Lab view introduction-threehour
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Virtual Instrumentation With LabVIEW is a course that introduces students to LabVIEW and building virtual instruments (VIs). The course covers the components of VIs, creating simple applications, using loops and charts, and performing data acquisition and file input/output. Students will understand LabVIEW programming tools and terms, build interactive front panels, use functions and structures on block diagrams, create subVIs, and log sensor data to files. Exercises include converting temperatures, making a thermometer, using loops, and building a temperature data logger.
Lab view introduction-threehour
- 1. Virtual Instrumentation With LabVIEW
- 2. Course Goals • Understand the components of a Virtual Instrument • Introduce LabVIEW and common LabVIEW functions • Build a simple data acquisition application • Create a subroutine in LabVIEW
- 3. Section I • LabVIEW terms • Components of a LabVIEW application • LabVIEW programming tools • Creating an application in LabVIEW
- 4. LabVIEW Programs Are Called Virtual Instruments (VIs) Front Panel • Controls = Inputs • Indicators = O Outputs Block Diagram • Accompanying “program” program for front panel • Components “wired” together
- 5. VI Front Panel Front Panel Toolbar Boolean Control Icon Graph G h Legend Waveform Graph Plot Legend L d Scale Legend L d
- 6. VI Block Diagram g Block Diagram Toolbar Divide Function SubVI Graph Terminal Wire Data While Loop Structure Numeric Constant Timing Function Boolean Control Terminal
- 7. Express VIs, VIs and Functions • Express VIs: interactive VIs with configurable dialog page • Standard VIs: modularized VIs customized by wiring p g • Functions: fundamental operating elements of LabVIEW; no front panel or block diagram Function Express VI Standard VI
- 8. Controls and Functions Palettes Controls Palette (Front Panel Window) Functions Palette (Block Diagram Window)
- 9. Tools Palette • Floating Palette • Used to operate and modify front panel and block diagram objects. j Automatic Selection Tool Operating Tool Scrolling Tool Positioning/Resizing Tool Breakpoint Tool Labeling Tool Probe Tool Wiring Tool Color Copy Tool Shortcut Menu Tool Coloring Tool
- 10. Status Toolbar Run Button R B tt Continuous Run Button Additional Buttons on the Diagram Toolbar g Abort Execution Pause/Continue Button Text Settings Align Objects Distribute Objects Reorder Resize front panel objects Execution Highlighting Button Step Into Button Step Over Button Step Out Button
- 11. Open and Run a Virtual Instrument Example finder
- 12. Creating a VI Front Panel Window Block Diagram Window Control Terminals Indicator Terminals
- 13. Creating a VI – Block Diagram g g
- 14. Wiring Tips – Block Diagram Wiring “Hot Spot” Use Automatic Wire Routing Click To Select Wires Clean Up Wiring
- 15. Dataflow Programming g g • Block diagram executes dependent on the flo of data flow data; block diagram does NOT execute left to right • N d executes when data is Node t h d t i available to ALL input terminals • Nodes supply data to all output terminals h done t i l when d
- 16. Help Options Context Help C t tH l • • • • Online help Lock help Simple/Complex Diagram help Ctrl + H Online reference • All menus online • Pop up on functions in diagram to access online info directly
- 17. Exercise 1 - Convert °C to °F C F
- 18. Debugging Techniques • Finding Errors Click on broken Run button Window showing error appears • Execution Highlighting Click on Execution Highlighting button; data g flow is animated using bubbles. Values are displayed on wires. • Probe Right-click Ri ht li k on wire to display probe and it i t di l b d shows data as it flows through wire segment You can also select Probe tool from Tools palette and click on wire
- 19. Section II – SubVIs • What is a subVI? • Making an icon and connector for a subVI • Using a VI as a s bVI subVI
- 20. Block Diagram Nodes Icon • • • • Expandable Node Function Generator VI Same VI, viewed three different ways Yellow field designates a standard VI Blue field designates an Express VI Expanded Node
- 21. SubVIs • A SubVI is a VI that can be used within another VI • Similar to a subroutine g • Advantages – Modular – Easier to debug as e – Don’t have to recreate code – Require less memory
- 22. Icon and Connector Icon Terminals Connector • An icon represents a VI in other block diagrams di • A connector shows available terminals for data transfer
- 23. SubVIs Sub VIs S b VI
- 24. Steps to Create a SubVI • Create the Icon • Create the Connector • Assign Terminals • Save the VI • Insert the VI into a Top Level VI
- 25. Create the Icon • Right-click on the icon in the block diagram or front panel
- 26. Create the Connector Right click on the icon pane (front panel only)
- 27. Assign Terminals
- 28. Save The VI • Choose an Easy to Remember Location y • Organize by Functionality – Save Similar VIs into one directory (e g Math Utilities) (e.g. • Organize by Application –S Save all VI U d f a S ll VIs Used for Specific A li ti i t one ifi Application into directory or library file (e.g. Lab 1 – Frequency Response) • Library Files (.llbs) combine many VI’s into a single file, ideal for transferring entire applications across computers
- 29. Insert the SubVI into a Top Level VI Accessing user-made subVIs Functions >>All Functions >> Select a VI Or Drag i D icon onto target di diagram
- 30. Tips for Working in LabVIEW • Keystroke Shortcuts y – <Ctrl-H> – Activate/Deactivate Context Help Window – <Ctrl-B> – Remove Broken Wires From Block Diagram Ctrl B – <Ctrl-E> – Toggle Between Front Panel and Block Diagram g – <Ctrl-Z> – Undo (Also in Edit Menu) • Tools » Options… – Set Preferences in LabVIEW • VI Properties – Configure VI Appearance, Documentation, etc. Documentation etc
- 31. Section III – Data Acquisition • Data acquisition (DAQ) basics • Connecting Signals • Simple DAQ application DAQ Device Computer Sensors Cable Terminal Block
- 32. DAQ – Data Acquisition Temperature Acquisition using the DAQ Assistant
- 33. Data Acquisition Terminology • Resolution - Determines How Many Different Voltage Changes Can Be Measured – Larger Resolution More Precise Representation of Signal • Range - Minimum and Maximum Voltages – Smaller range More Precise Representation of Signal • Gain - Amplifies or Attenuates Signal for Best Fit in Range
- 35. Exercise 2 – Simple Data Acquisition Complete Convert C to F.vi, then create Thermometer.vi.
- 36. Section IV – Loops and Charts • For Loop p • While Loop • Charts • Multiplots
- 37. Loops • While Loops p – Have Iteration Terminal – Always Run at least Once – Run According to Conditional Terminal • For Loops – Have Iteration Terminal – Run According to input N of Count Terminal
- 38. Loops (cont.) p ( ) 1. Select the loop 2. Enclose code to be repeated 3. Drop or drag additional nodes and then wire
- 39. Charts Waveform chart – special numeric indicator that can display a history of values Controls >> Graph Indicators >> Waveform Chart
- 40. Wiring Data into Charts Single Plot Charts g Multiplot Charts p
- 41. Exercise 3 – Using loops Students build Use a loop.vi.
- 42. Section V – Arrays & File I/O • Build arrays manually • Have LabVIEW build arrays automatically p • Write to a spreadsheet file • Read from a spreadsheet file
- 43. Adding an Array to the Front Panel From the Controls >> All Controls >> Array and Cluster b l tt Cl t subpalette, select th A l t the Array Sh ll Shell Drop it on the screen.
- 44. Adding an Array (cont.) Place data object into shell ( j (i.e. Numeric Control) )
- 45. Creating an Array with a Loop • Loops accumulate arrays at their boundaries p y
- 47. File I/O File I/O – passing data to and from files - Files can be binary, text, or spreadsheet ( ) - Write/Read LabVIEW Measurements file (*.lvm) Writing to LVM file Reading from LVM file
- 48. Write LabVIEW Measurement File • Includes the open, write, close and error handling functions • Handles f formatting the string with either a tab or comma delimiter • Merge Signals function is used to combine data into the dynamic data type
- 49. Exercise 4 – Analyzing and Logging Data Students build Temperature Logger.vi
- 50. Where Do I Go From Here? • Example programs (Help» Find Examples…) • LabVIEW Student Edition (www.ni.com/labviewse) • Web resources (ni.com) – NI Developer Zone (zone.ni.com) – Application Notes – Info labview newsgroup (www info labview org/) Info-labview (www.info-labview.org/) – Instrument Driver Library (www.ni.com/idnet)