How to use LabVIEW -...

How to use LabVIEW

Ihor Korolov

February 2011

Contents

  What is LabVIEW?

  How does LabVIEW work?

Block diagram Front panel Palettes

  Data flow programming. Functions.

  LabVIEW Programming Structures (Formula, Case structure …)

  What is a subVI? Using a VI as a subVI.

  How to use LabVIEW with data acquisition (DAQ) software

Measurements and automation explorer (MAX)

I. Korolov: How to use LabVIEW

What is LabVIEW?


LabVIEW – Laboratory Virtual Instrument Engineering Workbench is a graphical (visual) programming from National istruments (NI).

The purpose is automating the usage of processing and measuring equipment in any laboratory setup.

Originally released for the Apple Macintosh in 1986, the graphical language at the heart of LabVIEW is called "G".

uses icons instead of lines of text to create programs

Dataflow programming language C language

Cross-platform

The graphical approach of LabVIEW allows non-programmers to build programs by dragging and dropping virtual representations of lab equipment with which they are already familiar.

Price

LabVIEW Professional Development System


Desktop PC

Laptop

PDA http://www.ni.com/labview/buy/

High-Speed Digitizers

High-Resolution Digitizers and DMMs

Multifunction Data Acquisition

Dynamic Signal Acquisition

Digital I/O Instrument Control

Counter/ Timers

Machine Vision

Motion Control

Distributed I/O and Embedded Control

Laptop PC PDA Desktop PC PXI Modular Instrumentation

Signal Conditioning and Switching

Unit Under Test

LabVIEW


www.ni.com

How does LabVIEW work?




Front panel Block Diagram

Ctrl+E

Block diagram toolbar

Reorder objects Run

Continuous run

Pause

Stop

Debugging features

Clean Up diagram



LabVIEW Front panel

Used to display Controls or Indicators



LabVIEW Block Diagram

- Actual program - Invisible to user - Read left to right

Example LP

How does LabVIEW work? Palettes


Front panel

Controls palette

Tools palette

Block Diagram

How does LabVIEW work? Tools palette

I. Korolov: How to use LabVIEW Example

Operating Tool

Positioning/Resizing Tool

Labeling Tool

Wiring Tool

Shortcut Menu Tool

•  Floating Palette •  Used to operate and modify front

panel and block diagram objects.

Scrolling Tool

Breakpoint Tool

Probe Tool

Color Copy Tool

Coloring Tool

Automatic Selection Tool

Data flow programming


Data flow programming


If you put a control (or indicator) on the front panel

LabVIEW automatically creates a corresponding control (or indicator) terminal on theBlock Diagram

Example FP TB

Data flow programming. Functions.


View as icon

Click and Ctrl+H “Add” function

wire

Example2,3

Data flow programming. Functions.


Data flow programming. Wires


Some of basic wires used in block diagrams

Data type Color

Floating-point orange

Integer blue

Boolean green

String Pink/purple

Dynamic Dark blue

Broken wires

The wire connects more than one data source

You have connected two terminals of different types

Data flow programming. Functions


Data flow programming. Functions


Polymorphism

Array Arithmetic Operations

Programming structures


LabVIEW Programming Structures


For loop

Right click

From 0 to N-1

Example For Loop



While loop

Repeats the sub diagram inside the loop until the conditional terminal receives a particular Boolean value

Auto-indexed tunnel

Loop tunnel

Shift register

Timed While loop

Example WhileL



Case structure

Example



Flat sequence structure

Stacked sequence structure

1 2 3

1 2

3 4

Sequence structures are used to ensure a subdiagram executes after or before another subdiagram



Use global variables to access and pass data among several VIs

Use local variables to read or write to one of the controls or indicators on the front panel of a VI.

Local variables Global variables

Example

LabVIEW: Wait statements


Wait Until Next ms Multiple function Wait (ms) function

Pre-loop code Loop code

LabVIEW: Graphs


Graph properties

Example Graph

LabVIEW: File I/O


Write to a File Read from a File

Write/Read LabVIEW Measurements file

Example File I/O

SubVI


What is a subVI? Using a VI as a subVI.


What is a subVI?

A SubVi is a stand VI that can be called by other VI and it is similar to an individual function.

Advantages Modular Easier to debug Don’t have to recreate code Require less memory



How to create a subVI?

A SubVi is a stand VI that can be called by other VI and it is similar to an individual function.

  Create/Edit the Icon   Create the Connector   Assign Terminals to controls and indicators   Add description (optional)   Save the VI   Insert the VI into a Top Level VI

1 Create/Edit the Icon

Right-click on the icon in the block diagram or front panel



2 Create the Connector Right click on the icon pane (front panel only)

3 Assign Terminals to controls and indicators

r

4 Documentation (VI properties)

5. Save the VI

6. Insert the VI into a Top Level VI

Example

Data acquisition


How to use LabVIEW with DAQ software


•  Data acquisition (DAQ) •  Connecting Signals •  Simple DAQ application

Sensors

Terminal Block

DAQ device

Fundamental task of a DAQ system is to measure or generate real-world physical signals

Measurements and automation explorer (MAX)


Measurement & Automation Explorer (MAX) provides access to all your NI DAQ, GPIB, IMAQ, IVI, Motion, VISA, and VXI devices. Here can configure your NI hardware and software, add new channels, interfaces, and virtual instruments, execute system diagnostics, and view the devices and instruments connected to your system.

Configuration tree Configuration View Task list

MAX is the primary configuration and testing utility that is available for the DAQ device

MAX



Traditional NI-DAQ Specific VIs for performing: •  Analog Input •  Analog Output •  Digital I/O •  Counter operations

NI-DAQmx Next generation driver: •  VIs for performing a task

•  One set of VIs for all measurement types

DAQ assistant Measurement type can be: •  Analog Input •  Analog Output •  Counter Input •  Counter Output •  Digital I/O



Ni USB 6501

Quickly and easily program the DAQ device Creates a local task Most applications can use the DAQ Assistant

DAQ assistant

Example DAQ

How to use LabVIEW ? Tips and tricks


  GPIB Communication and Configuration

  Virtual Instrument Software Architecture (VISA) Serial Port Communication

  Instrument Drivers (How to create and use *.dll in LabVIEW)

  Application control (property node and invoke node)

  How to execute a system command

  Remote panel connection manager and Web publishing tool

  …

Tips and tricks (3.03.2011)

Köszönöm for your attention!


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