6小时学会LabVIEW

nullVirtual Instrumentation With LabVIEWVirtual Instrumentation With LabVIEWCourse GoalsCourse GoalsUnderstand the components of a Virtual Instrument Introduce LabVIEW and common LabVIEW functions Build a simple data acquisition application Create a subroutine in LabVIEW Section ISection ILabVIEW terms Components of a LabVIEW application LabVIEW programming tools Creating an application in LabVIEWLabVIEW Programs Are Called Virtual Instruments (VIs)Front Panel Controls = Inputs Indicators = Outputs Block Diagram Accompanying “program” for front panel Components “wired” togetherLabVIEW Programs Are Called Virtual Instruments (VIs)VI Front PanelVI Front PanelBoolean ControlDouble IndicatorWaveform GraphPanel ToolbarVI Block DiagramVI Block DiagramNumeric ConstantThermometer TerminalCall to subVIWhile LoopKnob TerminalStop Button TerminalStop Loop TerminalTemperature GraphControls and Functions PalettesControls and Functions PalettesGraphical, floating palettes Used to place controls & indicators on the front panel, or to build the block diagramControls Palette (Panel Window)Functions Palette (Diagram Window)Tools PaletteOperating 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 ToolTools PaletteAutomatic Selection ToolStatus ToolbarRun Button Continuous Run Button Abort Execution Pause/Continue Button Text Settings Align Objects Distribute Objects ReorderExecution Highlighting Button Step Into Button Step Over Button Step Out Button Additional Buttons on the Diagram ToolbarStatus ToolbarnullDo Not Delete This SlideOpen and Run a Virtual InstrumentOpen and Run a Virtual Instrument Signal Generation and Processing.vi Help » Find Examples… Browse According to: Task Analyzing and Processing Signals Signal Processing Signal Generation and Processing.viCreating a VIControl Terminals Block Diagram WindowFront Panel WindowIndicator TerminalsCreating a VICreating a VI – Block DiagramCreating a VI – Block DiagramAfter Creating Front Panel Controls and Indicators, Switch to Block Diagram Move Front Panel Objects to Desired Locations Using the Position/Size/Select Tool Place Functions On Diagram Wire Appropriate Terminals Together to Complete the DiagramWiring Tips – Block DiagramWiring Tips – Block DiagramWiring “Hot Spot”Click While Wiring To Tack Wires DownSpacebar Flips Wire OrientationClick To Select WiresnullDo Not Delete This SlideDataflow ProgrammingDataflow ProgrammingBlock diagram does NOT execute left to right Node executes when data is available to ALL input terminals Nodes supply data to all output terminals when doneHelp OptionsHelp OptionsContext Help 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 directlynullDo Not Delete This SlideExercise 1 - Convert °C to °FExercise 1 - Convert °C to °FDebugging TechniquesDebugging TechniquesFinding Errors Execution Highlighting ProbeClick on broken Run button Window showing error appearsClick on Execution Highlighting button; data flow is animated using bubbles. Values are displayed on wires.Right-click on wire to display probe and it shows data as it flows through wire segment You can also select Probe tool from Tools palette and click on wireSection II – SubVIsSection II – SubVIsWhat is a subVI? Making an icon and connector for a subVI Using a VI as a subVISubVIsSubVIsA SubVI is a VI that can be used within another VI Advantages Modular Easier to debug Don’t have to recreate code Require less memoryIcon and ConnectorIcon and ConnectorAn icon represents a VI in other block diagrams A connector shows available terminals for data transfer SubVIsSubVIsSubVIsSteps to Create a SubVISteps to Create a SubVICreate the Icon Create the Connector Assign Terminals Save the VI Insert the VI into a Top Level VICreate the IconCreate the IconRight-click on the icon in the diagram or front panelCreate the ConnectorCreate the ConnectorRight click on the icon pane (front panel only)Assign TerminalsAssign TerminalsSave The VISave The VIChoose an Easy to Remember Location Organize by Functionality Save Similar VIs into one directory (e.g. Math Utilities) Organize by Application Save all VIs Used for a Specific Application into one 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 Insert the SubVI into a Top Level VIInsert the SubVI into a Top Level VIAccessing user-made subVIs Functions >> Select a VI Or Drag icon onto target diagramTips for Working in LabVIEWTips for Working in LabVIEWKeystroke Shortcuts – Activate/Deactivate Context Help Window – Remove Broken Wires From Block Diagram – Toggle Between Front Panel and Block Diagram – Undo (Also in Edit Menu) Tab Key – Toggle Through Tools on Toolbar Tools » Options… – Set Preferences in LabVIEW VI Properties – Configure VI Appearance, Documentation, etc.Section III – Data AcquisitionSection III – Data AcquisitionData acquisition (DAQ) basics Connecting Signals Simple DAQ applicationDAQ – Data AcquisitionDAQ – Data AcquisitionPlug-in board for a computer with: Analog input channels Analog output channels Counters Digital I/O Controlled by a suite of LabVIEW VIs Functions>>Data AcquisitionDAQ – Data AcquisitionDAQ – Data AcquisitionSimple Temperature Acquisition Example Two parameters Device = 1 Channel = 0Data Acquisition TerminologyData Acquisition TerminologyResolution - 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 RangenullDo Not Delete This SlideHardware ConnectionsHardware ConnectionsBNC-2120SCB-68SC-2075Exercise 2 – Simple Data AcquisitionExercise 2 – Simple Data AcquisitionComplete Convert C to F.vi, then create Thermometer.vi.nullDo Not Delete This SlideSection IV – Loops and ChartsSection IV – Loops and ChartsFor Loop While Loop Charts MultiplotsLoopsLoopsWhile Loops Have Iteration Terminal Always Run Once Run According to Continue TerminalFor Loops Have Iteration Terminal Run According to input NLoops (cont.)Loops (cont.)Select the loop Enclose Code to RepeatFor LoopChartsChartsWaveform chart – special numeric indicator that can display a history of values Controls >> Graphs >> Waveform ChartWiring Data into ChartsWiring Data into ChartsSingle Plot ChartsMultiplot ChartsExercise 3 – Monitoring Temperature Exercise 3 – Monitoring Temperature Students build Temperature Monitor.vi.Section V – Arrays & File I/OSection V – Arrays & File I/OBuild arrays manually Have LabVIEW build arrays automatically Write to a spreadsheet file Read from a spreadsheet fileAdding an Array to the Front PanelAdding an Array to the Front PanelFrom the Controls >> Array and Cluster subpalette, select the Array Shell Drop it on the screen.Adding an Array (cont.)Adding an Array (cont.)Place data object into shell (e.g. digital control).Creating an Array with a LoopCreating an Array with a LoopLoops accumulate arrays at their boundariesCreating 2D ArraysCreating 2D ArraysFile I/OFile I/ORead/write to spreadsheet file Read/write characters to file (ASCII) Read lines from file Read/write binary file Easy File I/O VIsnullDo Not Delete This SlideFile I/O ExampleFile I/O ExampleWriting a 2D Array to FileFile I/O ExampleFile I/O ExampleReading a 2D Array from a FileExercise 4 – Analyzing and Logging DataExercise 4 – Analyzing and Logging DataStudents build Temperature Logger.viSection VI – Array Functions & GraphsSection VI – Array Functions & GraphsBasic Array Functions Use graphs Create multiplots with graphsArray Functions – BasicsArray Functions – BasicsArray Functions – Build ArrayArray Functions – Build ArrayGraphsGraphsSelected from the Graph palette of Controls menuWaveform Graph – Plot an array of numbers against their indices XY Graph – Plot one array against another Digital Waveform Graph – Plot bits from binary datanullDo Not Delete This SlideGraphsGraphsRight-Click on the Graph to CustomizeExercise 5 – Using Waveform GraphsExercise 5 – Using Waveform GraphsSection VII – Strings, Clusters, & Error HandlingSection VII – Strings, Clusters, & Error Handling StringsStrings A string is a sequence of displayable or nondisplayable characters (ASCII) Many uses – displaying messages, instrument control, file I/O String control/indicator is in the Controls»String subpaletteClustersClustersData structure that groups data together Data may be of different types Analogous to struct in C Elements must be either all controls or all indicators Thought of as wires bundled into a cable Creating a ClusterCreating a Cluster1. Select a Cluster shell from the Array & Cluster subpalette2. Place objects inside the shellCluster FunctionsCluster FunctionsIn the Cluster subpalette of the Functions palette Can also be accessed by right-clicking on the cluster terminalBundle(Terminal labels reflect data type)Bundle By NameCluster FunctionsCluster FunctionsUnbundleUnbundle By NameUnbundled cluster in the diagramError ClustersError ClustersError cluster contains the following information: Boolean to report whether error occurred Integer to report a specific error code String to give information about the errorError Handling TechniquesError Handling TechniquesError information is passed from one subVI to the next If an error occurs in one subVI, all subsequent subVIs are not executed in the usual manner Error Clusters contain all error conditionserror clustersSection VIII - Case & Sequence Structures, Formula NodesSection VIII - Case & Sequence Structures, Formula NodesCase StructuresCase StructuresIn the Structures subpalette of Functions palette Enclose nodes or drag them inside the structure Stacked like a deck of cards, only one case visibleExercise 6 – Error Clusters & HandlingExercise 6 – Error Clusters & HandlingSequence StructuresSequence StructuresIn the Structures subpalette of Functions palette Executes diagrams sequentially, Frame 0 (0..x), where x is the total number of frames Stacked like a deck of cards, only one frame visibleSequence LocalsSequence LocalsPass data from one frame to future frames Created at the border of the Sequence structureSequence local created in Frame 1Data not availableData availableFormula NodesFormula NodesIn the Structures subpalette Implement complicated equations Variables created at border Variable names are case sensitive Each statement must terminate with a semicolon (;) Context Help Window shows available functionsNote semicolonSection IX – Printing & DocumentationSection IX – Printing & DocumentationPrint From File Menu to Printer, HTML, Rich Text File Programmatically Print Graphs or Front Panel Images Document VIs in VI Properties » Documentation Dialog Add Comments Using Free Labels on Front Panel & Block DiagramPrintingPrintingFile » Print… Gives Many Printing Options Choose to Print Icon, Front Panel, Block Diagram, VI Hierarchy, Included SubVIs, VI History Print Panel.vi (Functions » Application Control) Programmatically Prints a Front Panel Generate & Print Reports (Functions » Report Generation) Search in Find Examples for Report GenerationDocumenting VIsDocumenting VIsVI Properties » Documentation Provide a Description and Help Information for a VI VI Properties » Revision History Track Changes Between Versions of a VI Individual Controls » Description and Tip… Right Click to Provide Description and Tip Strip Use Labeling Tool to Document Front Panels & Block DiagramsSection X – Basic Programming ArchitectureSection X – Basic Programming ArchitectureSimple VI Architecture General VI Architecture State Machine Architecture Simple VI ArchitectureSimple VI ArchitectureFunctional VI that produces results when run No “start” or “stop” options Suitable for lab tests, calculations Example: Convert C to F.viGeneral VI ArchitectureGeneral VI ArchitectureThree Main Steps Startup Main Application ShutdownState Machine ArchitectureState Machine ArchitectureAdvantages Can go from any state from any other Easy to modify and debug Disadvantages Can lose events if two occur at the same timeStates: 0: Startup 1: Idle 2: Event 1 3: Event 2 4: ShutdownExercise 7 – Simple State MachineExercise 7 – Simple State MachinenullDo Not Delete This SlideSection XI – Remote Front PanelsSection XI – Remote Front PanelsView & Control LabVIEW Front Panels from a Web Browser Requires no programming Remote clients see “live” front panel updates Multiple clients can view the same panel simultaneously Only one client can control the front panel at a timeRemote Panel Web Publishing ToolRemote Panel Web Publishing ToolTools » Web Publishing Tool…Click Save to Disk and VI is Embedded into an Html File After File is Saved, It Can Be Reopened and Customized in Any Html EditorRemote Front Panels - ResourcesRemote Front Panels - ResourcesNI Developer Zone (zone.ni.com) Search for Remote Front Panel Tutorials & Instructions Are Available for Download Information on Incorporating Web Cameras into Remote Panel ApplicationsSection XII – Additional TopicsSection XII – Additional TopicsProperty Nodes Local Variables Global Variables DataSocket Binary File I/OWhere Do I Go From Here?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/) Instrument Driver Library (www.ni.com/idnet)