How to use LabVIEW. Ihor Korolov

Transcription

1 How to use LabVIEW Ihor Korolov February 2011

2 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)

3 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". C language Dataflow programming language uses icons instead of lines of text to create programs 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. Cross-platform

4 Price Desktop PC LabVIEW Professional Development System Laptop PDA

5 LabVIEW PXI Modular Instrumentation Desktop PC Laptop PC PDA High-Speed Digitizers High-Resolution Digitizers and DMMs Multifunction Data Acquisition Dynamic Signal Acquisition Instrument Control Digital I/O Counter/ Timers Machine Vision Motion Control Distributed I/O and Embedded Control Signal Conditioning and Switching Unit Under Test

6 How does LabVIEW work?

7 How does LabVIEW work?

8 How does LabVIEW work? Front panel Block Diagram Ctrl+E Continuous run Pause Block diagram toolbar Clean Up diagram Run Stop Debugging features Reorder objects

9 How does LabVIEW work? LabVIEW Front panel Used to display Controls or Indicators

10 How does LabVIEW work? LabVIEW Block Diagram - Actual program - Invisible to user - Read left to right Example LP

11 How does LabVIEW work? Palettes Controls palette Front panel Block Diagram Tools palette

12 How does LabVIEW work? Tools palette Floating Palette Used to operate and modify front panel and block diagram objects. Automatic Selection Tool Operating Tool Positioning/Resizing Tool Labeling Tool Wiring Tool Shortcut Menu Tool Scrolling Tool Breakpoint Tool Probe Tool Color Copy Tool Coloring Tool Example

13 Data flow programming

14 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

15 Data flow programming. Functions. View as icon Click and Ctrl+H Add function wire Example2,3

16 Data flow programming. Functions. Example

17 Data flow programming. Wires Some of basic wires used in block diagrams Data type Floating-point Integer Boolean String Dynamic Color orange blue green Pink/purple Dark blue Broken wires The wire connects more than one data source You have connected two terminals of different types

18 Data flow programming. Functions Example

19 Data flow programming. Functions Polymorphism Array Arithmetic Operations

20 Programming structures

21 LabVIEW Programming Structures For loop From 0 to N-1 Right click Example For Loop

22 LabVIEW Programming Structures While loop Auto-indexed tunnel Loop tunnel Shift register Timed While loop Repeats the sub diagram inside the loop until the conditional terminal receives a particular Boolean value Example WhileL

23 LabVIEW Programming Structures Case structure Example

24 LabVIEW Programming Structures Flat sequence structure Stacked sequence structure Sequence structures are used to ensure a subdiagram executes after or before another subdiagram

25 LabVIEW Programming Structures Local variables Global variables Use local variables to read or write to one of the controls or indicators on the front panel of a VI. Use global variables to access and pass data among several VIs Example

26 LabVIEW: Wait statements Wait (ms) function Wait Until Next ms Multiple function Pre-loop code Loop code

27 LabVIEW: Graphs Graph properties Example Graph

28 LabVIEW: File I/O Write to a File Read from a File Write/Read LabVIEW Measurements file Example File I/O

29 SubVI

30 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

31 What is a subvi? Using a VI as a subvi. 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

32 What is a subvi? Using a VI as a subvi. 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

33 Data acquisition

34 How to use LabVIEW with DAQ software Fundamental task of a DAQ system is to measure or generate real-world physical signals Data acquisition (DAQ) Connecting Signals Simple DAQ application DAQ device Sensors Terminal Block

35 Measurements and automation explorer (MAX) MAX is the primary configuration and testing utility that is available for the DAQ device 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

36 How to use LabVIEW with DAQ software 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

37 How to use LabVIEW with DAQ software Ni USB 6501 DAQ assistant Quickly and easily program the DAQ device Creates a local task Most applications can use the DAQ Assistant Example DAQ

38 How to use LabVIEW? Tips and tricks 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

39 Köszönöm for your attention!