Computerized Measurement Systems (EEMN10)...
Transcript of Computerized Measurement Systems (EEMN10)...
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Computerized MeasurementSystems (EEMN10) 2014CHRISTIAN ANTFOLK & JOSEFIN STARKHAMMAR
Course information 2014• Course administrators:
Christian Antfolk ([email protected])
Josefin Starkhammar ([email protected])
• Course webpage :
http://bme.lth.se/course-pages/datorbaserade-maetsystem/
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Course information 2014
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Course information 2014
• Goal: to give an overview of systems and methods to collect measurement data with the help of a computer in test and industrial environments. To program such a system in eg.LabVIEW or Matlab in a logical and structured way in order to solve a measurement task.
• Lectures: Lectures in this room (E:1328), Tuesdays & Fridays
• Course litterature: Will be made available on the coursewebpage
• Grades: Passed assignments (handed in on time!), laboratory exercises and project = grade 3. Higher grades require taking the exam.
• If you decide NOT to follow the course please let us know
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Course information 2014
• 3 Assignments
– Assgn 1: LabVIEW (Hand-in deadline Monday 17.11.2014)
– Assgn 2: DAQ Boards (Hand-in deadline Monday 24.11.2014)
– Assgn 3: Home Lab (Hand-in deadline Monday 16.12.2014)
• 2 Labs
– Lab 1: GPIB (Academic week 3, room E:1309b)
» Wednesday 19.11.2014 8-12 or 13-17 or Thursday 20.11.2014 8-12
– Lab 2: DAQ-PAD (Academic week 4, room E:1309b)
» Wednesday 26.11.2014 8-12 or 13-17 or Thursday 27.11.2014 8-12
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Course information 2014
• Project:
– Build a measurement system (room E:1309B)
– Choose project week 4 of the course
– Short project description and suggested approach tosolution Monday 01.12.2014
– Short oral presentation Friday 19.12.2014 + writtenreport
– Report hand-in Friday 19.12.2014
• Gear : PC with LabVIEW and Matlab
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Example projects
• FPGA/CompactRIO-based measurements (industry)
• Automated Voltage vs. Frequency measurement for an acoustophoresis setup (BME)
• Control of pneumatic actuators for stimulation in an fMRI environment. (Radiation Physics / BME)
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Schedule (subject to change)
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Academicweek Day Date Time Place
Lect no: Topic Lecturer Assignments
Labs (E:1309b) Project
1Tuesday 04.11.2014 13‐15 E:1328 1 Introduction to the course CA
Friday 07.11.2014 13‐15 E:1328 2 LabVIEW I (introduction, variables, structures etc) JS
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Tuesday 11.11.2014 13‐15 E:1328 3 LabVIEW II (subVI's, error wires, data flow control) :: Assgn 1 info JSAssgn 1: LabVIEW assignment (Deadline Monday
17.11.2014)Friday 14.11.2014 13‐15 E:1328 4
Databuses and communications
CA
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Tuesday 18.11.2014 13‐15 E:1328 5 Instrument control :: Lab1 and Assgn 2 info & prep JSAssgn 2: DAQ
board assignment (Deadline 24.11.2014)
Lab1 : GPIB
Friday 21.11.2014 13‐15 E:1328
NO LECTUREChoose project
4 Tuesday 25.11.2014 13‐15 E:1328 6
Data acquisition boards and USB‐DAQ :: Lab 2 and Assgn 3 info & prep
JSLab2:
DAQ‐PAD
Project plan (deadline
01.12.2014)
Friday 28.11.2014 13‐15 E:1328 7 Data acquisition using Matlab :: Assgn 3 info & prep JS
Project execution
5Tuesday 02.12.2014 13‐15 E:1328 8 Signal conditioning CA
Assgn 3: Home Lab assignment (Deadline
16.12.2014)
Friday 05.12.2014 13‐15 ???? 9 LabVIEW in industry / Design patterns GUEST
6Tuesday 09.12.2014 13‐15 E:1328 10
Signal processing data presentation, questions and check‐upCA/GUEST
Friday 12.12.2014 13‐15 E:1328 11Software for measurement systems (LabCVI, Measurement Studio, HP‐VEE, Dasylab)
CA/GUEST
7Tuesday 16.12.2014 13‐15 E:1328 12 Project presensation / demonstrations CA
Friday 19.12.2014 13‐15 E:1328 NO LECTURE
8Wednesday 14.01.2015 8‐12 E:1328
EXAMINATIONReporthand‐in
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Overview of the course content
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Computerized measurement system example
Physical quantity Measurement system
Signal processing
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Sensor
Physicalquantity, eg. soundwave
Signal conditioning, eg. filters & amplifiers
Instrument withdata bus
interface, eg. USB or PXI
Personal computer
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Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical programming• LabVIEW
• Agilent VEE
• DASYlab
• Textual programming• LabWindows CVI
• Measurement Studio
• Visual Basic
• Visual C/C++
• Matlab
Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical programming• LabVIEW
• Agilent VEE
• DASYlab
• Textual programming• LabWindows CVI
• Measurement Studio
• Visual Basic
• Visual C/C++
• Matlab
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Signal conditioning
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• How does the sensor/transducer work?• Change in resistance (strain gauge, Pt100) -> Wheatstone bridge
• Voltage (thermocouple, piezo transducer)
• Current (semi-conductors) -> generate known voltage drop over known R
• Filterering (50 Hz), isolation (opto), amplification?
• A/D conversion• Adapt the signal to the working range of the A/D converter
• Dynamic range (Difference between the smallest and biggestmeasurable values)
• How many bits (resolution) does the measurement system has tohave to meet the need for measurement accuracy? (8 bits = 2^8=256 signal levels across the measurement range)
(+ 10 V => 78 mV per level. 16 bit => 0.3 mV per level)
Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical programming• LabVIEW
• Agilent VEE
• DASYlab
• Textual programming• LabWindows CVI
• Measurement Studio
• Visual Basic
• Visual C/C++
• Matlab
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Example of a DAQ card
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• Programmable range
• 2 x 12-bit Analog Outputs
• Internal or external trigger
• 16 Analog inputs• 12-bit A/D converter• 1 multiplexed A/D converter• 110 kHz sampling frequency
Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical programming• LabVIEW
• Agilent VEE
• DASYlab
• Textual programming• LabWindows CVI
• Measurement Studio
• Visual Basic
• Visual C/C++
• Matlab
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General Purpose Interface Bus
• Introduced by HP 1965
• 1 MB/s
• Requires special cables and och plug-in cards
• Max 20 m total cable length and 15 instruments
• Still very much used for instrument control in both industry and research environments, probably due to the rugged connectors
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
General Purpose Interface Bus
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical programming• LabVIEW
• Agilent VEE
• DASYlab
• Textual programming• LabWindows CVI
• Measurement Studio
• Visual Basic
• Visual C/C++
• Matlab
Serial communications
• RS-232
– Unbalanced (one ground wire + one active wire)
– Point-to-point
– Up to 19,2 kbit/s at 15 m cable
• RS-422
– Balanced (both wires are active but in opposite phase)
– Point-to-point
– Up to 2 Mbit/s
• RS-485
– Balanced (both wires are active but in opposite phase)
– Multiple units are connected in parallel, however the communication is serial (Multidrop)
– Up to 10 Mbit/s
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Comparison RS232 – RS422
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Tx
GNDRS232
Tx-
Tx+
RS422/RS485
0
1
Serial communication
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• USB, FireWire, Ethernet
– 5 m cable for USB,
– 5 Gbit/s (USB 3),
• FireWire
– 72 m cable
– 3.2 Gbit/s
• Ethernet
– 72 m cable
– 10 Gbit/s
• SATA 3
– 8 m cable
– Up to 6 Gbit/s
– Designed to send data quickly to harddrives
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Example of USB based system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalquantity
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical• LabVIEW
• LabCVI
• Measurement Studio
• Agilent VEE
• (DASYlab)
• Command• LabWindows
• Visual Basic
• Visual C/C++
• Matlab
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What is a computer bus?
• A collection of wires which transfer digital data according to a specific protocol between separate units.
• There are several standards to allow seamless connectivity of instruments from a number of different vendors.
– Example : PCI, USB, GPIB, Firewire, SATA, Ethernet, etc
• Example of entire systems with specific computer buses incorporated in each unit are fieldbuses, VXI-systems, PXI-systems, real-time controllers etc.
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
The PCI bus in a PC
• The PCI-bus, 32 bits, 133 MB/s, 33 MHz
• ”Peripheral Component Interconnect”
• The PCI-e bus, ”PCI-express”, 64 bits, 256 MB/s per line (total of 20 lines), 2 GHZ
• Full duplex = to send and receive data at the same time => 512 MB/s
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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VXI – VMEbus eXtensions for Instrumentation
• Faster and more compact than GPIB (40 MB/s with a 32 bit bus)
• Produced by 250 vendors
• Can be connected through MXI (Multisystem eXtensionInterface), or GPIB if there are other more traditional instruments in the system
• FireWire (IEEE-1394), USB, LAN etc…
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
PXI – PCI eXtensions for Instrumentation
• Like VXI but with PCI bus
• More compact, ”cheaper”
• Also PXIe for the faster PCI express bus
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Real time controllers
• Basic idea: combine measurement tasks and signal generation with dedicated hardware
• Advantages: fast, robust
• Car industry, power industry, automation
• Plug in cards
• Stand alone module
• Industrial systems
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Fieldbuses
• Used to interconnect automation devices in a network
• Heavily used in industry
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Fieldbuses
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Fieldbuses - example
• Cars (CAN-bus)• More and more gadgets and driver aid systems has
increased the total weight of the wiring in cars. (Engine control systems, ACC, ABS, ESP...)
• Gambro’s AK100
• Elevators
• Photo copy machines
• Toys
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Why use fieldbuses
• Distributed intelligence gives:
• Less cabling, especially over long distances
• Measurement cells can be made self calibrating or be calibrated remotely through the bus
• Self diagnostic systems
• Flexible system when transducer units are exchanged
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Structure of a measurement system
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
• pressure
• temperature
• speed
• angular velocity
• luminosity
• force
Physicalentety
Measurementsystem
Presentation(and control)
• Signal conditioning
• DAQ-cards
• Bus control of instruments• GPIB (parallel)
• RS232 (serial)
• Bus systems with integrated and standardized instruments• VXI/PXI
• Real time controllers
• Field buses
• Graphical• LabVIEW
• LabCVI
• Measurement Studio
• Agilent VEE
• DASYlab
• Command• LabWindows
• Visual Basic
• Visual C/C++
• Matlab
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LabVIEW
• National Instruments
• Graphical Programming Language
• ”G”
• Current version LabView 2014
• Virtual Instruments
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Virtual instruments
• Three mail building blocks:
• Data collection (software for communication with measurement device, e. g. ordinary instrument, DAQ-card or through VXI/PXI)
• Analysis (statistics, filtering, spectral analysis...)
• Presenation (all settings can be handled through the program window which is designed for the specific measurement task, data presentation etc. Hence, the name Virtual Instrument)
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Example of a LabVIEW program• Front panel
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
Example of a LabVIEW program• Block diagram
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
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Dataflow programming
• Execution determined by the structure of the program
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering
A poor example of a LabVIEW program
Lund University | Faculty of Engineering | Dept. of Biomedical Engineering