

In order to form a fringe pattern with a good visibility, the opticalpath length (OPL) of the light beams travelling in the eight arms of the Michelson interferometer must be equalised within a fraction ofthe coherence length of the operational spectral band. For a properoperation of the Michelson Interferometer, the OPLs of the lightbeams travelling in the eight arms must be equalised within 100 nm.When this condition is achieved, the interferometer is “co-phased.”After the co-phasing condition is achieved, the telescope is ready toperform the observations. During the image integration time of thefocal plane, the OPD between the eight arms of the interferometermust be controlled within a fraction of the observation wavelength (i.e., OPDij < 10 nm), in order to avoid fringe “jumps” or significantvariations of fringe pattern phase with consequent losses of contrastin the resulting image. If such a case occurs during an observation, theresulting interferometric image would be completely blurred and theinformation necessary to reconstruct the original image of the targetwould be lost.

This interferometer is equipped with laser metrology systems, for the measurement of the optical path difference (in absolute and relative terms) between the interferometer arms, and with amotorised delay line for the control of this optical path difference. A control system elaborates the measurement of the laserinterferometer and sends commands to the delay line.

Military/Aerospace Case Studies Alcatel Alenia Space Italia68

F. Musso, F. Bresciani, L. Bonino, and S. Cesare –

Alcatel Alenia Space Italia

THE CHALLENGECreating a digital control system for a laboratory demonstrator of theco-phasing system of the Euclid space telescope to maintain theoptical path differences among the telescope arms under 10 nm at 1, a mandatory condition to ensure nominal satellite operations.This activity has been performed in the frame of the Euclid CEPA 9RTP 9.9 contract commissioned by the Western EuropeanArmaments Organization (WEAO) Research Cell.

THE SOLUTIONInterfacing the control algorithm, written in C++ language andembedded in a dynamic-link library, with NI LabVIEW using a CallLibrary Function Node to exchange data (measures from ADC andcommands to DAC) with an NI DAQ board.

Digital Control of a Michelson InterferometerTestbed Demonstrator for a Satellite Telescope

Figure 1. Metrology lines for Michelson interferometry


ni.com/aerospace 69Alcatel Alenia Space Italia

Laser interferometry is by far the best technique to measure longdistance variations. Several interferometric schemes are possible, butall of them are based on the interference principle: two or more lightbeams are generated by the same source, run different length pathsand eventually are recombined (summed) on a detector whichmeasures the intensity. The intensity on the detector is a function ofthe relative phase of the interfering beams which, being waves, caninterfere either constructively or destructively. From the analysis of theinterference signal one can get information about the path differencebetween the light beams. For measuring the variations of the lengthbetween the two arms of an optical interferometer, the choicenaturally falls on a laser interferometer of Michelson type.Theinterferometer includes two types of laser metrologies:n An absolute metrology system (developed by INETI institute,

Lisbon, Portugal), providing the actual value of the optical pathunbalance between the interferometer arms, with lower resolution;

n A relative metrology system (developed by Alcatel Alenia SpaceItalia, Turin, Italy), providing the variation (from a given initial value)of the optical path difference between the interferometer arms,with higher resolution.

Both metrology systems are optically interfaced with the opticalinterferometer prototype, and are electrically interfaced with thecontrol system that elaborates the commands for the delay line.

The role of the absolute metrology is to support the achievement of the Michelson interferometer co-phasing, consisting in the equalisationof the optical path lengths of the various arms within a fraction of thecoherence length, so that a good visibility fringe pattern is formed on the focal plane of the instrument.

The relative metrology provides the measurement of the OPLvariations, starting from a given initial value (the one achieved at theend of the co-phasing operation), that will be used by the controlsystem for freezing the fringe pattern (OPD 10 nm) through the fine stage of the motorised delay line. Relative metrology is based on a Michelson interferometer metrology and has a nanometer level resolution.

The OPD disturbances to be compensated during the targetobservation, derive from the deformations of the satellite structureunder variable thermal loads and vibrations generated inside thesatellite (for instance by the attitude control system) and propagatingtill the interferometer mirrors through the instrument structure.

The Co-Phasing System Laboratory DemonstratorCo-phasing system is the most critical aspect of the telescope design.In order to test and demonstrate the co-phasing system concept, i.e. equalise the OPL between the interferometer arms by acting on a one degree of freedom delay line, a laboratory demonstrator has been implemented. The MIT demonstrator, consists of asimplified, laboratory-sized optical interferometer prototype, realisedwith the same optical configuration typology of the high-resolutionsatellite telescope.

Since the concept of the co-phasing system is to control the OPDvariations between the telescope arms, the laboratory demonstrator ofthe co-phasing system is equipped of one control delay line (CDL) thatact on one (the primary) arm, tracking the OPL variation of the other

arm (the secondary) and one disturbance delay line (DDL) that act onthe secondary arm introducing an OPL disturbance with the samePower Spectral Density (PSD) as the foreseen disturbance PSDpresent on the satellite telescope. The performance of the laboratorydemonstrator shall be the same required for the satellite telescope.

Control delay line is made by two actuators: a coarse stagemotorised translator and a fine stage piezoelectric translator. Thedisturbance delay line is made only by a piezoelectric translator. Thecoarse stage is used to reach the co-phasing condition starting froma big OPD, i.e. 1 mm. The fine stage works only after the co-phasingcondition is achieved and is used to control and stabilise the OPDbetween the two interferometer arms.

Co-phasing control system uses only the relative metrologymeasure and drives the fine stage of the control delay line in a closedloop. The coarse stage delay line is driven in open loop directly by theoperator, which reads the necessary displacement to reach the co-phased condition on the absolute metrology monitor. Coarsestage actuator is interfaced with a portable computer by a RS232port. Software interfacerealised in NI LabVIEWsoftware is used to set all the necessary parameters for programming the actuatordriver and for setting thedisplacement commanded.The absolute position of theactuator is constantly plottedon a chart. The coarse stageactuator is commanded until a co-phased condition isachieved. In the next figurethe experimentalinterferograms at co-phased condition is shown.

Co-phasing control system hardware is based on a portablecomputer (Pentium 4 2.66 GHz with 2 GB RAM) linked by an IEEE 1394 port to a portable NI DAQPad-6052E port. Even if this type of DAQ board is not a real-time device, it is possible to close a digital control loop up to 1 ms control step (clearly not in a hard real-time performance).

The disturbance delay line actuator is also driven with the same DAQPad-6052E. A disturbance generation algorithm runs on the same portable computer in parallel to the control algorithm.

Figure 2. Experimental Interferogramsat Co-Phased Condition

Figure 3. Coarse Stage Delay Line Software Interface


Military/Aerospace Case Studies Alcatel Alenia Space Italia70

Two ADC channels and two DAC channels have been used. The two ADC channels acquire two signals coming from the relativemetrology electronic used to reconstruct the OPD variations. OneDAC drive the piezoelectric driver of the fine coarse of the controldelay line, and the other DAC drive the piezoelectric driver of thedisturbance delay line.

Control algorithm design has been performed following the model-observer based technique Discrete time state equations are directlyimplemented in a C language algorithm. The control algorithm routineis compiled as a dynamic linked library (DLL) and interfaced by NI LabVIEW using a Call Library Function Node for exchanging data(measures from ADC and commands to DAC) with an NI DAQ board.This solution allows testing of the control algorithm (written in Clanguage and very close to the final flight version) interfacing it veryeasily to the laboratory NI DAQ hardware without using flight-qualifiedhardware, saving a lot of time and money. Also the disturbancegeneration algorithm is implemented in discrete state equations and is written in C++ and compiled in a DLL. Figure 5 shows the controlsystem block diagram.

As our system is not a real-time system, a very simple softwareinterface was designed without chart/graphs in order to avoid loadingthe control algorithm execution. The software interface contains a set of buttons which are used to start and stop the relative metrology,

the disturbance generation algorithm, the control system algorithm,and a set of LEDs which indicate the status of the control system.

All the important control variables (measures, commands, statevariable, and so on) are stored in the computer memory and recordedin binary format on the hard disk at the end of the control session.

The test results are very good, the residual OPD has a σ ≈ 9.5 nmand fulfils the requirement. Figure 6 shows the OPD disturbancewithout control system (left) and the residual OPD with control system (right).

In order to improve the co-phasing control system performance, an upgrade of control system hardware is been foreseen. Nextdevelopment will be the reduction of the control step at 0.1 ms usingan NI Real-Time hardware and LabVIEW Real-Time software with aquite adjustment of the control software and control algorithm.

Figure 5. Control System Block Diagram

Figure 6. Control System Test Results

Figure 7. The Michelson Interferometer Testbed

70

Figure 4. National Instruments DAQPad-6052E Acquisition Device


71Averna/Thales Canada, Aerospace Division ni.com/aerospace

Hardware-in-the-Loop Made Easy by Using NI PXI and LabVIEW Real-TimeAverna/Thales Canada, Aerospace Division

THE CHALLENGECreating a hardware-in-the-loop platform with a deterministic looprate of 1,000 iterations per second; managing hundreds of I/Os;scalable to 2,000 channels without performance deterioration;integrating more than 10 nodes running device models in real-time;and sharing simulation and I/O data with a timing jitter of tenmillionth of a second. All to be achieved with strict deliveryschedule and high cost effectiveness.

THE SOLUTIONUsing multiple NI PXI chassis and a wide range of NI modules with analog and digital I/Os, along with ARINC-429 hardware integrated with efficient LabVIEW and LabVIEW Real-Time software developed on Microsoft Windows nodes, and PXI nodes networked by reflective memory boards and TCP/IP.

Aerospace and automotive design engineers have benefited fromcycle time reduction using hardware-in-the-loop facilities for manyyears now. Design models for the new products can be simulated athigh speeds and interfaced with input and output signals from existinghardware in real time, thus iterating and validating the design withunprecedented efficiency. As such systems are beginning to play amajor role in design activities, a new demand is being verified for costeffective implementation of very flexible and high performancehardware-in-the loop facilities. Capability to integrate multi-vendortechnology and use of off the shelf components is often dictated bytime, cost and maintenance considerations. National Instruments PXIand LabVIEW provide the ideal platform for conceiving such solutions.

Our customer, Thales Canada, Aerospace Division, innovativelyengaged in design of modern fly-by-wire controllers, needed astrategic renewal of their design validation facility using hardware-in-the-loop system. The system was required to deterministicallyintegrate several hundreds of data channels and a system composedof device models executed on more than ten computing nodes.Interdependency of these multiple nodes would also require that anycomputed or acquired data be transmitted, system-wide, with a verylow latency of 10 ms. To capture any system transients, a loop rate of1 kHz was needed to synchronously acquire all input signals, updateall outputs and step through the model computation.

Compatibility of new hardware-in-the-loop facility for futureproducts required a very flexible system with dynamic association ofhardware resources to physical signals, scalability to 2,000 channelswithout any performance deterioration and rugged sanity checks of system integrity while being configured for new test set-ups.

The solution also required an exhaustive logging of all data and an equally flexible and dynamic real-time graphical and tabular data viewing through multiple access controlled computers.

Thales Engineering team elaborated all performance requirementsand outsourced the system technical design and implementation toAverna Technologies. Averna’s solution to this challenging set ofrequirements is presented below.

System DesignA strict delivery schedule of five months, and a competitive cost-effectiveness requirement, added further constraints to the design ofthis already technically challenging system. The National InstrumentsPXI product line was identified as a natural and excellent platform to implement the system. The availability of embedded real-timecontrollers, the wide range of NI modules for analog and digital I/O,openness to third-party vendors for ARINC-429, reflective memoryand IRIG-B synchronisation boards, along with rapid softwaredevelopment made possible by LabVIEW and LabVIEW Real-Time,and were essential parts of the engineering elegance of solutionshown in the following high-level architecture.

Products:NI PXIPXI Real-TimeLabVIEWLabVIEW FPGA Module

LabVIEW Real-TimeReal-Time Execution Trace Toolkit

R Series Data Acquisition

Figure 1. PXI-Based Hardware-in-the-Loop System

Figure 2. Virtual Instruments for System Configuration


Military/Aerospace Case Studies Averna/Thales Canada, Aerospace Division72

Signal Conditioning and Data AcquisitionGiven the varied and custom nature of signals originating from fieldtransducer LVDTs and RVDTs, a custom signal conditioning hardware was designed and implemented to amplify the signals and provideisolation, along with synchronised sample and functionality. Theconditioned signals are wired to National Instruments I/O moduleshoused in multiple PXI chassis. The PXI platform provides thenecessary modularity and system scalability, along with precise timingsynchronisation and distribution of real-time clock. In the early phasesof system development we successfully verified that a fully populatedPXI chassis could perform full-speed data acquisition at 1 kHz withoutcreating any throughput bottlenecks. Throughput and determinismchecks were also successful for TCP/IP, reflective memory and evenincluding CPU interrupt times making critical design review of system;a great success.

Application SoftwareSystem configuration is stored in a Windows database of tag names,hardware channel association, acquisition rates, engineeringconversion, and system calibration information.

LabVIEW allows composing hardware resources and databaseinformation into system configurations targeted for specific devicetests. Once composed, the configuration is checked for systemintegrity and throughput requirements and downloaded to embeddedtargets running LabVIEW Real-Time on PXI nodes.

LabVIEW Real-Time initialises the entire system and uses PXItiming module to synchronise all PXI nodes. Averna developed acustom FPGA personality code for the NI PXI-7831R module forgenerating IRIG-B synchronisation signal to ARINC transceivermodules with the PXI clock. The time-critical code on PXI real-timecontrollers now handshakes with signal conditioning hardware anddeterministically acquires the input signals and updates outputs; all I/O taking place at the same clock edge.

Simulation nodes run The MathWorks, Inc. Simulink® device models on more than 10 desktop nodes. All PXI and simulationnodes share the data and execute system commands through areflective memory network that ensures a low latency of 250 nsfrom node to node. A custom command interpreter was developed,using LabVIEW Real-Time, that provides remote CPU interrupt and procedure invocation capabilities through reflective memory. LabVIEW Real-Time and PXI also interface with a number of ARINC-429 transceivers, providing extensive communication, word definition and ARINC pollution capabilities with some of the related virtual instruments shown below in Figure 3.

System MonitoringAll test data is transferred in real time to remote node for disk storageusing a static reflective memory ring buffer. Transferred data is nowmade available to multiple monitoring nodes that can view the real-time data as well as logged data for test analysis. A number ofvirtual instruments based on LabVIEW allow engineers to flexiblydefine the graphical and tabular data viewing displays as shown in Figure 4.

ConclusionThe presented solution successfully integrates diverse technologyproducts while being highly modular and scalable to thousands ofchannels by adding more PXI chassis in the system.

PXI, LabVIEW and LabVIEW Real-Time were the key factors ofmaking this flexible, high-throughput, low-latency, hardware-in-the-loopsystem a remarkable success, while saving more than $200,000 USDin implementation costs and several months on development time.

For more information, contact: Sonia D’EliaCommunications and Marketing CoordinatorAverna 87, Prince Street, Suite 140Montréal, Québec H3C 2M7Tel: (514) 842-7577Fax: (514) 842-7573E-mail: [email protected]

Figure 4. Graphical and Tabular Data Viewing Capabilities

Figure 3. Virtual Instruments for ARINC Word Definition and PollutionSimulink® is a registered trademark of The MathWorks, Inc.


73BAE Systems Avionics ni.com/aerospace

BAE Systems Develops Field-Orientated Control ofa Three-Phase Brushless Permanent Magnet MotorBrian Mann – BAE Systems Avionics

THE CHALLENGEDeveloping rapid prototyping for the next generation of high-performance motor controllers.

THE SOLUTIONUsing the NI PXI platform, LabVIEW 7 Express, LabVIEW 7 FPGAModule, and PXI-7831R reconfigurable I/O modules to implement a fully digital motor controller on a Xilinx FPGA.

Products:LabVIEWLabVIEW FPGA PXI/CompactPCI

Next-Generation Motor Controller Design BAE Systems Avionics designs and manufactures electronic warfareand surveillance systems. To remain competitive, the Avionics divisioncontinually evaluates new tools and techniques to reduce lead-time onnew technologies. The hardware in our labs and the software in whichwe invest our time are key to our continued success.

Field-orientated control (FOC), or vector control, is an emergingtechnology that promises improved torque-speed characteristics froma wide variety of motors, and most of our products incorporate at leastone DC motor. The Servo Systems Technology Group at BAE Systemsin Edinburgh is interested in increasing peak power because upgradedmotor drives would squeeze extra performance from existing motorsand save weight in avionics products by reducing the motor mass innew designs.

Moreover, as FPGAs increase in capacity, we can use FPGAs notonly for motor control, but also for full servo system control. We usedNational Instruments products to create a rapid prototyping route thatsignificantly reduces new-technology risk early in the design life-cycle.

The FOC Technique Motors driven by traditional square-wave amplifiers suffer from poortorque-speed characteristics and torque ripple caused by commutationerrors. Sinusoidal commutation solves the torque ripple problem andworks well for low motor speeds. At higher speeds, the PI currentcontroller must track a sinusoidal current with increasing frequencywhile overcoming a Back EMF of increasing frequency and amplitude.This causes a phase lag, which results in a loss of torque per ampbecause the torque producing flux is not acting at 90 degrees to the rotor. This effect is exhibited by the curve of the torque-speed (TS) plot.

Essentially, the TS plot comprises two lines – the horizontal line, which is the volt limit that governs the maximum speed, and the vertical line, which is the current limit that determines themaximum torque.

We used FOC to improve the TS characteristics. This commutationmethod uses transforms to convert the sinusoidal currents andencoder position into the rotating rotor d-q reference frame. The d and q components are DC and, therefore, easily controlled by a

PI controller. The resultingcontroller output is subject to aninverse transformation thatproduces voltage waveforms ofthe correct phase and amplitudeto maintain the flux at 90 degreesto the rotor for maximum current-to-torque power conversion.

Space Vector Modulationand FPGA Implementation With full digital control, we coulduse space vector modulation (SVM) to unlock 15 percent more no-load speed. FOC control made this possible because we wereno longer restricted by the classical commutation limits of busvoltage/2. The trigonometry of SVM changed the relationship tobus voltage/Ö3 based on a triangle of angles 30, 60, and 90; andsides 1, 2, and Ö3. From this ratio, we calculate that bus voltage/2divided by bus voltage/Ö3 equals 1.1547, or a 15 percent increase.

Traditional FPGA control strategy implementation can involvesignificant risk because the first physical realisation occurs towardthe end of the design life cycle. Through rapid controller prototypingwith the National Instruments LabVIEW FPGA Module, we could

test and further develop on real hardwareeven before we started FPGA design.

Algorithm development starts with mathematical modelling packagesincorporating fixed-point block sets tosimulate FPGA math capabilities. We could

immediately rewrite the fixed-point algorithm in G code and run it onthe National Instruments PXI platform or CompactRIO reconfigurablecontrol and acquisition platform. Hardware description language (HDL)generation, logic synthesis, HDL simulation, and place and routeactivities are fully automated into the compilation process. The VHDLis loaded to the Virtex XC2V1000 on the NI PXI-7831R via thebackplane of the PXI chassis. The PXI-7831R provides eight 16-bitanalog-to¬digital converters, eight 16-bit digital-to-analog converters,and 96 transistor-transistor logic I/O pins for easy hardware connectionvia a plug-in terminal card.

Debugging was easy because we could sample data from anyFPGA register and display the results on our host PC running NI LabVIEW without disruption to FPGA execution.

Rapid System Component Prototyping The rapid prototyping system we used to investigate this newtechnology included a PXI chassis, which hosts a NI PXI embeddedcontroller running LabVIEW software, and the PXI-7831Rreconfigurable I/O module. We used the LabVIEW graphical

“Through rapid controller prototyping with the National InstrumentsLabVIEW FPGA Module, we could test and further develop on real hardware even before we started FPGA design.”

ACEIII Stall Currents


Military/Aerospace Case Studies BAE Systems Avionics74

development environment, and LabVIEW FPGA module, to developcode for all system parts. As described above, we configured andprogrammed the PXI-7831R FPGA on the host PC directly in theLabVIEW environment. Compiled LabVIEW code is downloadeddirectly to the FPGA. LabVIEW running under Windows on the hostPC provided system monitoring and visualization, again developedusing LabVIEW.

By using the National Instruments PXI-7831R FPGA, we havedemonstrated a new technology to our customer with minimal time and equipment investment. Without a VHDL learning curve,we created a 40 kHz real-time controller that far exceeds the single-point I/O capabilities previously available.

For more information, contact: Brian MannBAE SystemsServo Systems Technology GroupSensor Systems Division2 Crewe Road North Edinburgh, EH5 2XSTel: +44 (0)131 343 8791Fax: +44 (0)131 343 8941E-mail: [email protected]

“Debugging was easy because we could sample data from any FPGAregister and display the results on our host PC running NI LabVIEW without disruption to FPGA execution.”


75Cal-Bay Systems, Inc. ni.com/aerospace

Data Acquisition and Control Systemfor Testing Aerospace Fluidic ComponentsSorin Gramma – Cal-Bay Systems, Inc.

THE CHALLENGECollecting data from a few channels and controlling a few PID loopsare basic requirements for testing an aerospace fluidic device, such asa valve. But when the requirements are expanded to allow multipledevices to be tested in parallel, with over 120 channels of analog inputbeing sampled continuously, 32 or more PID control loops runningconcurrently and various digital trigger events being analyzed in real-time, the task of developing such a test system becomes non-trivial. Add to this the requirement of monitoring and controllingmultiple test setups in parallel over the network and you end up with a highly complex system.

THE SOLUTIONUsing National Instruments LabVIEW and the LabVIEW Real-Time Module running on a PXI controller, we developed a flexible test system that allows users to configure and run multiple test configurations in parallel using only one set of data acquisition and control hardware.

Whittaker Controls is a leader in the design and manufacture of a broad range of fluid control devices and systems for bothcommercial and military aircraft, as well as various industrialapplications. Their products regulate pneumatic (air), hydraulic (fluid) and fuel flows in aircraft systems, and are used in virtually all Boeing- and Airbus-manufactured commercial aircraft.

Their on-site testing facility is used intensively to performmanufacturing, acceptance and qualification tests. A DaytronicSystem-10 test system was used for many years to performthese tests in a semi-automated fashion, but as the testingrequirements became more complex and the system aged, it became necessary to replace it with a new, PC-based dataacquisition and control system.

Cal-Bay Systems, Inc. developed a turnkey test system to replace the functionality of the existing test system whileproviding additional enhancements to increase the test throughput and the productivity of the entire test facility.

Products:LabVIEWLabVIEW Real-Time

PXINI Data Acquisition

Figure 2. Example of an Aircraft Valve

Figure 1. Typical Test Setup Usedto Test a Valve

“Using NI LabVIEW and the LabVIEW Real-Time module running on a PXI controller, we developed a flexible test system that allows users to configure and run multiple test configurations in parallel using onlyone set of data acquisition and control hardware.”


Military/Aerospace Case Studies Cal-Bay Systems, Inc.76

Multi-Point Temperature Control System for Simulated Space Environment

Products:LabVIEW PXI SCXI NI Data Acquisition

Lockheed Martin Space Systems Company (LMSSC) tests satellite flight hardware in thermal vacuum chambers (see Figure 1).These systems simulate the rigors of space using a nitrogen-chilledchamber operating at 1x10-8 Torr vacuum.

After years of operation with an existing system that relied onunsupported, VAX-based hardware, Lockheed Martin needed a new system with improved test setup, operation, data logging, and hardware standardization. Additionally, the system had to berobust. The chambers are run 24/7 for extended periods, and anybreakdown could compromise the flight hardware.

Lockheed Martin engineers worked with National Instruments to design a dual-chassis PXI-based system (see Figure 2) that couldcontrol the thermal chambers and perform the necessary tests.Lockheed Martin then turned to Cal-Bay Systems, Inc. to make their design a reality.

Dave Wiesberg – Cal-Bay Systems, Inc.

THE CHALLENGEUpgrading the data acquisition and control systems for thermalvacuum chambers used to test satellite flight hardware.

THE SOLUTIONUsing NI hardware and LabVIEW software, the new system design replaced existing VAX-based hardware with a standardisedPXI system, resulting in a robust, flexible, and secure test environment for mission critical flight hardware.

Figure 1. Space Simulation Vacuum Chamber

Figure 2. Overview of Thermal Vacuum System

“Using NI hardware and LabVIEW software, the new systemdesign replaced existing VAX-based hardware with a standardised PXI system, resulting in a robust, flexible, andsecure test environment for mission-critical flight hardware.”


77Cal-Bay Systems, Inc. ni.com/aerospace

Aircraft Actuator Life Cycle Testing

Products:LabVIEWM Series PCI Data AcquisitionCompactDAQ

To test a new breed of electrical actuators, we decided we needed to automate the original manual process. With this automation, engineers could seed failures within the actuator to identify potentialfailure points. Previously, the duty cycle to drive the actuator was a simple sine wave generated by a waveform generator. The amplitude was varied to excite the actuator to various levels withinthe operating window of the actuator. This was left to cycle for various periods of time until the device eventually failed. This typicallytook months.

The measurements were taken from a number of sensors both internally within the actuator – for measurement of motortemperature – and externally for load, vibration, and actuatorresponse to the duty cycle.

HardwareWe developed the new automated system using LabVIEW. Thehardware included a high-speed NI M Series PCI data acquisitionboard to provide the duty cycle waveform and capture the higher-speed measurements. To confirm the hysteresis characteristics of theactuator, we monitored both the waveform output and the responseoutput from an external LVDT simultaneously using two of the dataacquisition board analogue inputs. These were plotted on the mainscreen as an XY plot, providing a visible indication of the hysteresisperformance. We also monitored the actuator power supplies usingSCC modules in the NI SCC-68 connector block.

With an accelerometer on the body of the actuator, we were ableanalyze motor vibration captured by a NI 9233 C Series modulemounted in the NI CompactDAQ chassis. The vibration measurementwas part of the analysis that helped predict the failure towards the end of the test cycle. We used a load cell with a charge amplifier tomeasure the load being applied to the actuator, which itself wasattached via a spring to a fixed mounting point on the test rig.

The actuator had an internally mounted thermocouple thatmonitors the motor temperature inside the device using an NI 9211 C Series module along with ambient temperature.

SoftwareOne of the key benefits of using LabVIEW was the ability to create anumber of duty cycles that represented more truthfully the operationof the actuator in the real world. Instead of just using a simple sinewave, we developed a complex set of duty cycles. We cycled theseindividual duty cycles one after the other and then repeated theprocess. Each duty cycle excited the actuator to a different level of extension, including one that set the actuator at full extension toreally test it to its limits.

The software GUI also provided the operator with the ability to view all of the measurements on trend type charts as well as digitaldisplays. All measured data was saved to file at one-minute intervalsfor future analysis. A limit was placed on some of the strategic inputsthat identified when the device was close to failure; these includedthe vibration channel, current output from the power supply, andinternal temperature of the device. If any of these channels roseabove the preset limit, the system started logging data at 10-secondintervals for a period of 10 minutes. If the inputs rose to a secondhigher level during this period, the system shut down by turning off the power supplied to the actuator automatically. During thisshutdown sequence, data was recorded and saved to disk at thefull speed of the data acquisition system to enable closer inspectionof the data during postanalysis of the failure. If the inputs stabilisedthen, the test would continue as normal.

A number of actuators were seeded with potential issues suchas grit in the gearing, cogs missing from the gearing, and so on tocheck how these issues affected long-term performance.

ConclusionWith this solution based on LabVIEW, our customer could test theactuators much more thoroughly than was previously possible. It also provided much better analysis of the actuator characteristics and performance in a significantly shorter time.

For more information, contact: Ian CrightonCal-Bay Systems Europe LtdSuite 2, 13 Fairlawn Liden, Swindon, UK SN3 6ETTel: (0044) 1793 538061Fax: (0044) 1793 538061E-mail: [email protected]: www.calbay.com

Ian Crighton, MD – Cal-Bay Systems, Inc.

THE CHALLENGEDeveloping an automated PC-based life-cycle test system toreplace a traditional manual-based system for life-cycle testing of aerospace actuators.

THE SOLUTIONProducing a fully automated life-cycle test system powered by NI LabVIEW software by using PCI data acquisition hardware for duty-cycle simulation and NI CompactDAQ hardware for sensor inputs.

System Overview


Military/Aerospace Case Studies Korry Electronics78

Using National Instruments PXI-CAN to MonitorAvionics Control Panels for the Boeing 787

At Korry Electronics, we needed a solution to test a family of controlpanels for the new Boeing 787 aircraft flight deck. We are working to meet an aggressive Boeing project schedule that is 16 monthsshorter than any previous Boeing airplane development project. The 787 systems, which feature an open architecture at the core, will be more simplified compared to existing airplanes and will offer increased functionality. One example is the health-monitoringsystems the airplane will use to self-monitor and report maintenancerequirements to ground-based computer systems.

In the aerospace industry, control panel suppliers are seeking a low-cost replacement to the ARINC-429 bus, and are migratingtoward a CAN-based solution due to higher bus speed and datapayload requirements. We needed a way to communicate with andmonitor multiple CAN buses on each unit under test for correct CAN data, and to transmit control data to adjust lighting and set otherpanel functions. We chose National Instruments LabVIEW, whichfeatures compatibility with NI PXI-CAN cards and ready-to-run NI LabVIEW driver libraries, to achieve the rapid development time the project requires.

The control panels transmit discrete digital switch data, and aunique data word represents each switch position. For control panelsthat contain rotary potentiometers and encoders, the data valuesincrease and decrease depending on the direction of rotation. CANdata words set all the control panel lighting levels and the controlpanel indicators with on/off commands. For production testing, wetested one control panel at a time. During qualification testing, weconfigured the NI PXI test system to allow for simultaneous testing ofmultiple control panels at the same time via CAN buses.

Hardware and System ArchitectureThe test system hardware consists of two NI PXI-8461/2 CANinterfaces installed in a PXI mainframe along with multiple relayboards, power supplies, and a DMM card. The system can monitor upto four individual CAN buses at once and test 100 percent discrete I/Oand DC power functions. Each control panel transmits a unique CANbus ID that is identified by using LabVIEW routines. The test systemcan thereby emulate the function of the CAN bus data concentratorused on the aircraft.

The test software, which we wrote entirely in LabVIEW, integratesNI-CAN drivers in custom subroutines to initialise CAN ports forspecific CAN addresses and perform CAN data frame read functions.We created additional subroutines to compare the received data to theexpected data frames. For each CAN bus session, the CAN and objectnetwork interfaces are opened and configured, followed by the CAN

read operations and then session closure. For lighting functions,specific CAN data is transmitted to the control panels. We wroteadditional programs to monitor switch positions in real time, andothers to monitor CAN data from each panel and write time-stampeddata to a log file for any changes detected.

During production test, we use NI TestStand to control testsequencing and test results reporting. The first step is to instruct theoperator to set each switch, rotary potentiometer, and encoder to aspecific position. A test software panel graphically illustrates eachswitch position of the unit under test. The second step is to create anHTML log file of any data discrepancies noted during test. For switchpanel indicators, we use a variety of test scenarios. One scenarioilluminates all of the indicators on the control panel and has theoperator visually verify that the correct indicators are lit up. We createdsubroutines to send a CAN message to the control panels for lighting,which can be controlled in real time by transmitting CAN data tocontrol brightness levels from no light to full brightness levels using a LabVIEW dial. In another scenario, the operator clicks on the testsoftware panel, which individually commands each indicator to light up by transmitting a CAN message to the control panel.

Conclusion and OutlookWe are successfully developing a family of complex CAN-basedcontrol panels for use on the Boeing 787 airplane by utilizing NationalInstruments software and hardware. We were able to quickly developnew test software using LabVIEW with almost unlimited control ofCAN bus data. The PXI-CAN cards have proven easy to configure andhighly reliable in operation. We plan on developing test equipment forfuture programs with short deadlines using National Instruments testhardware and software for many years to come.

For more information, contact: Allen Cutler, Korry ElectronicsTel: (206) 281-1300E-mail: [email protected]

Products:PXI-CANPXI/CompactPCI

NI TestStandLabVIEW

Allen Cutler – Korry Electronics

THE CHALLENGEDeveloping a CAN bus test system to interact with intelligentavionics control panels and communicate switch status, controlpanel lighting functions, and report panel status data such as partnumber and serial number.

THE SOLUTIONUsing National Instruments LabVIEW for rapid development time, NI PXI-CAN cards with ready-to-run NI LabVIEW driver libraries, and NI TestStand for production test sequencing and reporting.

Korry Electronics Harnesses the Power ofVirtual Instrumentation to Design ControlPanels for the Boeing 787 Dreamliner


79Lockheed Martin Space Systems Company ni.com/aerospace

Lockheed Martin Uses NI LabVIEW SimulationInterface Toolkit and PXI for Flight SimulationModel Development

Products:LabVIEWLabVIEW Real-Time Module LabVIEW Simulation Interface ToolkitPXI/CompactPCI

Creating a Precise SystemLockheed Martin Space Systems Company (LMSSC) is developingmicrosatellite technologies for autonomous rendezvous andproximity operations (ARPO). In support of near-term flightdemonstration opportunities, LMSSC began IRAD development ofspecialised software to control a scanning LIDAR as the primaryinstrument to support relative navigation for ARPO maneuvers.

We quickly realised the need for a real-time flight software testenvironment that would simulate the interaction between LIDARcontrol software (LCS) running on the main spacecraft CPU, and the LIDAR instrument. The spacecraft CPU, part of the IAU,communicates with the LIDAR instrument via synchronous andasynchronous RS422 serial protocol.

IRTE consists of LCS and an orbital dynamics simulationcontained in a NI LabVIEW wrapper, embedded on an NI real-timePXI system. LCS and the orbit dynamics model, both developed inThe MathWorks, Inc. Simulink® software, were easily integrated intothe LabVIEW application using LabVIEW Simulation Interface Toolkit.From there, we built RS422 I/O drivers into the LabVIEW applicationto allow serial communication with LRTE.

We followed a similar process to build LRTE. A LIDAR hardwaremodel, also developed in SimuLink, was contained in a LabVIEWwrapper with RS422 drivers. LRTE also received orbit simulation data and other simulation controls from IRTE via reflective memory(connected with fiber-optic cables).

The system proved to be very flexible; when we unexpectedlyreceived actual flight-like hardware, we were able to quickly adapt theIRTE/LRTE system to test the hardware. We successfully controlledthe actual LIDAR using IRTE and also successfully tested the actualIAU using LRTE. A duplicate of the LRTE was provided to the flightsoftware (FSW) development/integration subcontractor for installationinto the processor in the loop lab to support FSW requirementsverification and assorted mission simulation scenarios. In addition,

the system was easily controlled using the LabVIEW built-in Web-publishing tool. Using this tool, Lockheed engineers couldinterface to the PXI chassis from any desktop computer on thecorporate network.

LabVIEW Reduces Development TimeWe chose LabVIEW rather than traditional text based real-timedevelopment tools primarily because we believed the graphical natureof NI LabVIEW Real-Time would lead to faster system developmenttime with the small staff of engineers allocated to our project. Weused the LabVIEW Real-Time Module, LabVIEW Simulation InterfaceToolkit, and two real-time PXI systems to build complete IRTE andLRTE systems at a fraction of the time that would have been requiredwith traditional text based real-time programming. Although theproject presented various technical problems and multiple changes inrequirements, the LabVIEW graphical development environment andsupporting applications helped our team solve the problems andultimately deliver a robust and versatile product.

For more information, contact: Jesse HopkinsLockheed Martin Space Systems CompanyP.O. Box 179Denver CO 80201-0179Tel: (303) 971-6513Fax: (303) 971-8314E-mail: [email protected]

Jesse Hopkins – Lockheed Martin Space Systems Company

THE CHALLENGEBuilding a prototype integrated avionics unit (IAU) and a hardware-in-the-loop (HIL) simulator to test the light detection and ranging(LIDAR) control software functionality.

THE SOLUTIONDeveloping a real-time IAU controller prototype, or IAU real-timeemulator (IRTE), with the National Instruments LabVIEW SimulationInterface Toolkit and real-time PXI system as well as LIDAR real-time emulator (LRTE) to simulate the IRTE behavior and testing.

Simulink® is a registered trademark of The MathWorks, Inc.

“We chose LabVIEW rather than traditional text-based real-time developmenttools, primarily because we believed the graphical nature of NI LabVIEW Real-Time would lead to faster system development time with the small staffof engineers allocated to our project.”


Military/Aerospace Case Studies Mink Hollow Systems80

Edward Delaplaine – Mink Hollow Systems

THE CHALLENGEControlling the concentration of a chemical agent gas simulant in a simulant challenge test chamber while measuring temperatures,pressures, and penetration levels of a unit under test.

THE SOLUTIONUsing National Instruments Compact FieldPoint hardware to monitorand control the chamber. A laptop with wireless connection providesa user interface for control and datalogging while the LabVIEW Real-Time application maintains safe operating conditions.

Automated Control and Measurementof Chemical Agent Penetration

Products:Compact FieldPointLabVIEW

Protecting U.S. troops from chemical agents is of utmost importancefor the U.S. Armed Forces. To help achieve this goal, cutting-edge filters, filtration systems, and protective materials require rigoroustesting at the design and manufacture phases. Legacy chemical testchambers routinely require manual control and operation and loggingof data by hand. An essential element to facilitate testing goals is themodernisation and automation of these older chambers. Mink Hollowwas contracted by the Chemical Biological Center at the APG toupdate one such chamber using off-the-shelf hardware and customsoftware to control and monitor various user-configurable input sensors. Hardware requirements and low software development costled us to select National Instruments Compact FieldPoint hardwareand the National Instruments LabVIEW programming environment asthe system workhorses. With rapid hardware configuration and software development, we provided the Chemical Biological Centerwith a custom control system in a relatively short time within the constraints of a modest budget.

Concentration ControlVarious tests require controlling agent simulant concentration in thetest chamber to a specific level. To accomplish this, three outputs actin concert to pump, vaporise, and disperse simulant throughout thechamber. The first element, a powerful blower, is controlled withoutfeedback to disperse vaporised chemical. The blower provides thecritical airflow needed to pump and disperse the chemical, minimizingchemical gradients in the chamber.

Vaporisation of the simulant occurs when the pumped chemicalstream hits the second element, heating coils, at a specifictemperature. Thermal accuracy is critical because over temperaturecondition has the potential to oxidise and alter the chemical makeup,and an under temperature condition would not properly vaporise thechemical, a critical for proper dispersion. The heating coils arethermally controlled via a PID loop with thermocouple feedback. If thesystem detects that the heating coils are not heating, the chemicalpump is disabled as vaporisation cannot occur. The third controlelement, also PID controlled, is the chemical pump, which uses aconcentration sensor for feedback.

Tuning the three-output, two-controller system would have been adifficult task if it were not for the National Instruments PID toolkit withauto-tuning. Mink Hollow coded in the software for the two controllersthe ability to enable or disable an auto-tuning mode. At systeminstallation, the application was run in auto-tuning mode, and within afew hours both controllers were stable. Without this time savingfeature, the tuning process would have taken significantly longerowing to the formidably long time constant of the concentration loop.(More than a minute is required for the concentration sensor tomeasure a change resulting from a single drop of pumped chemical,whereas pumping chemical for just 60 seconds oversaturates thechamber.) Once the temperature and concentration controllers weretuned, the parameters were saved to a configuration file that can bemodified if necessary.

User InterfaceProcess Control Panel – Control and data acquisition areconfigured using a laptop computer wirelessly connected to the Compact FieldPoint system. The main front panel allows the user to control the blower, the temperature, and the concentration of the chamber for challenge testing. Concentration is controlling

to 100 mg/m3 with temperature control point set to 140 °F. (Note: in this instance, the thermal set point is out of the achievablerange for the heating elements, yet chemicalvaporisation is occurring and concentrationcontrol is achieved.)

Data Viewer Panel – The “data viewer” is the interface for datalogging configuration. The same interface is used both to log currentdata and to view archived data. Stored in the log file, each channel canbe configured with its own name, units, and scaling. Log files are tabdelimited for easy export to Microsoft Excel for test reports, etc.When viewing or logging, users can add any channel to any plot andtime-synchronise all plots, easily facilitating the simultaneous viewingof a specific time event on multiple plots.

Single Pot Panel – Provides a full-screen plot showing the data of any of the four plots visible in the “Data Viewer” panel.

Convenient, Yet Safe ControlBecause typical tests in the simulant challenge test chamber canroutinely take eight hours, it was imperative for the customer tomonitor the system from different offices within the control building.Wireless connectivity to the control computer achieves this goal,allowing for the monitoring of the system from any number of locationswithout the need for dedicated cables or network infrastructure.

“Hardware requirements and low software development cost led us to select NI Compact FieldPoint hardware and the NI LabVIEWprogramming environment as the system workhorses.”


81Mink Hollow Systems ni.com/aerospace

Wireless connection between the laptop and the control hardwarehas the potential for dropped signals and is a potential problemespecially during critical chamber heating and chemical pumpingperiods. To help safeguard against this potential, we includedLabVIEW Real-Time running on the Compact FieldPoint controller,which checks for a watchdog pulse from the laptop. If a pulse is not received, the connection is assumed to be disrupted and thechamber is put into a safe operating state where the chemical pumpstops and the heating element is turned off.

Because the development of a communications protocol usingTCP/IP would have been time consuming, the National Instrumentstechnology DataSocket (built on TCP/IP) was employed. After theconfiguration of the DataSocket clusters were completed, the laptopand Compact FieldPoint were communicating in minutes saving bothdevelopment and system debug time.

ConclusionMink Hollow selected National Instruments hardware and software as a base platform to provide the Chemical Biological Center at theAPG with a robust custom chamber control system in relatively shorttime within a modest budget, resulting in a successful timely and cost-effective installation. Mink Hollow Systems is looking forward toproviding similar control and monitoring systems in many more legacytest chambers.

For more information, contact: Edward DelaplaineMink Hollow Systems, Inc.6880 Mink Hollow Rd.Highland, MD 20777Tel: (301) 854-1579E-mail: [email protected]


Military/Aerospace Case Studies Politecnico di Torino82

Development of a Dynamic Flight Simulator

Products:NI DAQNI Legacy DAQ Devices

A flight simulator is a system composed by a physically simulatedenvironment, typically the cabin and the cockpit, by a visualisationdevice capable of reproducing a realistic scenery, by some simulatedman-aircraft interfaces (flight command), by a numerical model of theaircraft computing flight dynamics according to pilot’s actions and bya structure that moves the pilot. Such structures are widely used inprofessional pilot training, but their high cost make them unavailablefor non-professional pilots. A professional structure is usually basedon a six d.o.f. Stewart platform actuated by hydraulic servosystemsThe paper proposes a solution that could dramatically reduce thecosts applying a three d.o.f. pneumatically actuated platform formotion, and using mainly components of the shelf to reproduce thecabin and the commands.

Flight simulators are widely used in aeronautics for pilots trainingsince a long time. Usually they are based on large hydraulic Stewartplatforms with six degrees of freedom that allows the reproductionmotion within a very large manoeuvre space. They are completed by a detailed physical model of the environment in which the pilot shalloperate (cabin, cockpit, instruments and flight commands). Thepossibility of using the simulators for officially recognised traininghours is related to the satisfaction of requirements expressed by JARnorms and to the obtainment of certification by the controlling body. Flight simulators are used to train onboard personnel, too. In this case

a platform, again based on the Stewart schematics, moves a cabinreproducing the passengers area of the aircraft or, more commonly, a part of it. The high cost of these simulators, however, limits theirapplications to the training centres of large companies or of militaryaviation. Generally they are not suitable for training of private pilotsbecause their hourly cost is higher than that of the aircrafts typicallyused by flight schools and fllght training organisations.

The project described in this article is oriented to the developmentof a flight simulator characterised by low cost and the possibility ofincreasing the detail of the simulation in an almost modular way inorder to obtain a system that can range from a most economicarrangement used for entertainment only, up to a certified version to be used in pilot training.

The main component of the system is a pneumatic parallel platformwith three degrees of freedom (translation along vertical axis (heave)and rotations about two horizontal axes (pitch and roll)) based on theHPR schematics. The choice of this architecture has been defined inaccordance with the results presented in [3], where the authorscompared two different three d.o.f. parallel architecture (HPR and aspherical mechanism) with a Stewart Platform. They verified that theHPR architecture performed well enough in simulation realism andmight be appropriate for low-cost procedure training simulators.Theplatform was designed by the authors considering 1000 N.

Functional Layout Of The Simulator The pilot sits in a cabin that reproduces as realistically as possible thecabin of the simulated aircraft; in the same way, the main flight

commands, radio commands and the main flightinstruments of the cockpit are reproduced.

The pilot can use the simulated commands to provideinputs to a numerical simulator of the aircraft dynamics(actually Microsoft Flight Simulator) which computes ateach moment a number of flight parameters such asaircraft velocity, acceleration and position, angularcinematic quantities, engine parameters, and so on.

The computed data are used as input for a number offeedback parts which provide the virtual pilot with feelingssimilar to those experienced in a true flight. First, theposition information is directed to a landscape simulationthat places the aircraft in a virtual environment, computesthe view from the cabin and reproduces by mean of asuitable media, usually a screen or a projector. In thesecond line, the main flight parameters such as speed,

G. Mattiazzo, S. Mauro, S. Pastorelli, and M. Sorli –

Politecnico di Torino

THE CHALLENGEDeveloping a dynamic flight simulator characterised by low cost andby the possibility of increasing the detail of the simulation in an almostmodular way in order to obtain a system that can range from a mosteconomic arrangement used for entertainment only, up to a certifiedversion to be used in pilot training.

THE SOLUTIONImplementing the following: n Development of a three d.o.f. pneumatic parallel platform n Microsoft Flight Simulator to compute flying data according to

pilot command and for graphical scene reproduction n I/O management with flexible hardware by National Instruments n Development of motion cueing algorithm to generate motion lows

for the platform according to the aircraft motion n Development of a simulated cockpit n Integration of components into a single structure

MATLAB® and Simulink® are registered trademarks of The MathWorks, Inc.

Figure 1. Logical Organisation of the Flight Simulator


83

height, enginevelocity, and so on,are directed to thevirtual instruments ofthe cockpit. These can be physicalreproductions of theinstruments equippingthe aircraft, or theycan be reproduced ona computer screen.

The feedbackfeelings describedabove are only visualand they are a minimalset of information for

the pilot. The pilot can even be provided with non-visual feedbackfeelings, which can include a force feedback on the flight command,that makes the pilot apply a force similar to that that he should apply intrue flight conditions. Finally, the simulator includes a platform thatmoves the pilot and the cabin, simulating the motion felt on theaircraft. As the platform workspace is necessarily constricted into asmall volume, its motion cannot be equal to that of the aircraft; analgorithm, known as motion cueing, computes trajectories inside theworkspace that induce into the human sensing organs feelings similarto those felt in true flight.

The layout proposed for the simulator described in this article willminimise the total cost of creating a device that can be interesting forentertainment applications. Moreover, the same system, with somemodifications oriented to realise a more realistic cabin environment,could be certified for pilot training to reduce the actual flight hours intraining programs.

Analysing the logic layout of the system, it is possible to distinguishsome software components (aircraft dynamic model, cockpitrepresentation, landscape and scenery); some mechatronics partsinvolving software and hardware as the platform and the flightcommands. Microsoft Flight Simulator is interfaced with a code thatmanages the mechanical parts, i.e. the motion cueing algorithm andthe control of the platform, and the control of the flight commands.

The flight commands include sensors that provide signalsproportional to the command position and actuators that generate the force sensed by the pilot. The software to control all themechanical parts is developed using The MathWorks, Inc. MATLAB®

and Simulink® software.Figure 1 shows the logical organisation of the simulator. It is

possible to distinguish two hardware components (the platform andthe flight commands such as a joystick and the pedals), two networklinked personal computers, one for flight simulation and one for themanagement of the hardware components, and the visual output thatcan be directed to one or more screens. Microsoft Flight Simulatorreceives as input the pilot’s action, opportunely managed by a driver,computes the aircraft trajectory and the forces on the commandsurfaces, and generates the visual output for the scenery and theinstruments in the cockpit. Data about trajectory and forces arepassed to the hardware drivers. Particularly, the trajectory isprocessed by the motion cueing algorithm to compute the platform

motion and forces on the command surfaces are processed by thecommands driver to generate the feedback forces. The second PC(Intel Pentium III, 650 MHz, RAM 256 MB, Windows 98) host eventhe real-time control (XPC TARGET) of the hardware and it is linkedwith sensors and actuators by National Instruments boards (PCI-6052E and Lab-PC-1200).

A PCI-6052E board is connected to six analog input signals –three feedback positions, one from each actuator; and threeposition settings for the platform, (used when the simulator iscontrolled by a joystick instead of MFS); two analog output (twocontrol signals for two control valves, and roll and pitch degrees offreedom), four digital output for safety breaks. The Lab-PC-1200provides one analog output to generate control signal for the thirdactuator (z axes).The high flexibility of the National Instrumentsdevices allowed an easy system integration to obtain all necessaryI/O channels.

Control Schematics The control schematics of the platform is shown in figure 2. The position reference for the platform is a vector including thereference values for pitch (ψ), roll (χ) and height (z). When thesimulator is working, this value is provided by the motion cueingalgorithm. The reference values are processed by the inversekinematic algorithm, that verifies the compatibility with theworkspace and computes the position commands XSETi that mustbe reached by the actuators to realise that particular configuration.The computed values are the reference values for the servoaxes.Each servoaxis is then controlled by a position closed loop. V1, V2

and V3 are the flow-proportional servovalves of axis 1, 2 and 3respectively. Each axis includes even an emergency brake, which is pneumatically actuated by valves VBi. Two adjunctive softwareblocks manage the emergency stop and continuously check thatreferences are inside the workspace. The joint safety algorithmcontrols that the system is not required to reach configurationsclose to singularity points where the forces on the joints couldreach excessive values. The measured passband is about 2.5 Hz in absence of payload, and it decreases to about 1 Hz at full load.This results are compatible with the minimum requirements for the realisation of a motion cueing algorithm for the simulation of acivil aviation aircraft.

ConclusionThe development of a flight simulator with motion can be realisedintegrating a widely diffused simulation software like MicrosoftFlight Simulator with a relatively simply and inexpensive hardware.The proposed structure forecast even the presence of commandsproviding a force feedback to the pilot in order to increase therealism of the simulation. The motion of the virtual pilot is obtainedby a pneumatic parallel platform with three degrees of freedom, and the tests carried out on the platform allows a passband of about 1 Hz at full load. This value allows the reproduction of motionexperienced by the pilot of a commercial aircraft within a large partof the maneuver workspace. In the future, hardware and softwaresystems will be replaced with a PCI-6259 M Series board, and thecontrol system will be developed with LabVIEW Real-Time.

Figure 2. Platform Control Schematics

Politecnico di Torino ni.com/aerospace



Military/Aerospace Case Studies Richmond Measurement Services / NDT Services84

Simulating Aerodynamic Loading onan Aircraft Structure Using NI Products

Products:PXI/CompactPCIMeasurement StudioNI-DAQ

Developing a Test Frame and Constructinga Pressure Control SystemRichmond Measurement Services (RMS) and NDT Services worktogether to solve many test & measurement related problems.Chelton Radomes of Stevenage contracted us to determine a methodof applying representative aerodynamic loads to one of their radardomes, known as a radome, and record the resulting strain applied tothe structure. At RMS and NDT, we developed a test frame andconstructed a novel pressure-control system.

Pressure ControlWe simulated aerodynamic loading by applying pressure into individualpockets placed in contact with the radome surface. We can inflate ordeflate each pocket independently of its neighbours in the pressurerange 0 to 800 mbar. The test specification required us to control thepressure at 5 mbar and measure to 1 mbar. A specially constructedcontrol cabinet houses inlet and exhaust solenoid-operated poppetvalves. We required 40 individual pockets to map the pressure profile.The same enclosure houses pressure sensors so we can accuratelymonitor the line pressure in each compartment.

At RMS, we have many years of experience using NationalInstruments products. We implement NI software and hardware withease to produce robust and reliable systems. Using a PCI-DIO-96parallel 96-bit parallel digital I/O board, we control the inlet and exhaustvalves. We measure manifold and line pressures using a PCI-6071E 64-channel acquisition card. In addition to pressures, we routed thestrain gauge signals into the PCI-6071E.

Providing Reliable Test SoftwareWe wrote the control and acquisition software in Visual Basic using NI-DAQ and Measurement Studio. We used a dual-screen PC systemrunning Windows 2000. At RMS, we use a core acquisition systemthat we developed over many years and add application-specificmodules. The user interface consists of a hierarchy of screens, so wecan view the fundamental inputs for diagnostic purposes, view thederived data for online analysis, and use the test control screensduring the test sequence. Timescales for the test systemdevelopment were short, so we emphasised manual operation andsoftware reliability rather than advanced functions. The entire testsystem performed nearly flawlessly during the test schedule, andChelton Radomes was pleased with the quality of recorded data.The test requirements document defined loading patterns and loadtolerances that should be achieved. The control and recordingsystem that we constructed achieved the required tolerances withfew exceptions. Where tolerance was not achieved, CheltonRadomes was readily able to asses the impact on the results.

The overall conclusion was that the test objectives were met.With this approach to simulation of aerodynamic loads, CheltonRadomes can execute design evaluation in a cost-effective andtimely manner.

For more information, contact: Bernard Killeen, or Joe ManningRichmond Measurement ServicesNDT Serviceswww.RichmondMeasurementServices.co.ukwww.NDTServices.co.uk

Joe Manning and Bernard Killeen –

Richmond Measurement Services / NDT Services

THE CHALLENGEDetermining a method of applying representative aerodynamicloads to a radar dome and recording the resulting strain appliedto the structure.

THE SOLUTIONUsing NI-DAQ and Measurement Studio software to design andconstruct a test frame with a novel pressure-control system.

“Using a PCI-DIO-96 parallel 96-bit parallel digital I/O board, we control the inlet and exhaust valves. We measure manifold and linepressures using a PCI-6071E 64-channel acquisition card. In addition to pressures, we routed the strain gauge signals into the PCI-6071E.”


Developing the Control Center for a NewGreen Rocket Propellant Test Bench at the German Aerospace Research Centre

The Institute of Space Propulsion of the German Aerospace ResearchCentre (DLR) contributes to worldwide research efforts on theutilisation of environmentally friendly, nontoxic propellants for rocketpropulsion applications. Our new green propellant test facility (GPP),currently under construction in Lampoldshausen, is designed toperform engine tests with DLR experimental rocket engines underoperating conditions similar to real service conditions. The GPPprovides combustion chamber pressures up to 6 MPa and hot gastemperatures exceeding 3,000 °C. Our research activities at the GPPuse liquid oxygen as an oxidiser and liquid methane – the most favoredgreen propellant in Europe today – as fuel.

We operate the test bench and route all control and monitoringsignals from a control room at the GPP. To run the rocket tests, anFPGA handles up to 60 digital channels to control different elementsof the test bench, including valves for the fuel inlet among othersignals required for sensor and actuator monitoring. The FPGAprocesses, visualises, and stores the test bench signals during testexecution. PXI FPGA controller devices in the measurement andcontrol center (MCC) supervise and control performance duringoperation, ensuring that all safety procedures are in place andfunctional under all conditions.

In case the nominal control system fails to operate, there are two additional independent subsystems that also perform all safety tasks – the emergencystop system (ESS) and the priority unit (PU).

While the PU monitorswatchdog signals from theMCC, the ESS performs all necessary actions totake the test bench to asafe state in case any ofthe watchdog signals fail.

We also needed astand-alone, real-timesystem that would allowprogrammatic shutdown

of the test bench depending on the current control state, for ESSsafety shutdown in particular. We needed test personnel to be able toprogram this system according to test-specific needs, so the softwarehad to be flexible and open.

The green propellant test facility provides combustion chamberpressures up to 6 MPa and hot gas temperatures exceeding 3,000 °C.

Solution The test bench control and measurement electronics are placed in five19-inch racks with separate, redundant power supplies. The controland supervisory systems are integrated in two of the five racks andconsist of four major parts – three control components and anintelligent switching unit: n The MCC (which was developed by National Instruments

Alliance Partner Werum Software & Systems AG) is based on PXI measurement and control hardware.

n The manual switching panel (MSP) allows manual control of the test bench without any active system in between (such ascomputers or FPGAs).

n The ESS runs on CompactRIO and guarantees direct control of the rocket test bench in any emergency situation, even if the MCC is not working properly or the watchdog fails.

n The PU, which also runs on CompactRIO, selects and decideswhich device is currently in charge of control and routes the control signals between the different systems (manual control, PC control, and the emergency system).

The PU is responsible for safely routing the control signal lines into the systems via a switching matrix built by NI Alliance Partner S.E.A.Datentechnik. The switching matrix shifts control between the threecomponents (the MCC, ESS, and MSP). The PU monitors an externalkey switch and controls the system into the different startup andshutdown modes.

The PU is built into the 19-inch, five-rack unit, which also contains the control signal switching matrix. The unit is based on a CompactRIO system, with an NI cRIO-9101 4-slot chassis with 1 M gate reconfigurable I/O FPGA, an NI cRIO-9002 real-timecontroller, an NI 9425 32-channel digital input module, and an NI 9476 32-channel digital output module. The NI 9425 and NI 9476control the switching matrix and monitor the watchdogs and keyswitches. The matrix routes 3 x 60 inputs to 60 outputs using specialswitching relays to guarantee the required switching time. We can

Products:CompactRIOLabVIEWLabVIEW FPGA

LabVIEW Real-TimePXI/CompactPCI

Wolfram Koerver and Sven Petersen – S.E.A. Datentechnik GmbH

THE CHALLENGERunning a priority unit system and an emergency stop system in agreen propellant fuel-testing facility to monitor signals from a nominaltest bench control system, and performing all the necessary actions to take the test bench to a safe state in case of signal failure.

THE SOLUTIONUsing PXI measurement and control hardware to run a measurementand control center alongside a priority unit, powered by NationalInstruments CompactRIO, to select and decide which device is currently in control of routing the control signals between the different systems; and an emergency stop system, also powered by NI CompactRIO, to guarantee direct control of the rocket testbench in any emergency situation.

85S.E.A. Datentechnik GmbH ni.com/aerospace

The Green Propellant Test FacilityProvides Combustion Chamber Pressuresup to 6 MPa and Hot Gas TemperaturesExceeding 3,000 °C

A National Instruments Alliance Partner is a business entity independent from NI and has no agency, partnership, or joint-venture relationship with NI.


Military/Aerospace Case Studies S.E.A. Datentechnik GmbH86

access and program the CompactRIO system during experimentpreparation and setup phases via a service plate. The procedures andreaction logics to any watchdog failure from external systems areprogrammed into the FPGA unit to ensure the guaranteed reactionwithin milliseconds.

Based on the settings of the key switch or the emergency stopswitch, the FPGA logic sets the output routing to the system in controlat the time to perform the desired action. The test bench can onlyswitch from manual MSP to computer-controlled MCC operation ofthe test bench when certain conditions – indicated by the watchdogsand switch settings – allow a safe change. In case one of thewatchdog signals gets lost or the emergency stop button is pressedduring MCC operation, system control switches to the ESS within aprecisely defined time interval.

The ESS is also based on a CompactRIO system, with a cRIO-91048-slot chassis with 3 M gate FPGA, a cRIO-9004 real-time controller,and NI 9425 and NI 9476 digital I/O modules. The NI 9425 and NI 9476modules handle 180 digital I/O signals. The system is integrated into a19-inch electronic drawer, designed by S.E.A. Datentechnik.

As the backup system for the nominal MCC system, the ESScontinually measures and mirrors the current state of the system’s sixty digital control lines to its sixty digital outputs, allowing the systemto shut down from the test bench’s last reliable state. The shutdownitself depends on the MCC’s current state, which the ESS also monitors. Depending on the MCC’s five digital status lines, the ESS starts one of nine shutdown sequences to bring the test bench into a safe state.The experiment preparation team can easily adapt these sequences to the specific experiment needs. The FPGA software includestemplates for further customer-specific sequence development.

We program the CompactRIO system with LabVIEW FPGA via anEthernet connector behind the service plate. Besides the key switchesand LED indicators, we need no additional operation consoles or PCsto perform the critical safety functions of the PU or the ESS. Weachieve the overall performance, test, qualification, and validation ofthe system with the LabVIEW Real-Time and FPGA modules and withS.E.A. TestMaster using simulation hardware and software to simulatethe environment.

Summary Using National Instruments PXI and CompactRIO real-time technology,we designed a test bench solution to control, monitor, and switchsignals and perform critical safety operations without CPUintervention. By separating different safety-critical functions intoindependent FPGA-controlled systems, researchers and scientistscan achieve fast and simple programming of FPGA functions inchanging operation environments, enabling the preparation and fail-safe performance of critical rocket experiments.

For more information, contact: Wolfram Koerver S.E.A. Datentechnik GmbH51147 Köln, GermanyTel: ++49 22 03 9 80 07 0 E-mail: [email protected]


Developing a Monitoring and Control System forStructural Aircraft Tests Using LabVIEW and PXILuca Cambiaso – SITEM s.r.l.

THE CHALLENGEBuilding an easy-to-use program for a rugged control system thatcan handle structural and fatigue tests on fuselage or other partssuch as the wing or rudder.

THE SOLUTIONCreating a data acquisition and control system based on real-timetechnology using PXI and LabVIEW Real-Time platform.

87

Products:LabVIEWLabVIEW Real-TimePXI

A Multifunction SystemWe developed an application for Piaggio Aero Industries Spa, a leader in designing and building executive aircrafts, for the purpose of monitoring and testing these types of aircrafts.

We divide the software program into two components. One is on a PXI system interfaced towards instrumentation on field testassembly, and the other component is on a standard PC that acts as asupervision unit. We used an Ethernet link to connect the PC and PXI.The program can handle up to:n 128 analog input channelsn 24 analog output channelsn 112 digital input channelsn 40 digital output channelsn 2,000 GPIB channels from instrumentation

Additionally, the program can work with two different kinds of tests:n A static test or “manual mode”n A fatigue test or “automatic mode”, which is a dynamic test.

Moreover, we developed a third kind of operating mode. This mode helps the operator check the whole system at start-up or inspecific situations.

In fact, using this mode, the user can activate every actuatorindependently from any logic control loop, verifying test assemblybehavior at a specific point and/or verifying the correct functionality for every part of the system, such as pressurizing the cabin of the airplane.

Hardware ArchitectureWith National Instruments LabVIEW Real-Time and PXI System, we can efficiently develop new test consoles within weeks, asopposed to months.

The system is composed of a desktop PC (NT 4.0 Workstation OS)connected via Ethernet to the data acquisition and control systembased on a real-time PXI. The PXI then connects to third-party dataacquisition component via GPIB.

The PXI system is composed of a PXI-1000 chassis with a real-timePXI-8156B controller, two general-purpose PXI-6071 DAQ boards,three data generation PXI-6713 boards, and, lastly, two PXI-6508 digitalboards. Signal connections among the PXI system, the servo controlsystem (analog CYBER PID units), and oleo-pneumatic actuators aremade using DIN rail-mounted terminal blocks.

Software ArchitectureThe software program is composed of two different components. The first is a data acquisition and control component that runs on the PXI control unit processor. This component exchanges data andcommands with the second one that is a supervision and userinterface component running on the PC.

Improved Data ExchangeTo improve data exchange between the control unit and thesupervisory unit, we used VI reference technology, developing adedicated VI library. Moreover, to prevent system and operatingdamages, we added a watchdog mechanism – alarms sound if anycommunication breakdown occurs.

From the beginning, using the supervision component we can load or edit an .ini configuration file that describes the test. Ini files can be more than 20,000 rows long, and are fundamental to the dataacquisition process from boards and from GPIB instrumentation.Moreover, they are fundamental in generating stimulus signals for actuators.

Two other kinds of files define the loads matrix used in dynamicfatigue tests and the correlations matrix. These files describe analoginput and output, digital input and output, and channels read fromGPIB instrumentation. The loads matrix defines all possible load values.

For each of the 24 analog outputs corresponding to 24 actuators,the correlations matrix describes electric and mechanical relationshipsbetween analog output channels, exciting jacks servo controls, andacquisition channels with feedback signals. After loading the correctconfiguration file, the operator can launch static tests or fatigue testsor can check the system.

Static Test ManagementAn operator must work onsite during static test sequences. Anoperator must first run two important procedures such as applyingsystem calibration and removing zeros before applying loads. Theseprocedures bring the system to an optimal initial situation. Then theoperator manually moves the system step by step from a predefinedload percentage to another one, applying a straight path.

We can do this both from the program GUI through an ad hoccontrol slider and using a variable resistance potentiometer acquiredwith an analog input channel. The potentiometer is a very usefuldevice because the operators can continuously and slowly change the load percentage. We developed special routine to avoid theeffects of abrupt movements on the potentiometer.

Load percentage values, read from feedback servo controls signals,are shown on video also with values from analog input GPIB channels.We developed an important tracking routine so that during systemloads, parameters change from one value to another and the softwarerecognises tracking alarms generated from servo controls. These

SITEM s.r.l. ni.com/aerospace


alarms generate when servo controls do not reach the desired loadvalues. So, when a tracking alarm occurs, the software reacts byrunning the tracking routine that raises or lowers stimulus andfrequency generation until the alarms stops.

The data generation function, which can manage up to 24 analogoutput channels, reads tension values from configuration files, directlywrites them on DAC FIFO, and generates them at the demandedfrequency. Generation frequency is the same for all DACs and maychange if tracking alarms conditions occur or not. Tracking alarms areshown in an appropriate window.

The test automatically stops if a major alarm occurs, called a faultalarm. Both the fault alarm and tracking alarms are digital inputs anddefined by software (active/tracking/fault etc.) using .ini files and GUI.

Fatigue Test ManagementFatigue test sequences can run without operator supervision.

After loading the configuration file, applying system calibration, and removing zeros, as in static tests, the system can program DACconverters with an opposite function, in order to obtain the excitationcurves that perform flight simulation.

Excitation curves are obtained with sinusoidal interpolationbetween prefixed points. The program can join together two pointswith sine wave branch interpolations of 100 points. The shift betweenone point to the next takes three seconds if no alarms occur. Also, inthis kind of test, the follow routine is used to handle tracking alarmsfrom servo controls.

Load parameters are stored on ASCII files describing point afterpoint final load conditions, which are interpolated using 100 points.Using specific commands in the same file, we can perform severaloperations such as a “pause” in the test, “perform complete dataAcq,” update the number of “simulated flights or flying hours”, open and close the pressurisation valve, automatically load anothertest file, and more.

On video parameters, monitors show test status such asgeneration frequency, number of simulation flights done, andpercentage of test done. The test automatically interrupts if any fault alarms occur. To conclude, the supervision program generates a log file to trace events.

For more information, contact: SITEM s.r.l.Via Merano 7/116154 GenovaTel: +39 010 6591757Fax: +39 010 6593722E-Mail: [email protected]

Military/Aerospace Case Studies SITEM s.r.l.88

“With National Instruments LabVIEW Real-Time and PXI System, we can efficiently develop new test consoles within weeks – as opposed to months.”


Using CompactRIO to Develop a RotocraftUnmanned Air VehicleRoberto Pretolani, B. Teodorani , and G.M. Saggiani –

University of Bologna School of Engineering

THE CHALLENGEDeveloping a helicopter platform capable of autonomous flight to be used for control and navigation research in a university setting.

THE SOLUTIONProgramming a complete control system using National InstrumentsLabVIEW and CompactRIO as the flight computer to manage flightdata acquisition and control the helicopter.

89University of Bologna School of Engineering ni.com/aerospace

At the University of Bologna (UNIBO) DIEM Aerospace Department,we have developed a rotocraft unmanned air vehicle (UAV) for use as a test bed for researching UAV control and navigation.

The increasing interest in military UAVs is fueling an ambitiousbuild-up in the private sector. It is well-known that UAVs represent apromising and cost-effective alternative to manned aircraft for manycivilian applications. Compared to traditional air vehicles, UAVs offersignificant advantages in terms of human safety (especially in dull,dirty, and dangerous missions), operational cost reduction, and workrate efficiency.

UAV and rotary wing UAV (RWUAV) system research is veryadvanced in the United States, but interest in Europe has begun onlyin recent years. As a result, the European Union has sponsoredCAPECON, a UAV development program designed to kick-start acivilian UAV industry in Europe. At UNIBO, having recently carried outseveral research projects focused on developing and manufacturingfixed-wing UAV systems for the civil aviation market, we were eagerto participate in the CAPECON program.

In addition, UNIBO has started a RWUAV research program,recognizing RWUAV systems as an alternative to fixed-wing UAVs for many civil applications due to their versatile flight modes,maneuverability, and vertical take-off and landing capability. The maingoal of our RWUAV research program is to develop a helicopter capableof autonomous flight to be used for control and navigational research.

Hardware and System ArchitectureWe have built two model helicopter platforms, each with 5.5 kgpayload capacity. Autonomous flying vehicles require avionics systemsthat let them maintain a stable altitude and follow desired trajectories.Such an avionics package consists of sensors, a computer, and data-link hardware as well as software to guide, navigate, and control thevehicle. These components are particularly critical for helicopters,which are well-known to be inherently unstable systems. For thisreason, we decided to use National Instruments CompactRIO.

We have modified the Hirobo 60 and Graupner 90 hobby helicoptersto accommodate the avionics hardware. NI CompactRIO works as theflight computer, and CompactRIO FPGA modules acquire sensorinformation and generate PWM actuator signals based on the controlalgorithms. CompactRIO Real-Time controllers receive sensorinformation from the FPGA and record all flight data, also managingwireless Ethernet communications with the ground control station. The CompactRIO FPGA receives and sends PWM actuators signalsthrough the NI cRIO-9411 digital input module and the NI cRIO-9474digital output module, respectively. The system acquires status

parameters such as battery voltage by means of the NI cRIO-9201analog input module.

The entire system weighs about 5 kg – well within the payloadcapability of the small-scale helicopters available to us. If biggerhelicopter platforms become available, one or more NI CompactRIOmodules could also act as backup and safety systems for the UAV.

SoftwareThe RWUAV system has the typical CompactRIO application designarchitecture. The FPGA code uses four different timed read/writeloops and one PID control loop for helicopter altitude control. The PIDloop is closed at 50 Hz, and the write loops send PWM commands tothe helicopter servo actuators and to the stabilised camera mountactuators. The first read loop acquires helicopter altitudes, angularrates, velocities, and GPS position from the Crossbow NAV420,which uses the RS232 protocol. The RS232 protocol is managedusing FPGA digital input to guarantee deterministic data acquisition,which could not be achieved using a real-time application.

We use National Instruments LabVIEW Real-Time software forFPGA data acquisition, embedded flight data logging, and wirelessEthernet communication with the ground control station, managingground control station communication with the NI LabVIEW Real-TimeCommunication Wizard. We developed the ground control stationsoftware in LabVIEW for Windows, and we run it on a laptopcomputer using Windows XP. The remote graphical user interfaceconsists of two windows – the vertical cockpit window and thetelemetry window – for real-time display of flight data information.

Conclusion and OutlookWith the help of National Instruments hardware and software, UNIBOlaboratories is successfully developing a RWUAV as an integrated,reconfigurable system for researching control and navigation laws inrotary wing and fixed-wing UAV concept development. We performedthe first flight campaign to test onboard sensor data acquisition andPID altitude control systems in hovering conditions. CompactRIOproved to be an easy-to-use, programmable tool that was reliableenough for helicopter control. In the near future, we plan to implementadditional sensors (such as sonar altimeters) into the avionics package,to perform flight testing for more advanced maneuvers, and toimplement navigation algorithms to build up a fully autonomous rotary wing system.

For more information, contact: Roberto Pretolani, Department of Aerospace Engineering University of Bologna School of EngineeringTel: 39-0543-786932Fax: 39-0543-786940E-mail: [email protected]

Products:LabVIEWCompactRIO

LabVIEW Real-Time Communication Wizard


Military/Aerospace Case Studies University of Bologna II School of Engineering Forli90

R. Pretolani, G. M. Saggiani, B. Teodorani, and F. Zanetti –

University of Bologna II School of Engineering Forli

THE CHALLENGEDeveloping an HIL test bench for the rotary wing UAV (RUAV)platform available at the University of Bologna. The HIL must becapable to emulate the real UAV system in order to allow safe and risk-free pre-flight testing.

THE SOLUTIONDeveloping the HIL simulator as an integrated modular system using National Instruments hardware and software. The RUAVsystems were emulated using the NI PXI-7831 (instead of the onboardCompactRIO controller and FPGA modules), while the RUAV platform was simulated by implementing a helicopter model using the NI LabVIEW Control and Design Simulation Module software.Comparison with flight tests demonstrated that the developed HILsimulator is a reliable test bench for safe ground tests of the onboardRUAV control system.

Development of a Hardware-in-the-Loop (HIL)Simulator for a Rotary Wing UAV

At the University of Bologna – DIEM Aerospace Department, arotorcraft UAV was developed using the NI CompactRIO system asonboard computer for flight data acquisition and helicopter control.During the first flight tests the UAV helicopter was able to perform acomplete flight pattern under computer control. Parallel to the RUAVplatform, a modular HIL test bench was also developed in the NI LabVIEW environment to allow safe and risk-free pre-flight hardwareand software tests. The developed HIL test bench (see Figure 2)includes as much of the flight hardware in the testing loop as possibleand is constituted by both software and hardware equivalent to theonboard systems. Particularly, the National Instruments PXI-7831 wasused instead of the CompactRIO FPGA modules. Inside the HIL, theRUAV platform was emulated by implementing a helicopter simulationmodel using the LabVIEW Control and Design Simulation Modulesoftware. Comparison with flight tests demonstrated that the HILsimulator can be a reliable test bench for safe ground tests of theonboard RUAV control system.

Background It is well known that UAVs may represent a promising and cost-effective alternative to manned aircraft for a large number of civilapplications. Compared to traditional air vehicles, UAVs may offersignificant advantages in terms of human safety (especially in dull,dirty and dangerous missions), operational cost reduction and workrate efficiency. In the last years, UNIBO has carried out severalresearch projects concerning the development of UAVs platforms,both fixed and rotary wing, for civilian applications. In order to developsuch kind of platform, new avionic systems are required that enablethe helicopter to maintain a stable attitude and follow desiredtrajectories. This avionics package is comprised of sensors, computerand data link hardware as well as software to guide, navigate andcontrol the air vehicle. Generally speaking, the setup of an avionicpackage for RUAVs requires a number of skills which span the area of micro-circuitry, data link communication, electronics integration,installation and programming, filter design, signal conditioning andvibrations isolation. Most of the existing RUAV projects use onboard

electronic devices, which require the employment of numerous experttechnicians for system assembling and testing, thus increasing thedevelopment time and total costs.

At the University of Bologna, the RUAV avionics package wasdeveloped as an integrated modular system using off the shelf andcost effective technologies. The CompactRIO system from NationalInstruments was chosen as flight computer due to its reliability andreconfigurable architecture, which enables fast and easy integration of different input/output hardware and sensors.

Parallel to the helicopter platform construction and avionics setup, a modular hardware-in-the-loop (HIL) test bench was developed in theNI LabVIEW environment, to allow safe and risk-free pre-flight testing.The CompactRIO system and the HIL simulator were fast and easilyprogrammable, resulting in a sudden speed-up of hardware/softwaredevelopment and integration. These systems will be described in the following sections.

Hardware And System Architecture Usually, the set up of a RUAV system requires a series ofsubsequent steps to be undertaken, including: n Hardware selection and system setup n Design of sensor acquisition software and control system n Development of an HIL simulator test bench to allow risk-free

ground test of the flying hardware and software n Final autonomous flight experimental tests

Products:CompactRIOLabVIEWLabVIEW Real-TimeLabVIEW FPGA

LabVIEW Control and Design Simulation Module

Reconfigurable I/O

Figure 1. System Architecture


91University of Bologna II School of Engineering Forli ni.com/aerospace

The RUAV system architecture and the HIL simulator are shown inFigures 1 and 2. Both the flying systems and the HIL simulator weredeveloped through extensive use of National Instruments hardwareand software. The RUAV platform developed at UNIBO is constitutedby a Hirobo 60 hobby helicopter which was modified to accommodatethe avionics hardware. A more powerful engine, longer fiber glassblades, longer tail boom and tail blades were also mounted in orderto increase the helicopter payload carrying capabilities.

The NI CompactRIO was used as a flight computer in order toacquire sensors information and generate PWM actuator signalsbased on the control algorithms implemented on it, particularly: n CompactRIO FPGA receives flight data information from the

Crossbow NAV420 AHRS (attitude heading reference system) managing an RS232 protocol through the digital input cRIO-9411

n CompactRIO FPGA receives and sends PWM actuators signalsthrough digital input cRIO-9411, and output cRIO-9474, respectively

n CompactRIO acquires sonar sensor altitude information by managing an I2C protocol using the digital input cRIO-9411 and output cRIO-9474

n CompactRIO real-time core receives sensor information from theFPGA and records all the flight data; meanwhile it manages alsowireless ethernet communication with the ground control station

The developed HIL test bench includes as much of the flighthardware in the testing loop as possible and consists of: n Hardware equivalent to the flight computer which runs the

onboard software. At this aim, an NI PXI-7831R was used as it isequivalent to the CompactRIO FPGA modules. PXI communicationwith the computer (emulating the CompactRIO real-time core) can be performed by means of an FPGA interface card.

n A computer which emulates the helicopter plant and the onboardsensor outputs. A ground control station (GCS) computer which contains the real GCS source code and communicates with thesimulation computer by means of the TCP/IP protocol.

n An OpenGL visual system computer can be optionally added forrendering the helicopter flight as it moves around in a virtualscenery. The visual system can receive input from the GCS computer using a TCP/IP protocol

SoftwareFigure 3 shows the LabVIEW code which manages the whole RUAV system, while Figure 4 shows the equivalent code in the HILsimulator. Both software programs have the typical CompactRIOapplication design architecture.

Particularly, for the real RUAV system: n The FPGA code uses four different sensor read/write loops and

one PID control loop for helicopter control. By now the PID loop is closed at 50 Hz. The write loops send PWM commands to thehelicopter servo actuators (main rotor cyclics and collective, tailrotor collective and engine) in order to track a pre-defined flightpattern. The first read loop acquires helicopter attitudes, angularrates, velocities and GPS position from the Crossbow NAV 420which uses a RS232 protocol; the RS232 protocol has been managed using the FPGA digital input to guarantee deterministicdata acquisition, which couldn’t be achieved using a real-time application. The second read loop manages PWM command data acquisition. Another read/write loop is used for sonar sensor data acquisition and manages an I2C protocol.

n CompactRIO real-time software is used for FPGA data acquisition,onboard flight datalogging, and wireless Ethernet communicationwith the ground control station, all managed by means of theLabVIEW Real-Time communication wizard.

n Ground control station software is also developed in LabVIEW forWindows and runs on a laptop computer using Windows XP (Hostcomputer). The remote graphical user interface consists of twowindows – the virtual cockpit and telemetry window – for real-timedisplay of flight data information (see Figure 3).

n The first one has been developed using also ActiveX controls,such as aircraft instrumentation available from Global MajicSoftware House. Additional information is available such as GPSand inertial measurement unit status and system warnings. Figure 2. HIL Simulator Architecture

Figure 3. RUAV Software


Military/Aerospace Case Studies University of Bologna II School of Engineering Forli92

The equivalent code in the HIL simulator is constituted by the sameFPGA code of the real RUAV system running on the NI PXI-7831R; the software running on the simulation computer is composed ofthree main parts: n The simulation loop, which contains the helicopter simulation

model, developed using the LabVIEW Control and DesignSimulation Module

n A serial port write-loop for emulating the Crossbow NAV 420RS232 output, based on the states information coming from the helicopter simulation loop

n The same CompactRIO real-time software. For practicality reasons, the helicopter simulator and the real-time code run on the same machine. This is possible because all the source code is organised using independent loops; the software running on the GCS computer which is the same as the real GCS software

The result of this setup is that the onboard computer effectively“thinks” it is flying the vehicle, as all of its configuration/data flow isidentical to an autonomous flight setup. In this scenario, performanceand possible errors of the onboard software can be detected duringintensive ground safe simulations, before performing any flight test.

Results and Conclusion HIL simulations and experimental flights were performed in order totest the feasibility to use the selected hardware and the developedsoftware for helicopter control. Comparison between simulation andexperimental results showed good agreement (see Figure 5), thusdemonstrating the feasibility to use the developed HIL simulator asground safe test bed for the UNIBO RUAV system.

In the future, the simulation platform will be further improved. More sophisticated dynamics models will be implemented on the HIL simulator, including more accurate models of all flight sensors.

Coupled with the RUAV platform, these simulation environmentswill provide useful test beds for safe ground pre-flight tests or forstudying different control and navigation strategy. Researches in manmachine interface and air system integration could also be performed,which were addressed as one of the most critical technology aspectfor the future development of the civil UAVs and their integrationinto the airspace.

Figure 5. Comparison Between Flight Tests and HIL Simulations

Figure 4. HIL Software Implementation


©2008 National Instruments Corporation. All rights reserved. LabVIEW, National Instruments, NI, ni.com, and NI TestStand are trademarks of National Instruments. Other product and company names listed are trademarks or trade names of their respective companies.

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Advanced parallel testing andmulticore development tools

Industry’s lowest latency andhighest throughput test platform

Optimised drivers and controllersfor more than 5,000 instruments

PRODUCT PLATFORM

NI TestStand software

NI LabVIEW graphical software

PXI modular instrumentation

High-Level Programming Environments

NI LabVIEWNational Instruments LabVIEW utilises multicoreprocessors and new bus technologies to create high-performance test systems capable of parallelprocessing, parallel measurements or parallel test on the production floor.

ni.com/labview

LabWindows™/CVINational Instruments LabWindows/CVI is a proven ANSI Cintegrated development environment that provides acomprehensive set of programming tools for instrument control,data acquisition, analysis and user interface development.

ni.com/lwcvi

NI TestStandNI TestStand is a ready-to-run test management environmentdesigned to accelerate the development, management and execution of test sequences written in any test programming language.

ni.com/teststand

PXI Chassis, Controllers and RAID Storage

PXI is an open, multivendor standard with more than 1,200modules from 70 vendors in a small, rugged platform delivering 10 times the performance of older architectures. PXI Expressincorporates the latest PC bus technology for streaming terabytesof data between modules and high-capacity RAID storage drives.

ni.com/pxi

NI Modular Instruments

NI modular instruments offer compact, high-performancemeasurement hardware with integrated timing and triggering.Synchronise multiple instruments for mixed signal applications,or add additional modules for future system requirements.

ni.com/modularinstruments

Oscilloscopes (High-Speed Digitisers)High-speed digitisers and oscilloscopes with sampling rates up to 2 GS/s, bandwidth to 300 MHz, 8 to 24-bit resolution and up to 8 channels in USB, PCI, PXI and PXI Express.

ni.com/digitizers

Signal GeneratorsFunction and arbitrary waveform generators with 12- and 16-bit resolution at up to 400 MS/s sample rates for PCI, PXI and PXI Express.

ni.com/signalgenerators

High-Speed Digital I/O and Logic AnalysersDigital waveform generators/analysers featuring maximum clockrates up to 200 MHz, data rates as high as 400 Mb/s, and flexiblesingle-ended and differential voltage levels for PCI, PCI Express,PXI, PXI Express and PCMCIA.

ni.com/hsdio

RF and High-Frequency DevicesVector-based signal acquisition, generation and analysis up to 6.6 GHz with 20 MHz real-time bandwidth.

ni.com/rf

Digital Multimeters (DMMs and LCR Meters)Includes 51⁄2 -, 61⁄2- and 71⁄2-digit DMMs with 10- to 26-bit resolution andup to 1.8 MS/s sample rates for USB, PCI, PCI Express and PXI.

ni.com/dmm

Programmable Power Suppliesand Source Measure Units (SMUs)Programmable DC power supplies with 16-bit programming and readback, and SMUs with 4-quadrant outputs offering down to 1 nA measurement resolution.

ni.com/smu

Dynamic Signal Acquisition, Generation and Analysis24-bit precision for sound and vibration acquisition and generation.

ni.com/soundandvibration

SwitchesHigh-quality switching solutions including general-purposerelays, multiplexers and matrices for PXI and SCXI.

ni.com/switches

National Instruments UK and IrelandMeasurement House, Newbury Business ParkLondon Road, Newbury, Berkshire, RG14 2PSUK 01635 523545 n Ireland 01 867 [email protected] n [email protected] n ni.com/uk n ni.com/ireland

© 2008 National Instruments Corporation. All rights reserved. CompactRIO, CVI, DAQPad, DataSocket, DIAdem, FieldPoint, FlexMotion, LabVIEW, Measurement Studio, MXI,National Instruments, National Instruments Alliance Partner, NI, ni.com, NI CompactDAQ, NI TestStand, RTSI, and SCXI are trademarks of National Instruments. The markLabWindows is used under a license from Microsoft Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and other countries. Otherproduct and company names listed are trademarks or trade names of their respective companies. A National Instruments Alliance Partner is a business entity independent fromNI and has no agency, partnership, or joint-venture relationship with NI.


2008-9322-503-111-I

National Instruments Corporation (UK) Ltd n Measurement House n Newbury Business Park n Newbury n RG14 2PSRegistered Office: 42-46 High Street Esher n Surrey n KT10 9QY n United Kingdom: Company Registration No. 2999356 n VAT No. GB493598779

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