Introduction to LabVIEW

UniversityCollegeofSoutheastNorway
IntroductiontoLabVIEW
Hans-PetterHalvorsen,2016-09-07
http://home.hit.no/~hansha
Preface
ThisdocumentexplainsthebasicconceptsofLabVIEW.
Youfindadditionalresources,code,etc.here:
http://home.hit.no/~hansha/?tutorial=labview
YouneedtoinstalltheLabVIEWProfessionalDevelopmentSystem.
FormoreinformationaboutLabVIEW,visitmyBlog:http://home.hit.no/~hansha/
LabVIEWBasicsVideos:
http://home.hit.no/~hansha/video/labview_basics.php LabVIEWTrainingandResources:
http://home.hit.no/~hansha/?training=labview ii
TableofContents
Preface......................................................................................................................................ii
TableofContents.....................................................................................................................iii
1
2
Introduction......................................................................................................................1
1.1
DataflowProgramming...............................................................................................1
1.2
GraphicalProgramming..............................................................................................1
1.3
Benefits.......................................................................................................................2
StartusingLabVIEW..........................................................................................................4
2.1
TheLabVIEWEnvironment.........................................................................................4
2.2
FrontPanel.................................................................................................................5
2.3
BlockDiagram.............................................................................................................7
2.4
ControlsPalette........................................................................................................10
2.4.1
NumericSubPalette..........................................................................................12
2.4.2
BooleanSubPalette..........................................................................................12
2.4.3
String&PathSubPalette..................................................................................13
2.5
FunctionPalette........................................................................................................13
2.6
ToolsPalette.............................................................................................................14
2.7
Wiring.......................................................................................................................16
2.8
Toolbar......................................................................................................................16
2.9
Execution..................................................................................................................17
2.10
TheObjectsshort-cutmenu.................................................................................18
2.11
DataflowProgramming.........................................................................................19
2.12
Help.......................................................................................................................20
Exercises..............................................................................................................................20
iii
iv
3
TableofContents
SubVIs.............................................................................................................................24
3.1
CreateNewSubVIfromScratch...............................................................................25
3.1.1
InputandOutputSubVIConnectors.................................................................26
3.1.2
IconEditor.........................................................................................................28
3.2
CreateSubVIfromexistingcode..............................................................................29
3.3
UsingSubVIs............................................................................................................30
Exercises..............................................................................................................................31
4
CustomizeLabVIEW.........................................................................................................33
Exercises..............................................................................................................................34
5
LoopsandStructures.......................................................................................................35
5.1
Loops.........................................................................................................................35
5.1.1
ForLoop.............................................................................................................36
5.1.2
WhileLoop........................................................................................................37
5.2
Structures.................................................................................................................38
5.2.1
CaseStructure...................................................................................................38
5.2.2
SequenceStructure...........................................................................................39
5.2.3
EventStructure..................................................................................................40
Exercises..............................................................................................................................42
6
TroubleshootingandDebugging.....................................................................................45
6.1
Howtofinderrors....................................................................................................45
6.2
HighlightExecution...................................................................................................45
6.3
Probes.......................................................................................................................46
6.4
Breakpoints...............................................................................................................47
6.5
Stepinto/over/outdebugging..................................................................................48
Exercises..............................................................................................................................48
Tutorial:AnIntroductiontoLabVIEW
v
7
TableofContents
WorkingwithData..........................................................................................................50
7.1
Arrays........................................................................................................................50
7.1.1
Auto-Indexing....................................................................................................50
7.1.2
ArrayFunctions.................................................................................................51
7.2
Cluster.......................................................................................................................53
7.2.1
ClusterOrder.....................................................................................................54
7.2.2
ClusterElements................................................................................................55
Exercises..............................................................................................................................56
8
WorkingwithStrings.......................................................................................................58
Exercises..............................................................................................................................60
9
ErrorHandling.................................................................................................................62
9.1
FindingError.............................................................................................................62
9.2
ErrorWiring..............................................................................................................62
9.3
ErrorHandlinginSubVIs...........................................................................................63
9.4
ErrorHandling...........................................................................................................64
Exercises..............................................................................................................................65
10
WorkingwithProjects..................................................................................................66
10.1
ProjectExplorer.....................................................................................................66
10.2
Deployment...........................................................................................................67
Exercises..............................................................................................................................69
11
DesignTechniques........................................................................................................71
11.1
ForceProgramFlow..............................................................................................71
11.2
ShiftRegister.........................................................................................................72
11.3
StateProgrammingArchitecture..........................................................................73
11.4
MultipleLoops/Parallelprogramming..................................................................75
Tutorial:AnIntroductiontoLabVIEW
vi
11.5
TableofContents
Templates..............................................................................................................77
Exercises..............................................................................................................................78
12
UserInterface...............................................................................................................80
12.1
VIProperties.........................................................................................................81
Exercises..............................................................................................................................84
13
PlottingData.................................................................................................................85
13.1
Customizing...........................................................................................................87
Exercises..............................................................................................................................89
14
Tips&Tricks.................................................................................................................91
14.1
10functionsyouneedtoknowabout..................................................................91
14.2
The10mostusefulShort-cuts..............................................................................96
15
ExampleApplication.....................................................................................................97
16
AdditionalExercises...................................................................................................101
17
What’sNext?..............................................................................................................106
17.1
MyBlog...............................................................................................................106
17.2
Tutorials..............................................................................................................106
17.3
AdditionalResources..........................................................................................106
17.4
Examples.............................................................................................................107
QuickReference....................................................................................................................108
Tutorial:AnIntroductiontoLabVIEW
1 Introduction
LabVIEW(shortforLaboratoryVirtualInstrumentationEngineeringWorkbench)isa
platformanddevelopmentenvironmentforavisualprogramminglanguagefromNational
Instruments.Thegraphicallanguageisnamed"G".OriginallyreleasedfortheApple
Macintoshin1986,LabVIEWiscommonlyusedfordataacquisition,instrumentcontrol,and
industrialautomationonavarietyofplatformsincludingMicrosoftWindows,variousflavors
ofUNIX,Linux,andMacOSX.ThelatestversionofLabVIEWisversionLabVIEW2011.Visit
NationalInstrumentsatwww.ni.com.
Thecodefileshavetheextension“.vi”,whichisanabbreviationfor“VirtualInstrument”.
LabVIEWofferslotsofadditionalAdd-OnsandToolkits.
1.1 DataflowProgramming
TheprogramminglanguageusedinLabVIEW,alsoreferredtoasG,isadataflow
programminglanguage.Executionisdeterminedbythestructureofagraphicalblock
diagram(theLV-sourcecode)onwhichtheprogrammerconnectsdifferentfunction-nodes
bydrawingwires.Thesewirespropagatevariablesandanynodecanexecuteassoonasall
itsinputdatabecomeavailable.Sincethismightbethecaseformultiplenodes
simultaneously,Gisinherentlycapableofparallelexecution.Multi-processingandmultithreadinghardwareisautomaticallyexploitedbythebuilt-inscheduler,whichmultiplexes
multipleOSthreadsoverthenodesreadyforexecution.
1.2 GraphicalProgramming
LabVIEWtiesthecreationofuserinterfaces(calledfrontpanels)intothedevelopmentcycle.
LabVIEWprograms/subroutinesarecalledvirtualinstruments(VIs).EachVIhasthree
components:ablockdiagram,afrontpanel,andaconnectorpanel.Thelastisusedto
representtheVIintheblockdiagramsofother,callingVIs.Controlsandindicatorsonthe
frontpanelallowanoperatortoinputdataintoorextractdatafromarunningvirtual
instrument.However,thefrontpanelcanalsoserveasaprogrammaticinterface.Thusa
virtualinstrumentcaneitherberunasaprogram,withthefrontpanelservingasauser
interface,or,whendroppedasanodeontotheblockdiagram,thefrontpaneldefinesthe
inputsandoutputsforthegivennodethroughtheconnectorpane.ThisimplieseachVIcan
beeasilytestedbeforebeingembeddedasasubroutineintoalargerprogram.
1
2
Introduction
Thegraphicalapproachalsoallowsnon-programmerstobuildprogramssimplybydragging
anddroppingvirtualrepresentationsoflabequipmentwithwhichtheyarealreadyfamiliar.
TheLabVIEWprogrammingenvironment,withtheincludedexamplesandthe
documentation,makesitsimpletocreatesmallapplications.Thisisabenefitononeside,
butthereisalsoacertaindangerofunderestimatingtheexpertiseneededforgoodquality
"G"programming.Forcomplexalgorithmsorlarge-scalecode,itisimportantthatthe
programmerpossessanextensiveknowledgeofthespecialLabVIEWsyntaxandthe
topologyofitsmemorymanagement.ThemostadvancedLabVIEWdevelopmentsystems
offerthepossibilityofbuildingstand-aloneapplications.Furthermore,itispossibletocreate
distributedapplications,whichcommunicatebyaclient/serverscheme,andaretherefore
easiertoimplementduetotheinherentlyparallelnatureofG-code.
1.3 Benefits
OnebenefitofLabVIEWoverotherdevelopmentenvironmentsistheextensivesupportfor
accessinginstrumentationhardware.Driversandabstractionlayersformanydifferenttypes
ofinstrumentsandbusesareincludedorareavailableforinclusion.Thesepresent
themselvesasgraphicalnodes.Theabstractionlayersofferstandardsoftwareinterfacesto
communicatewithhardwaredevices.Theprovideddriverinterfacessaveprogram
developmenttime.ThesalespitchofNationalInstrumentsis,therefore,thatevenpeople
withlimitedcodingexperiencecanwriteprogramsanddeploytestsolutionsinareduced
timeframewhencomparedtomoreconventionalorcompetingsystems.Anewhardware
drivertopology(DAQmxBase),whichconsistsmainlyofG-codedcomponentswithonlya
fewregistercallsthroughNIMeasurementHardwareDDK(DriverDevelopmentKit)
functions,providesplatformindependenthardwareaccesstonumerousdataacquisition
andinstrumentationdevices.TheDAQmxBasedriverisavailableforLabVIEWonWindows,
MacOSXandLinuxplatforms.
Thisdocumentintroducingthefollowingthemes:
•
•
•
•
•
StartusingLabVIEW
o TheLabVIEWEnvironment
o FrontPanelandBlockDiagram
o Palettes:ControlPalette,FunctionsPalette,ToolsPalette
o DataTypes
o PropertyNodes
SubVIs
LoopsandStructures
TroubleshootingandDebugging
WorkingwithData
Tutorial:AnIntroductiontoLabVIEW
3
•
•
•
•
•
•
•
•
•
•
Introduction
o Arrays
§ ArrayFunctions
o Cluster
WorkingwithStrings
ErrorHandling
WorkingwithProjectsusingProjectExplorer
DesignTechniques
o ShiftRegister
o StateMachine
o MultipleLoops
UserInterface
PlottingData
Deployment:BuildingExecutableApplications(.exe)
IntroductiontoAdd-OnsandToolkits
o Brieflyexplanations…
o MoredetailaboutControlandSimulationModuleinlater
IntroductiontoDAQ-DataAcquisition
o MAX–MeasurementandAutomationExplorer
o NI-DAQmx
QuickReferencewithKeyboardShort-cuts
FormoreinformationaboutLabVIEW,visitmyBlog:http://home.hit.no/~hansha/
Tutorial:AnIntroductiontoLabVIEW
2 StartusingLabVIEW
ThischapterexplainsthebasicconceptsinLabVIEW.
Thetopicsareasfollows:
•
•
•
•
•
TheLabVIEWEnvironment
FrontPanelandBlockDiagram
Palettes:ControlPalette,FunctionsPalette,ToolsPalette
DataTypes
PropertyNodes
2.1 TheLabVIEWEnvironment
LabVIEWprogramsarecalledVirtualInstruments,orVIs,becausetheirappearanceand
operationimitatephysicalinstruments,suchasoscilloscopesandmultimeters.LabVIEW
containsacomprehensivesetoftoolsforacquiringanalyzing,displaying,andstoringdata,as
wellastoolstohelpyoutroubleshootyourcode.
WhenopeningLabVIEW,youfirstcometothe“GettingStarted”window.
4
5
StartusingLabVIEW InordertocreateanewVI,select“BlankVI”orinordertocreateanewLabVIEWproject,
select“Emptyproject”.
WhenyouopenablankVI,anuntitledfrontpanelwindowappears.Thiswindowdisplays
thefrontpanelandisoneofthetwoLabVIEWwindowsyouusetobuildaVI.Theother
windowcontainstheblockdiagram.Thesectionsbelowdescribethefrontpanelandthe
blockdiagram.
2.2 FrontPanel
WhenyouhavecreatedanewVIorselectedanexistingVI,theFrontPanelandtheBlock
DiagramforthatspecificVIwillappear.
InLabVIEW,youbuildauserinterface,orfrontpanel,withcontrolsandindicators.Controls
areknobs,pushbuttons,dials,andotherinputdevices.Indicatorsaregraphs,LEDs,and
otherdisplays.
Youbuildthefrontpanelwithcontrolsandindicators,whicharetheinteractiveinputand
outputterminalsoftheVI,respectively.Controlsareknobs,pushbuttons,dials,andother
inputdevices.Indicatorsaregraphs,LEDs,andotherdisplays.Controlssimulateinstrument
Tutorial:AnIntroductiontoLabVIEW
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StartusingLabVIEW inputdevicesandsupplydatatotheblockdiagramoftheVI.Indicatorssimulateinstrument
outputdevicesanddisplaydatatheblockdiagramacquiresorgenerates.
E.g.,a“Numeric”caneitherbea“NumericControl”ora“NumericIndicator”,asseenbelow.
Iyouselecta“NumericControl”,itcaneasybechangedtoan“NumericIndicator”byright
clickontheobjectanselect“ChangetoIndicator”
Oropposite,Iyouselecta“NumericIndicator”,itcaneasybechangedtoan“Numeric
Control”byrightclickontheobjectanselect“ChangetoControl”
Tutorial:AnIntroductiontoLabVIEW
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StartusingLabVIEW Thedifferencebetweena“NumericControl”anda“NumericIndicator”isthatfora
“NumericControl”youmayenteravalue,whilethe“NumericIndicator”isread-only,i.e.,
youmayonlyreadthevalue,notchangeit.
Theappearanceisalsoslightlydifferent,the“NumericControl”hasanincrementandan
decrementbuttoninfront,whilethe“NumericIndicator”hasadarkerbackgroundcolorin
ordertoindicatethatitsread-only.
2.3 BlockDiagram
Afteryoubuildtheuserinterface,youaddcodeusingVIsandstructurestocontrolthefront
panelobjects.Theblockdiagramcontainsthiscode.Insomeways,theblockdiagram
resemblesaflowchart.
Tutorial:AnIntroductiontoLabVIEW
8
StartusingLabVIEW Afteryoubuildthefrontpanel,youaddcodeusinggraphicalrepresentationsoffunctionsto
controlthefrontpanelobjects.Theblockdiagramcontainsthisgraphicalsourcecode.Front
panelobjectsappearasterminals,ontheblockdiagram.Blockdiagramobjectsinclude
terminals,subVIs,functions,constants,structures,andwires,whichtransferdataamong
otherblockdiagramobjects.
TheFigurebelowshowsafrontpanelanditscorrespondingblockdiagramwithfrontpanel
andblockdiagramcomponents.
Tutorial:AnIntroductiontoLabVIEW
9
StartusingLabVIEW Thedifferentcomponentsareasfollows:
1. Toolbar
2. OwnedLabel
3. NumericControl
4. FreeLabel
5. NumericControlTerminal
6. KnobTerminal
7. NumericConstant
8. MultiplyFunction
9. Icon
10. KnobControl
11. PlotLegend 12. XYGraph
Tutorial:AnIntroductiontoLabVIEW
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StartusingLabVIEW 13. WireDataPath
14. XYGraphTerminal
15. BundleFunction
16. SubVI
17. ForLoopStructure
2.4 ControlsPalette
TheControlsandFunctionspalettescontainsubpalettesofobjectsyoucanusetocreatea
VI.Whenyouclickasubpaletteicon,theentirepalettechangestothesubpaletteyou
selected.Touseanobjectonthepalettes,clicktheobjectandplaceitonthefrontpanelor
blockdiagram.TheControlspaletteisavailableonlyonthefrontpanel.TheControlspalette
containsthecontrolsandindicatorsyouusetobuildthefrontpanel.
ThemostusedSubPalettesaretheNumericSubPalette,theBooleanSubPaletteandthe
String&PathSubPalette.
YoumaychangetheappearanceandthecontentsoftheControlspalette:
Tutorial:AnIntroductiontoLabVIEW
11
StartusingLabVIEW YoumayPinthepalette,soitisalwaysvisible,justclickthelittlepinbutton
upperleftcornerofthepalette:
inthe
Ifyouwanttochangethecontentandappearanceofthepalette,clickthe“View”button.
Hereyoumaychangethewaythepaletteshouldlook. Ifyouclick“ChangeVisibleCategories…”youmaychangewhichCategoriesyouwanttohave
visible.
Tutorial:AnIntroductiontoLabVIEW
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2.4.1
StartusingLabVIEW NumericSubPalette
“NumericalControl”and“NumericalIndicator”arethemostusedobjectsinthenumericsub
palette.
2.4.2
BooleanSubPalette
Thispalettehaslotsofdifferentbuttonsyoumayuse.OK,CancelandStopbuttonsare
useful.
Tutorial:AnIntroductiontoLabVIEW
13
StartusingLabVIEW 2.4.3
String&PathSubPalette
IntheStringandPathpalettewehaveStringControls,ComboBox,etc.
2.5 FunctionPalette
TheFunctionspaletteisavailableonlyontheblockdiagram.TheFunctionspalettecontains
theVIsandfunctionsyouusetobuildtheblockdiagram.
Tutorial:AnIntroductiontoLabVIEW
14
StartusingLabVIEW 2.6 ToolsPalette
Youcancreate,modify,anddebugVIsusingthetoolslocatedonthefloatingToolspalette.
TheToolspaletteisavailableonboththefrontpanelandtheblockdiagram.Atoolisa
specialoperatingmodeofthemousecursor.Thecursorcorrespondstotheiconofthetool
selectedintheToolspalette.Usethetoolstooperateandmodifyfrontpanelandblock
diagramobjects.
Tutorial:AnIntroductiontoLabVIEW
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StartusingLabVIEW TheToolspaletteisavailablefromtheViewmenu:
Ifyoumakesure“Automaticwiring”isdisabled(Irecommendyoudoso!)youmayuse
theTabkeyonyourkeyboardinordertoswitchbetweenthemostcommontools.
Themostusedtoolsare:
UsetheOperatingtool,shownatleft,tochangethevaluesofacontrolorselect
thetextwithinacontrol.TheOperatingtoolchangestotheiconshownatleftwhenit
movesoveratextcontrol,suchasanumericorstringcontrol.
UsethePositioningtool,shownatleft,toselect,move,orresizeobjects.The
Positioningtoolchangestoresizinghandleswhenitmovesovertheedgeofaresizable
object.
UsetheLabelingtool,shownatleft,toedittextandcreatefreelabels.The
Labelingtoolchangestothefollowingicon
whenyoucreatefreelabels.
UsetheWiringtool,shownatleft,towireobjectstogetherontheblockdiagram.
Tutorial:AnIntroductiontoLabVIEW
16
StartusingLabVIEW 2.7 Wiring
InordertocreatethelogicalflowbetweentheobjectontheBlockDiagram,youneedtouse
theWiringtoolinordertoconnectthedifferentobjectstogether.
UsetheWiringtooltowireobjectstogetherontheblockdiagram.
AvailableKeyboardShortcutswhendealingwithWiring:
Ctrl-Bisveryuseful.Thisshort-cutremovesallbrokenwiresontheBlockDiagram.
2.8 Toolbar
BelowweseetheLabVIEWToolbar:
Thebehaviorsofthedifferentbuttonsareasfollows:
Tutorial:AnIntroductiontoLabVIEW
17
StartusingLabVIEW ClicktheRunbuttontorunaVI.LabVIEWcompilestheVI,ifnecessary.YoucanrunaVI
iftheRunbuttonappearsasasolidwhitearrow.Thesolidwhitearrow,shownabove,also
indicatesyoucanusetheVIasasubVIifyoucreateaconnectorpanefortheVI.
WhiletheVIruns,theRunbuttonappearsasshownatleftiftheVIisatop-levelVI,
meaningithasnocallersandthereforeisnotasubVI.
IftheVIthatisrunningisasubVI,theRunbuttonappearsasshownatleft.
TheRunbuttonappearsbroken,shownatleft,whentheVIyouarecreatingorediting
containserrors.IftheRunbuttonstillappearsbrokenafteryounishwiringtheblock
diagram,theVIisbrokenandcannotrun.ClickthisbuttontodisplaytheErrorlistwindow,
whichlistsallerrorsandwarnings.
ClicktheRunContinuouslybutton,shownatleft,toruntheVIuntilyouabortorpause
execution.Youalsocanclickthebuttonagaintodisablecontinuousrunning.
WhiletheVIruns,theAbortExecutionbutton,shownatleft,appears.Clickthisbutton
tostoptheVIimmediatelyifthereisnootherwaytostoptheVI.Ifmorethanonerunning
top-levelVIusestheVI,thebuttonisdimmed. Note:AvoidusingtheAbortExecutionbuttontostopaVI.EitherlettheVIcompleteitsdata
owordesignamethodtostoptheVIprogrammatically.Bydoingso,theVIisataknown
state.Forexample,placeabuttononthefrontpanelthatstopstheVIwhenyouclickit.
ClickthePausebutton,shownatleft,topausearunningVI.WhenyouclickthePause
button,LabVIEWhighlightsontheblockdiagramthelocationwhereyoupausedexecution,
andthePausebuttonappearsred.ClickthebuttonagaintocontinuerunningtheVI.
2.9 Execution
InadditiontotheToolbarbuttonsabovethefollowingKeyboardShortcutsareavailable
whendealingwithExecution:
Tutorial:AnIntroductiontoLabVIEW
18
StartusingLabVIEW 2.10
TheObjectsshort-cutmenu
Themostoften-usedmenuistheobjectshortcutmenu.AllLabVIEWobjectsandempty
spaceonthefrontpanelandblockdiagramhaveassociatedshortcutmenus.Usethe
shortcutmenuitemstochangethelookorbehavioroffrontpanelandblockdiagram
objects.Toaccesstheshortcutmenu,right-clicktheobject,frontpanel,orblockdiagram.
TheNumericcontrolhasthefollowingshort-cut/right-clickmenu:
Theshort-cutmenuwillbedifferentforthedifferentcontrolsorobjects.
Tutorial:AnIntroductiontoLabVIEW
19
2.11
StartusingLabVIEW DataflowProgramming
LabVIEWfollowsadataflowmodelforrunningVIs.Ablockdiagramnodeexecuteswhenall
itsinputsareavailable.Whenanodecompletesexecution,itsuppliesdatatoitsoutput
terminalsandpassestheoutputdatatothenextnodeinthedataflowpath.
VisualBasic,C++/C#,Java,andmostothertext-basedprogramminglanguagesfollowa
controlflowmodelofprogramexecution.Incontrolflow,thesequentialorderofprogram
elementsdeterminestheexecutionorderofaprogram.
Example:DataflowProgramming
TheExampleshowsablockdiagramthataddstwonumbersandthensubtracts50.00from
theresultoftheaddition.Inthiscase,theblockdiagramexecutesfromlefttoright,not
becausetheobjectsareplacedinthatorder,butbecausetheSubtractfunctioncannot
executeuntiltheAddfunctionfinishesexecutingandpassesthedatatotheSubtract
function.Rememberthatanodeexecutesonlywhendataareavailableatallofitsinput
terminals,anditsuppliesdatatoitsoutputterminalsonlywhenitfinishesexecution.
Example:DataflowProgramming
Inthisexample,considerwhichcodesegmentwouldexecutefirst-theAdd,Random
Number,orDividefunction.YoucannotknowbecauseinputstotheAddandDivide
functionsareavailableatthesametime,andtheRandomNumberfunctionhasnoinputs.In
asituationwhereonecodesegmentmustexecutebeforeanotherandnodatadependency
Tutorial:AnIntroductiontoLabVIEW
20
StartusingLabVIEW existsbetweenthefunctions,useotherprogrammingmethods,suchaserrorclusters,to
forcetheorderofexecution.
2.12
Help
TheContextHelpwindow(Ctrl+H)displaysbasicinformationaboutLabVIEWobjects
whenyoumovethecursorovereachobject.TheContextHelpwindowisvisiblebydefault.
TotoggledisplayoftheContextHelpwindow,selectHelp-ShowContextHelp,presstheCtrlHkeys,orclicktheShowContextHelpWindowbuttononthetoolbar.
Whenyoumovethecursoroverfrontpanelandblockdiagramobjects,theContextHelp
windowdisplaystheiconforsubVIs,functions,constants,controls,andindicators,with
wiresattachedtoeachterminal.Whenyoumovethecursoroverdialogboxoptions,the
ContextHelpwindowdisplaysdescriptionsofthoseoptions.Inthewindow,required
connectionsarebold,recommendedconnectionsareplaintext,andoptionalconnections
aredimmedordonotappear.TheFigurebelowshowsanexampleoftheContextHelp
window.
Exercises
Exercise:CreateyourfirstLabVIEWapplication(VI)
CreateasimpleLabVIEWapplication(VI)withaFrontPanelwithsomeControlsand
Indicators.CreatethelogicbyconnectingtheTerminalsontheBlockDiagram
TheFrontPanelcouldlooksomethinglikethis:
Tutorial:AnIntroductiontoLabVIEW
21
StartusingLabVIEW TheBlockDiagramcouldlooksomethinglikethis:
StarttheprogramwiththeRunbutton. Exercise:CreateasimpleCalculator
CreateasimplecalculatorthatAddandSubtract2numberslikethis:
Tutorial:AnIntroductiontoLabVIEW
22
StartusingLabVIEW StarttheprogramwiththeRunbutton. Exercise:WriteDatatoFile
CreateaVIthatwritesdatatoaTextFile.
UseVisorfunctionsfromtheFileI/Opalette
Theprogramcouldlooksomethinglikethis:
Tutorial:AnIntroductiontoLabVIEW
23
StartusingLabVIEW Exercise:ReadDatafromFile
CreateanotherVIthatreadthetextfileyoucreatedinthepreviousVI.
Tutorial:AnIntroductiontoLabVIEW
3 SubVIs
ThischapterexplainsthebasicconceptsofcreatingandusingSubVIsinLabVIEW.
Topics:
•
•
•
CreateNewSubVIfromScratch
CreateSubVIfromexistingcode
UsingSubVIs
WhenyouplaceaVIontheblockdiagram,LabVIEWconsiderstheVItobeasubVI.When
youdouble-clickasubVI,itsfrontpanelandblockdiagramappear,ratherthanadialogbox
inwhichyoucanconfigureoptions.Thefrontpanelincludescontrolsandindicators.The
blockdiagramincludeswires,frontpanelicons,functions,possiblysubVIs,andother
LabVIEWobjects.Theupperrightcornerofthefrontpanelandblockdiagramdisplays.
BelowweseeanexampleofabadBlockDiagram.Thisexampledoesnotmakeuseofthe
SubVIfunctionalityinLabVIEWatall!ThismakestheBlockdiagramhardtoreadand
understand.Thesizeofthediagramisalsotoolarge!TheBlockDiagramshouldalwaysfit
intothescreen.BoththeFrontPanelandtheBlockDiagramshouldfitintoascreen
resolutionof1024x768.
24
25
SubVIs WithuseofSubVIs,theexampleabovecouldturninto,e.g.:
Asyoucansee,muchofthecodeintheMainVIhavebeenreplacedandputintoSubVIs.
Theprogramisnowmorereadable.
Anotherapproachistouseaso-calledStateMachineprinciple(moreaboutthisinchapter
11-DesignTechniques).
AvailableKeyboardShortcutswhendealingwithSubVis:
3.1 CreateNewSubVIfromScratch
Tutorial:AnIntroductiontoLabVIEW
26
SubVIs Select“BlankVI”inthe“GettingStarted”windowwhenopeningLabVIEW,orwhenLabVIEW
isalreadyopenedselectFile→NewV”orusetheshort-cutCtrl+N.
3.1.1
InputandOutputSubVIConnectors
MostSubVIswillhaveinputandoutput“connectors”.Thisissimilarwithfunctionsor
methodsinotherprogramminglanguagethathaveinputargumentsandanoutput/result.
Inordertocreateconnectors,Right-clickontheiconintheupperrightcorneroftheVIand
select“ShowConnector”.
YoumayselectdifferentPatterns,i.e.,howmanyinputandoutputconnectorsyouneed.
Tutorial:AnIntroductiontoLabVIEW
27
SubVIs MakesureyouselectaPatternwithenoughconnectorsevenifyoudon’tneedallthe
connectorsatthemoment.IrecommendthatyoustandardizeonthepatternintheFigure
above.
SelecttheWiretoolandclickonthewantedconnector,thenclickontheControlor
IndicatorontheFrontPanelyouwanttoconnecttothisconnector.
Youshouldalwaysfollowtheseconnectorrules:
•
•
•
•
Upperleftconnector:“Reference”In
Upperrightconnector:“Reference”Out
Lowerleftconnector:ErrorInCluster
Lowerrightconnector:ErrorOutCluster
Example:SubVIConnectors
Seeexamplebelowabouttheseconnectorrules:
Tutorial:AnIntroductiontoLabVIEW
28
SubVIs MostcommonVIsthatexitsfollowtheserules,seeexamplebelow.
Ifyoufollowtheseconnectorrulesit’smucheasiertocreateacleanandneatcodelikethis:
Bydoingthisit’salsoclearhowtheDataflowsintheprogram.Itshouldalwaysflowfrom
lefttoright.
3.1.2
IconEditor
YoushouldalsocreateasuitableiconforyourSubVI.
InordertoopentheIconEditor,double-clickontheiconintheupperrightcornerofyourVI.
Tutorial:AnIntroductiontoLabVIEW
29
SubVIs BelowweseeablockdiagramwithSubVIsiconappearancecreatedwiththeIconEditor.
3.2 CreateSubVIfromexistingcode
Ifyoufindoutthatyoucodeisgettingmessy,youcouldconsiderputsomecodeintoa
SubVI.
Theprocedureisasfollows:
1. SelectthepartofyourcodeyouwanttoturnintoaSubVI
2. FromtheEditmenu,select“CreateSubVI”
Tutorial:AnIntroductiontoLabVIEW
30
SubVIs 3. LabVIEWwillautomaticallycreateaSubVIfortheselectedcode.
4. Cleanupautomaticallycreatedwires,etc.
5. CreateasuitableiconforyourSubVI
Althoughthisisquiteeasytodothis,Idonotrecommendthatyouusethisfunctionalityto
much.ThisisbecauseyoushouldcreateanduseSubVIsfromthefirstmomentyoustart
creatingyourapplicationandnotafterwardswhenyoufindoutthatyouhavebeencreating
amessycode.
SoyoushouldstructureanddesignyourcodewiththeuseofSubVIsfromthebeginning!
3.3 UsingSubVIs
BelowweseeanexampleofhowtouseSubVIsinaprogram(TopVIorSubVIs):
YoumayopenaSubVIfromtheFilemenu,selectaSubVIfromtheFunctionspaletteoruse
draganddropindifferentways,e.g.,youmaydragaVIfromtheFileExplorerinWindows
directlyintoanexistingVIyouhavealreadyopenedinLabVIEW
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31
SubVIs Exercises
Exercise:ConvertCtoFVI
CreateaSubVIthatconvertaTemperatureinCelsiustoaTemperatureinFahrenheit
1.
2.
3.
4.
CreatetheSubVI
CreatetheFrontPanelandtheBlockDiagramasshownabove
CreatenecessaryConnectors
Createasuitableicon,e.g.:
5. UsetheSubVIinanotherVI
6. Runtheprogramtoseeifitworks
7. ExpandtheprogramsoyoucanselectifyouwanttoconvertfromCelsiusto
FahrenheitorfromFahrenheittoCelsius
Exercise:ConvertexistingcodeintoaSubVI
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32
SubVIs ConvertapartofyourapplicationintoaSubVIbyusingtheCreateSubVIfunctionin
LabVIEW.
Tutorial:AnIntroductiontoLabVIEW
4 CustomizeLabVIEW
LabVIEWhaslotsofpossibilitiesforcustomizingtheappearanceandtheuseoftheLabVIEW
environment.Select“Options…”fromtheToolsmenu.
Thedefaultsettingsisnotnecessarythebest,herearesomerecommendationsforsetting
uptheLabVIEWenvironment.
Category:BlockDiagram
33
34
CustomizeLabVIEW •
•
Disable“Enableautowiring”option.ThispreventsLabVIEWfromautomatically
connectingadjacentblocks.Althoughitseemsusefultohaveautowiringenables,it
ismyexperiencethattheautowiringisalittleannoyingsinceittendstodrawwires
betweenblockswhenyoudonotwantanywire.
Disable“Placefrontpanelelementsasicons”option.ThiscausesLabVIEWtouse
smallterminaliconsontheblockdiagram.Ifyou,instead,activatethisoption,the
terminaliconsarelarger,withamimicoftheelementasitappearsatthefront
panel. Category:Controls/FunctionsPalettes
•
IntheFormatlist: select“Category(IconsandText)”
Category:AlignmentGrid
•
Turnoff“ShowFrontPanelGrid”and“ShowBlockDiagramGrid”
Exercises
Exercise:CustomizeLabVIEW
Trythedifferentsettingsexplainedinthischapter.Turnthemonandoffandwatchthe
different.
Tutorial:AnIntroductiontoLabVIEW
5 LoopsandStructures
ThischapterexplainsthebasicconceptsofLoopsandStructuresinLabVIEW.
Thetopicsareasfollows:
•
•
•
•
•
ForLoop
WhileLoop
CaseStructure
SequenceStructure
EventStructure
ThedifferentLoopsandStructuresavailablearelocatedinthe“Structures”subpalettein
theFunctionspaletteontheBlockDiagram.
5.1 Loops
Themostimportantloopsare:
•
•
ForLoop
WhileLoop
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36
LoopsandStructures Theseloopswillbeexplainedindetailbelow.
5.1.1
ForLoop
AForLoopexecutesasubdiagramasetnumberoftimes.TheFigurebelowshowsanempty
ForLoopinLabVIEW.
AForloopexecutesitssubdiagramntimes,wherenisthevaluewiredtothecount( )
terminal.Theiteration( )terminalprovidesthecurrentloopiterationcount,whichranges
from0ton-1.
AfteryoucreateaForLoop,youcanuseshiftregisterstopassvaluesfromoneiterationto
thenext.IfyouwireanarraytoaForLoop,youcanreadandprocesseveryelementinthat
arraybyenablingauto-indexing.Youalsocanenableauto-indexingbyconfiguringaFor
Looptoreturnanarrayofeveryvaluegeneratedbytheloop.
YoucanaddaconditionalterminaltoconfigureaForLooptostopwhenaBoolean
conditionoranerroroccurs.AForLoopwithaconditionalterminalexecutesuntilthe
conditionoccursoruntilalliterationscomplete,whicheverhappensfirst.Toadda
conditionalterminaltoaForLoop,right-clicktheForLoopborderandselectConditional
Terminalfromtheshortcutmenu.Youmustwiretheconditionalterminalandeitherwire
thecountterminalorauto-indexaninputarrayforthelooptoexecuteandfortheVItorun.
ToconvertaForLooptoaWhileLoop,right-clicktheForLoopandselectReplacewithWhile
Loopfromtheshortcutmenu.
Example:ForLoop
ThefollowingexampleusesaForLoopinordertocreateanarraywith10elementsandfillit
withrandomnumbers.
Tutorial:AnIntroductiontoLabVIEW
37
LoopsandStructures 5.1.2
WhileLoop
AWhilelooprepeatsthesubdiagraminsideituntiltheconditionalterminal,aninput
terminal,receivesaparticularBooleanvalue.TheBooleanvaluedependsonthe
continuationbehavioroftheWhileLoop.Right-clicktheconditionalterminalandselectStop
ifTrueorContinueifTruefromtheshortcutmenu.Youalsocanwireanerrorclustertothe
conditionalterminal,right-clicktheterminal,andselectStoponErrororContinuewhile
Errorfromtheshortcutmenu.TheWhileLoopalwaysexecutesatleastonce.
BelowweseeanemptyWhileloop:
AfteryoucreateaWhileLoop,youcanuseshiftregisterstopassvaluesfromoneiteration
tothenext.IfyouwireanarraytoaWhileLoop,youcanreadandprocesseveryelementin
thatarraybyenablingauto-indexing.
InordertoconvertaWhileLoopintoaForLoop,right-clicktheWhileLoopandselect
“ReplacewithForLoop”fromtheshortcutmenu.ToconvertaWhileLoopintoaTimed
Loop,right-clicktheWhileLoopandselect“ReplacewithTimedLoop”fromtheshortcut
menu.
Example:WhileLoop
Tutorial:AnIntroductiontoLabVIEW
38
LoopsandStructures Thisexamplerununtileithertheuserclicksthestopbuttonornumberofiterationsis
greaterthan10.
5.2 Structures
5.2.1
CaseStructure
TheCaseStructurehasoneormoresubdiagrams,orcases,exactlyoneofwhichexecutes
whenthestructureexecutes.Thevaluewiredtotheselectorterminaldetermineswhich
casetoexecuteandcanbeBoolean,string,integer,orenumeratedtype.Youmayright-click
thestructurebordertoaddordeletecases.UsetheLabelingtooltoentervalue(s)inthe
caseselectorlabelandconfigurethevalue(s)handledbyeachcase.
BelowweseeanemptyCasestructure:
BelowweseeanexampleofaCasestructurewith2cases,a“True”caseanda“False”case.
DependingoftheBooleaninputvalue,theNumeric1andNumeric2iseitherAddedor
Subtracted.
Tutorial:AnIntroductiontoLabVIEW
39
LoopsandStructures 5.2.2
SequenceStructure
ASequencestructureConsistsofoneormoresubdiagrams,orframes,thatexecute
sequentially.Right-clickthestructurebordertoaddanddeleteframesortocreatesequence
localstopassdatabetweenframes.UsetheStackedSequencestructuretoensureasub
diagramexecutesbeforeorafteranothersubdiagram.
BelowweseeanemptySequencestructure.
Tutorial:AnIntroductiontoLabVIEW
40
LoopsandStructures Belowweseeanexamplewhereweuse“SequenceLocal”,i.e.,wepassavaluefromone
sequencetothenext
Note!TotakeadvantageoftheinherentparallelisminLabVIEW,avoidoverusingSequence
structures.Sequencestructuresguaranteetheorderofexecution,butprohibitparallel
operations.AnothernegativetousingSequencestructuresisthatyoucannotstopthe
executionpartwaythroughthesequence.
5.2.3
EventStructure
AnEventstructurehasoneormoresubdiagrams,oreventcases,exactlyoneofwhich
executeswhenthestructureexecutes.TheEventstructurewaitsuntilaneventhappens,
thenexecutestheappropriatecasetohandlethatevent.Right-clickthestructureborderto
addneweventcasesandconfigurewhicheventstohandle.WireavaluetotheTimeout
terminalatthetopleftoftheEventstructuretospecifythenumberofmillisecondsthe
Eventstructureshouldwaitforaneventtooccur.Thedefaultis–1,indicatingnevertotime
out.
Belowweseeanexample:
Tutorial:AnIntroductiontoLabVIEW
41
LoopsandStructures Right-clickontheborderinordertoAdd/EditEventCases,seethedialogboxbelow.
Tutorial:AnIntroductiontoLabVIEW
42
LoopsandStructures Exercises
Exercise:ForLoop
CreateaVIwithaForLoop.Createthelogictofindoutifanumberinanarrayisgreater
than10.SeeFrontPanelbelow:
Tutorial:AnIntroductiontoLabVIEW
43
LoopsandStructures Exercise:WhileLoop
CreateaVIwithaWhileLoop.Createthelogictofindoutwhich(thefirst)indexinthearray
thathaveanumbergreaterthan30.SeeFrontPanelbelow:
Exercise:CaseStructure
CreateaVIwithaCaseStructure.
UseaCasestructureinsideaForLooptowritethetext“TheNumberisgreaterthan10”if
valueisgreaterthan10.SeeFrontPanelbelow:
Tutorial:AnIntroductiontoLabVIEW
44
LoopsandStructures Exercise:SequenceStructure
CreateaVIwithaSequenceStructure.SeeFrontPanelbelow:
Exercise:EventStructure
CreateaVIwithanEventStructure.SeeFrontPanelbelow:
Tutorial:AnIntroductiontoLabVIEW
6 Troubleshootingand
Debugging
ThischapterexplainsthebasicconceptsoftroubleshootinganddebugginginLabVIEW.
Topics:
•
•
•
•
•
Howtofinderrors
HighlightExecution
Probes
Breakpoints
Stepinto/over/outdebugging
6.1 Howtofinderrors
IfaVIdoesnotrun,itisabroken,or“nonexecutable”,VI.TheRunbuttonoften
appearsbroken,shownatleft,whenyoucreateoreditaVI.Ifitisstillbrokenwhenyou
finishwiringtheblockdiagram,theVIisbrokenandwillnotrun.Generally,thismeansthata
requiredinputisnotwired,orawireisbroken.
ClickthebrokenRunbuttontodisplaytheErrorlistwindow,whichlistsalltheerrors.
Double-clickanerrordescriptiontodisplaytherelevantblockdiagramorfrontpaneland
highlighttheobjectthatcontainstheerror.
6.2 HighlightExecution
ViewananimationoftheexecutionoftheblockdiagrambyclickingtheHighlight
Executionbutton.Executionhighlightingshowstheflowofdataontheblockdiagramfrom
onenodetoanotherusingbubblesthatmovealongthewires.Note!Executionhighlighting
greatlyreducesthespeedatwhichtheVIruns.
45
46
TroubleshootingandDebugging 6.3 Probes
UsetheProbetooltocheckintermediatevaluesonawireasaVIruns. Whenexecutionpausesatanodebecauseofsingle-steppingorabreakpoint,youalsocan
probethewirethatjustexecutedtoseethevaluethatflowedthroughthatwire.Youalso
cancreateacustomprobetospecifywhichindicatoryouusetoviewtheprobeddata.For
example,ifyouareviewingnumericdata,youcanchoosetoseethatdatainachartwithin
theprobe.Tocreateacustomprobe,right-clickawireandselectCustomProbe-Newfrom
theshortcutmenu.
Tutorial:AnIntroductiontoLabVIEW
47
TroubleshootingandDebugging 6.4 Breakpoints
UsetheBreakpointtooltoplaceabreakpointonaVI,node,orwireontheblock
diagramandpauseexecutionatthatlocation.Whenyousetabreakpointonawire,
executionpausesafterdatapassthroughthewire.Placeabreakpointontheblockdiagram
workspacetopauseexecutionafterallnodesontheblockdiagramexecute.WhenaVI
pausesatabreakpoint,LabVIEWbringstheblockdiagramtothefrontandusesamarquee
tohighlightthenodeorwirethatcontainsthebreakpoint.LabVIEWhighlightsbreakpoints
withredbordersfornodesandblockdiagramsandredbulletsforwires.Whenyoumove
thecursoroveranexistingbreakpoint,theblackareaoftheBreakpointtoolcursorappears
white.UsetheBreakpointtooltoclickanexistingbreakpointtoremoveit.
Youmayalsoright-clickonthewireinordertosetabreakpointoropentheBreakpoint
Manager.
BreakpointManagerisatoolforenable,disableanddeletebreakpoints.
Tutorial:AnIntroductiontoLabVIEW
48
TroubleshootingandDebugging 6.5 Stepinto/over/outdebugging
AvailableKeyboardShortcutswhenDebugging:
Exercises
Exercise:HighlightExecution
Enable“HighlightExecution”inoneofyourprograms,andseehowitworks.
Exercise:Probes
SetSeveralProbesaroundinyourapplicationandwatchhowitworks.UsetheProbewatch
Windowandcheckoutthefunctionalitythistooloffers.
Alsocheckoutthe“CustomProbe”andthe“FindProbe”functionality.
Tutorial:AnIntroductiontoLabVIEW
49
TroubleshootingandDebugging Exercise:Breakpoints
SetsomeBreakpointaroundinyourcodeandcheckouthowitworks.UsetheBreakpoint
Managertool.
Example:
Exercise:Stepinto/over/outdebugging
UsetheStepinto/over/outfunctionalitytogetherwithyourBreakpointsandlearnhowyou
canusethemandseewhatthedifferencebetweenthemis.
Tutorial:AnIntroductiontoLabVIEW
7 WorkingwithData
ThischapterexplainsthebasicconceptsofcreatingandusingSubVisinLabVIEW.
Topics:
•
•
•
Arrays
ArrayFunctions
Cluster
7.1 Arrays
ArraysareverypowerfultouseinLabVIEW.Inallyourapplicationsyouwouldprobablyuse
bothOne-DimensionalArraysandTwo-DimensionalArrays.
7.1.1
Auto-Indexing
LabVIEWusesapowerfulmechanismcalled“Auto-indexing”.
ForExampleyoumayuseaForlooptocreateArraydatalikethis:
OryoumayuseanArraylikethisinordertoautomaticallyspecifynumberofiterations:
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51
WorkingwithData 7.1.2
ArrayFunctions
LabVIEWhaslotsofbuilt-infunctionsformanipulatingarrays.
ThemostusefulArrayfunctionsare:
ArraySize
IndexArray
Tutorial:AnIntroductiontoLabVIEW
52
WorkingwithData DeletefromArray
Search1DArray
InitializeArray
BuildArray
ArraySubset
ArrayConstant
Allthesefunctionsarebasic(butveryuseful)arrayfunctionsyouwillprobablybeusinginall
yourapplicationsandVIs.
Example:Arrayfunctions
InthisexampleweseehowwecanusetheseArrayfunctionsandwhattheydo.
TheresultingFrontPanelisasfollows:
Tutorial:AnIntroductiontoLabVIEW
53
WorkingwithData 7.2 Cluster
Clustersgroupdataelementsofmixedtypes,suchasabundleofwires,asinatelephone
cable,whereeachwireinthecablerepresentsadifferentelementofthecluster.Aclusteris
similartoarecordorastructintext-basedprogramminglanguages.Bundlingseveraldata
elementsintoclusterseliminateswireclutterontheblockdiagramandreducesthenumber
ofconnectorpaneterminalsthatsubVIsneed.Theconnectorpanehas,atmost,28
terminals.Ifafrontpanelcontainsmorethan28controlsandindicatorsthatyouwantto
useprogrammatically,groupsomeofthemintoaclusterandassigntheclustertoaterminal
ontheconnectorpane.Likeanarray,aclusteriseitheracontroloranindicator.Acluster
cannotcontainamixtureofcontrolsandindicators.
Tutorial:AnIntroductiontoLabVIEW
54
WorkingwithData Althoughclusterandarrayelementsarebothordered,youmustunbundleallcluster
elementsatonceratherthanindexoneelementatatime.Youalsocanusethe“Unbundle
ByName”functiontoaccessspecificclusterelements.
ExampleofaClusterinLabVIEW:
7.2.1
ClusterOrder
Youmaysortthedifferentelementsintheclusterbyright-clickontheclusterborderand
select“ReorderControlsinCluster…”
Tutorial:AnIntroductiontoLabVIEW
55
WorkingwithData 7.2.2
ClusterElements
InordertomanipulateandworkwithclusterLabVIEWofferslotsoffunctions,suchasthe
“Bundle”and“Unbundle”functions.
Inordertowritetoaclusterfromthecode,youmayusethe“Bundle”functionorthe
“BundleByName”function.Seeexamplebelow:
Example:Clusters
Tutorial:AnIntroductiontoLabVIEW
56
WorkingwithData Inordertogetaccesstothedifferentelementsinthecluster,youneedto“Unbundle”by
usingthe“Unbundle”functionorthe“UnbundleByName”.Seeexamplebelow:
Exercises
Exercise:Arrays
CreatesomesimpleVIswhereyouusethesearrayfunctionstomanipulatearraydata:
ArraySize
IndexArray
DeletefromArray
Search1DArray
InitializeArray
BuildArray
ArraySubset
Exercise:Arrays
CreateaSubVIthatfindthe“peaks”intheinputarrayregardingtoaninputpeaklevel.
Tutorial:AnIntroductiontoLabVIEW
57
WorkingwithData Exercise:Clusters
CreateaClusterandgetthedifferentvaluesfromthecontrolsintheCluster.SeeFrontPanel
below:
Tutorial:AnIntroductiontoLabVIEW
8 WorkingwithStrings
WorkingandmanipulatingwithstringsisanimportantpartinLabVIEWdevelopment.
OntheFrontpanelwehavethefollowingStringcontrolsandindicatorsavailablefromthe
Controlpalette:
OntheBlockDiagramwehavethefollowingStringfunctionsavailablefromtheFunctions
palette:
SomeofthemostimportantStringfunctionsare:
ConcatenateStrings
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59
WorkingwithStrings
Thisfunctionconcatenatesseveralstringsintoonstring:
SearchandReplaceString
Usethiswhenyouwanttoreplaceorremoveacertaintextinastring.
MatchPattern
Tutorial:AnIntroductiontoLabVIEW
60
WorkingwithStrings
Thisisthemostusefulfunctionwhenitcomestostringmanipulation.
FormatIntoString
Example:
Exercises
HerearesomeexercisesusingsomeoftheStringfunctionsthatareavailableinLabVIEW.
Exercise:SubVI:Removeleadingzerosinstring.vi
CreateaSubVIwhichremovesleadingzerosinastring.CreateaTestVIthatusestheSubVI.
Tutorial:AnIntroductiontoLabVIEW
61
WorkingwithStrings
Exercise:SubVI:Removespacefromendofstring.vi
CreateaSubVIwhichremovesallspacesfromtheendofthestring.CreateaTestVIthat
usestheSubVI.
Exercise:SubVI:Add2String.vi
CreateaSubVIwhichadds2stringsintoone.CreateaTestVIthatusestheSubVI.
Tutorial:AnIntroductiontoLabVIEW
9 ErrorHandling
Thischapterexplainsthebasicconceptsofhandleerrorsinyourcode.
Topics:
•
•
•
FindingErrors
ErrorWiring
ErrorHandling
9.1 FindingError
IfaVIdoesnotrun,itisabroken,or“nonexecutable”,VI.TheRunbuttonoftenappears
broken,shownatleft,whenyoucreateoreditaVI.Ifitisstillbrokenwhenyoufinishwiring
theblockdiagram,theVIisbrokenandwillnotrun.Generally,thismeansthatarequired
inputisnotwired,orawireisbroken.ClickthebrokenRunbuttontodisplaytheErrorlist
window,whichlistsalltheerrors.Double-clickanerrordescriptiontodisplaytherelevant
blockdiagramorfrontpanelandhighlighttheobjectthatcontainstheerror.
9.2 ErrorWiring
Errorhandlingisimportantinallprogramminglanguages.LabVIEWhaspowerfulmechanism
forhandlingerrorsanderrorwiring.
YoushouldalwayswiretheErrorclusterbetweenallSubVIs,nodes,etc.thatsupportthis,
seeexamplebelow.
TheErrorclusterislocatedintheControlspalettehere:
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63
ErrorHandling TheErrorCluster:
TheErrorclustercontainsofthefollowingparts:
•
•
•
Status–True/False.False:NoError,True:Error
Code–ErrorCode
Source–TextualErrormessage
9.3 ErrorHandlinginSubVIs
WhencreatingSubVIsyoushouldalwayscreateanErrorInandanErrorOut.IntheSubVI
codeyoushouldalsouseaCasestructureandwiretheErrorinclustertotheCaseSelector
asshownbelow. Tutorial:AnIntroductiontoLabVIEW
64
ErrorHandling 9.4 ErrorHandling
LabVIEWhasseveralusefulSubVIs,etc.forErrorHandling:
Tutorial:AnIntroductiontoLabVIEW
65
ErrorHandling Theseare:
Ingeneralyoushouldalwaysshowtheerrortotheuser.SeeLabVIEWHelpformoredetails
ofhowtousetheseSubVIs.
Exercises
Exercise:ErrorHandling
CheckoutthedifferentErrorVisinLabVIEW.UsetheminsomeofyourpreviousVis.
Tutorial:AnIntroductiontoLabVIEW
10 WorkingwithProjects
ThischapterexplainsthebasicconceptsoftheprojectExplorerinLabVIEW.
Topics:
•
•
•
ProjectExplorer
Building.exe(executable)applications
Deployment:CreateanInstaller
10.1
ProjectExplorer
ItisnotnecessarytousetheProjectExplorerwhendevelopingyourLabVIEWcode,butitis
aneasywaytostructureyourcode,especiallyforlargerprojects.
TheprojectExplorerisnecessarywhenyouwanttodeployyourcodeinto,e.g.,an
executable(.exe)application,buildasetup,etc.
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67
WorkingwithProjects
TheProjectExplorerisalsoveryusefulwhenyouintegrateasourcecontroltool,suchas
TeamFoundationServer,VisualSourceSafe,etc.Thenyoumayeasilycheckfilesinandout
ofthesourcecodesystem. InordertocreateanewProjectinLabVIEW,simplyselect“EmptyProject”fromtheGetting
StartedwindowwhenyouopenLabVIEW.
10.2
Deployment
Whenyourapplicationisfinished,youmaywanttodistributeordeployyourapplicationand
shareitwithothers.
TheProjectExplorergivesyouseveralchoiceswhenitcomestodistributeanddeployyour
application.Someoftheoptionsare:
•
•
•
Createanexecutableapplication(.exe)–thismeansthatthetargetdoesn’tneedto
haveLabVIEWinstalledontheircomputer.AllthetargetneedisLabVIEWRun-Rime,
whichisasmallinstallationpackage.
Youmaycreateyourowninstaller,soallthetargetneedistorunasetup.exein
ordertouseyourapplication
OtherpossibilitiesistocreateaWebServiceoraSharedLibrary(DLL)ofyour
application
Tutorial:AnIntroductiontoLabVIEW
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WorkingwithProjects
AlltheseoptionsareavailablefromtheProjectExplorer,justright-clickonyour“Build
Specifications”node.
Wewillgothroughhowwecreateanexecutableapplication.ClickBuild
Specifications→New→Application(EXE).
InthePropertieswindowfillinyournameoftheapplication.
Tutorial:AnIntroductiontoLabVIEW
69
WorkingwithProjects
MakesureyouselectaStartupVI.
Therearelotsofpropertiesandsettingyoumayuseinordertocreateyourapplication,go
throughalltheCategoriesinthePropertieswindow.
Whenyouhavefinishedallthesteps,justselect“Build”inordertocreateyourapplication.
Whenyoumakechangesinyourapplication,itiseasytorebuildyourapplication:
Exercises
Exercise:ProjectExplorer
CreateanewProjectandputonofyourexistingapplicationintotheproject
Tutorial:AnIntroductiontoLabVIEW
70
Exercise:Deployment
Createanexecutableapplication
Tutorial:AnIntroductiontoLabVIEW
WorkingwithProjects
11 DesignTechniques
Thischapterexplainssomeusefultechniquestousewhencreatingyourapplication.
Topics:
•
•
•
•
•
ForcetheProgramFlowusinganErrorcluster
ShiftRegister
StateMachine
MultipleLoops
Templates
11.1
ForceProgramFlow
Asmentionedearlier,LabVIEWfollowsadataflowmodelforrunningVIs.Ablockdiagram
nodeexecuteswhenallitsinputsareavailable.Whenanodecompletesexecution,it
suppliesdatatoitsoutputterminalsandpassestheoutputdatatothenextnodeinthe
dataflowpath.
IntheexamplebelowwecannotbesurethattheDAQmxWrite.viexecutesbeforethe
DAQmxStopTask.viexecutes.LabVIEWwillinthiscaserandomlyexecuteoneofthesefirst.
IftheStopVIhappenstoexecutefirstthentheWriteVIwillfailedbecausetaskhasbeen
stopped.
IntheexamplebelowwewiretheErrorclusterthroughalltheVIs,andtherewillbeno
doubtthattheWriteVIwillexecutebeforetheStopVI.
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72
DesignTechniques Thisapproachwillalsotakecareoftheerrorhandlinginyourprogram,whichisvery
importantinreal-worldapplications.
11.2
ShiftRegister
UseshiftregistersonForLoopsandWhileLoopstotransfervaluesfromoneloopiteration
tothenext.Shiftregistersaresimilartostaticvariablesintext-basedprogramming
languages.Ashiftregisterappearsasapairofterminals,directlyoppositeeachotheronthe
verticalsidesoftheloopborder.Therightterminalcontainsanuparrowandstoresdataon
thecompletionofaniteration.LabVIEWtransfersthedataconnectedtotherightsideofthe
registertothenextiteration.Createashiftregisterbyright-clickingtheleftorrightborder
ofaloopandselectingAddShiftRegisterfromtheshortcutmenu.
Ashiftregistertransfersanydatatypeandautomaticallychangestothedatatypeofthe
firstobjectwiredtotheshiftregister.Thedatayouwiretotheterminalsofeachshift
registermustbethesametype.
Toinitializeashiftregister,wireanyvaluefromoutsidethelooptotheleftterminal.Ifyou
donotinitializetheshiftregister,theloopusesthevaluewrittentotheshiftregisterwhen
thelooplastexecutedorthedefaultvalueforthedatatypeiftheloophasneverexecuted.
UsealoopwithanuninitializedshiftregistertorunaVIrepeatedlysothateachtimetheVI
runs,theinitialoutputoftheshiftregisteristhelastvaluefromthepreviousexecution.Use
anuninitializedshiftregistertopreservestateinformationbetweensubsequentexecutions
ofaVI.Aftertheloopexecutes,thelastvaluestoredintheshiftregisterremainsattheright
terminal.Ifyouwiretherightterminaloutsidetheloop,thewiretransfersthelastvalue
storedintheshiftregister.Youcanaddmorethanoneshiftregistertoaloop.Ifyouhave
multipleoperationswithinaloop,usemultipleshiftregisterstostorethedatavaluesfrom
thosedifferentprocessesinthestructure.
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DesignTechniques 11.3
StateProgrammingArchitecture
CreatingVIsusingtheStateMachineapproachisveryusefulwhencreating(large)
applications.
Ingeneral,astatemachineisamodelofbehaviorcomposedofafinitenumberofstates,
transitionsbetweenthosestates,andactions.Itissimilartoa"flowgraph"wherewecan
inspectthewayinwhichthelogicrunswhencertainconditionsaremet.
Sometimes,youmaywanttochangetheorderofthesequence,repeatoneiteminthe
sequencemoreoftenthantheotheritems,stopasequenceimmediately,orhaveitemsin
thesequencethatmayexecuteonlywhencertainconditionsaremet.Althoughyour
programmaynothaveanysuchrequirements,thereisalwaysthepossibilitythatthe
programmustbemodifiedinthefuture.Therefore,astateprogrammingarchitectureisa
goodchoice,evenifasequentialprogrammingstructureissufficient.Thefollowinglist
describesmorecomplexprogrammingrequirementsthatjustifytheuseofastate
programmingarchitectureforanapplication.
Tutorial:AnIntroductiontoLabVIEW
74
•
•
•
DesignTechniques Youneedtochangetheorderofthesequence
Youmustrepeataniteminthesequencemoreoftenthanotheritems
Youwantsomeitemsinthesequencetoexecuteonlywhencertainconditionsare
met
TheStateMachineapproachinLabVIEWusesaCasestructureinsideaWhilelooptohandle
thedifferentstatesintheprogram,andthetransitionsbetweenthem.TheShiftRegisteris
usedtosavedatafromandbetweenthedifferentstates.
BelowweseeexamplesofastatemachineprincipleimplementedinLabVIEW.
SimpleStateMachineprinciple
StateMachinewithmultipletransitionsdependingontheState:
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DesignTechniques MoreadvancedStateMachineusingShiftRegisters:
11.4 MultipleLoops/Parallel
programming
Often,youneedtoprogrammultipletaskssothattheyexecuteatthesametime.In
LabVIEWtaskscanruninparalleliftheydonothaveadatadependencybetweenthem,and
Tutorial:AnIntroductiontoLabVIEW
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DesignTechniques iftheyarenotusingthesamesharedresource.Anexampleofasharedresourceisafile,or
aninstrument.
UsingmultipleWhileloopsissometimesusefulinapplicationsthatneedtohandleUser
interactionsinparallelwith,e.g.,DAQoperations,etc.
Belowweseeanexampleofhowthisstructurecouldlooklike.Theupperloopcouldhandle
interactionwiththeuser,whilethelowerloopcouldhandleDAQoperations,suchas
readingandwritingtosomeI/Oequipments.
Tutorial:AnIntroductiontoLabVIEW
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DesignTechniques Inordertopassdatabetweentheloops,youmaye.g.uselocalvariables.Theloopmayhave
differenttimecycles.TheI/OmayrequirefastercyclesthantheUserinteractionloop.
11.5
Templates
YoushouldcreateyourowntemplatesforsuchVIyouusealot.Itiseasytocreateyourown
templatesforscratch,justcreateaVIasyounormallydoandthensaveitasatemplatewith
theending“.vit”.YoumayalsoconvertaVIyoualreadymadejustbychangingtheextension
to“.vit”.
YoushouldcopyyourtemplatestotheLabVIEWtemplatefolderwhichisdefaultlocatedin
“C:\ProgramFiles\NationalInstruments\LabVIEWX.X\Templates\”.
TheTemplateswillthenbeavailablefromtheGettingStartedWindoworFile→New…in
LabVIEW.
ImaycaseIhavecreatedasubfoldercalled“MyTemplates”whereIplaceallmytemplates.
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DesignTechniques Exercises
Herearesomeexercisesaboutshift-registers,StateMachinesandparallelprogramming.
Exercise:Shift-register
CreateaVI(seeexamplebelow)whereyouhavethefollowingstates:
•
•
•
•
Initialize
Write
Read
Close
IntheVIyouwilluseashift-registerasatemporarystorage.IntheWritestateyouWrite
Datatothestorage(shift-register)whileyouintheReadstatewillreadtheDatafromthe
Storage.
SeeExamplebelow: Tutorial:AnIntroductiontoLabVIEW
79
DesignTechniques WriteaTestprogramthattesttheSubVI,e.g., Thisexampleshowshowyoucanuseashift-registerasatemporarystorage,whichisvery
usefulinmanysituations.
Exercise:StateMachine
UsetheStateMachineprincipleononeofyourpreviousexercises.
Exercise:ParallelProgramming
CreateaVIthatconsistsof2parallelloops.Uselocalvariablesandothermechanismsin
ordertosharedatabetweenthe2loops.
Exercise:Templates
StripsomeofyourspreviousVisandsavethemasreusableTemplates.
Tutorial:AnIntroductiontoLabVIEW
12 UserInterface
Thischapterexplainsthebasicconceptsofcreatinguser-friendlyGraphicalUserInterfaces
(GUI)inLabVIEW.
Topics:
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Decorations
TabControl
Splitter
SubPanel
Etc.
BelowweseeaFrontPanel(GUI)witha“poor”design.
Theinformation(ControlsandIndicators)ontheFrontPanelisnotstructured.Youshould
groupelementsthatnaturallybelongtogetherandusedifferentcolorswithcare.
WhencreatingGraphicalUserInterfaces(GUI)youshouldusethecontrolsfromtheSystem
paletteandnotfromtheModernorClassicpalettes.ModernControlsmaybeusedinSub
ViswithnovisibleUserInterface(fortheuser).
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UserInterface TheappearanceofthecontrolsintheSystempaletteisstandardMSWindowslookand
feelingandthislookisfamiliarformostusers.Thesecontrolsalsochangeappearancedueto
changesintheappearanceintheoperationsystem.
12.1
VIProperties
InordertomaketheappearanceoftheWindowthathostsyourapplication,youshould
alwaysmakesomechangesinthe“VIProperties”.
Youfindthe“VIProperties”byright-clickontheiconintheupperrightcornerofyourVI.
Tutorial:AnIntroductiontoLabVIEW
82
UserInterface Thefirstthingyoushouldchangeisthe“Windowtitle”.Hereyoumaytypeappropriate
nameofyourapplicationorSubVI.
Thenextyoushoulddoistothe“Customize”buttoninordertocustomizetheWindow
appearance.
BelowweseeanapplicationwithasimpleandneatUserInterfaceandwithaCustomized
Windowsappearance.
Tutorial:AnIntroductiontoLabVIEW
83
UserInterface BelowweseeaprofessionalapplicationcreatedinLabVIEWthatimplementcommonGUI
objectssuchasaToolbar,aTreeview,aListview,etc..
Tutorial:AnIntroductiontoLabVIEW
84
UserInterface Exercises
Exercise:UserInterface
CreateaDialogBoxwhereyouusesomeoftheControlsfromtheSystempalette.Makethe
necessarysettingsinVIPropertiesinordertohidemenus,buttons,createaTitle,etc.
CreateaTestVIfromwhereyouopenthisDialogBox,entersomedataintheDialogBox,
andthenretrievethesedatainthecallingVI.
Example:
Tutorial:AnIntroductiontoLabVIEW
13 PlottingData
ThischapterexplainsthebasicconceptswhenplottingdatainLabVIEW.
LabVIEWofferspowerfulfunctionalityforplottingdata.IntheGraphpalettewehavelotsof
usefulcontrolsforplottingandvisualizationofdata.
Themostusefulare:
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WaveformChart
WaveformGraph
XYGraph
Example:
Thissimpleexamplecreatesagraphwithsomerandomvalues.
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PlottingData
Theexamplebelowshowthebasicdifferencebetweena“Chart”anda“Graph”.
Tutorial:AnIntroductiontoLabVIEW
87
PlottingData
Youusethe“Graph”ifyouwanttoplotasetofdata,e.g.,anarraywithdata,plotdatafrom
afile,etc.Usethe“Chart”ifyouwanttoplotonedatapointatatime,e.g.,insidealoop,
etc.
13.1
Customizing
ThedifferentChartcomponentsinLabVIEWofferagreatdealofcustomizing. Youmayclickonthe“PlotLegend”inordertosetcolors,differentline
styles,etc.
Ifyouright-clickontheGraph/Chart,youmaysetpropertiessuchasauto-scaling,etc.
Tutorial:AnIntroductiontoLabVIEW
88
PlottingData
IfyouselectProperties,yougetthefollowingdialog:
Youmayalsoselectwhichitemsthatshouldbevisibleornot.
Tutorial:AnIntroductiontoLabVIEW
89
PlottingData
The“GraphPalette”letsyouzoominandoutontheGraph,etc.
Exercises
Exercise:Graph
CreateaVIthatreadsdatafromafileandplotthedatainaGraphcomponent.
Exercise:Chart
CreateaVIwhereyouuseDataBindinginordertoretrievedatafromanOPCdemo.
DataBindingissetintheProperties→DataBindingtab:
Tutorial:AnIntroductiontoLabVIEW
90
PlottingData
Exercise:Customizing
CustomizetheGraphandtheChartintheexamplesaboveinordertosetcolors,line
thickness,etc.
Tutorial:AnIntroductiontoLabVIEW
14 Tips&Tricks
ThischaptergivesyousomeusefulTips&TricksregardingLabVIEW.
14.1 10functionsyouneedtoknow
about
Thesearethe10mostusefulfunctionsinLabVIEW,soyoucouldalreadynowlearnhowto
usethemandwheretofindthem!
BuildArray
ThisexampleusingtheBuildArrayfunctioninsideaForloopinorderbuildanarraywith10
elements.
IndexArray
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Tips&Tricks Itisalwaysusefultofindaspecificvalueinanarray:
TheIndexArrayisextendible,soyoucandragitouttofindmorethanoneelements: ArraySize
Findthesizeofanarbitraryarray:
Select
Tutorial:AnIntroductiontoLabVIEW
93
Tips&Tricks Dependingontheinputdata,gototheAlarmcaseortheWriteDatacase.
ConcatenateStrings
Thisfunctionconcatenateseveralstringsintoonstring:
SearchandReplaceString
Tutorial:AnIntroductiontoLabVIEW
94
Tips&Tricks Usethiswhenyouwanttoreplaceorremoveacertaintextinastring.
MatchPattern
Thisisthemostusefulfunctionwhenitcomestostringmanipulation.
FormatIntoString
Tutorial:AnIntroductiontoLabVIEW
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Tips&Tricks Example:
Fract/ExpStringtoNumber
Thisfunctionconvertsastringintoanumber:
Example:NumberToFractionalString
Example:
Tutorial:AnIntroductiontoLabVIEW
96
Tips&Tricks 14.2
The10mostusefulShort-cuts
Thesearethe10mostusefulshort-cutsinLabVIEW,soyoucouldalreadynowlearnhowto
usethem!
Short-Cut
Ctrl+B
Ctrl+.
Ctrl+E
Tab
Ctrl+Mouse
wheel
Ctrl+H
Ctrl+Mouse
Double-clickona
SubVI
Ctrl+Arrows
(→←←↓)
Ctrl+W
Double-clickona
wire
Description
DeletesallbrokenwiresinaVI
StopstheRunningVI
TogglebetweentheFrontPanelandBlockDiagram
CyclesthroughthemostcommonTools(AutomaticToolSelection
shouldbedisabled!)
ScrollsthroughsubdiagramsinCase,EventorSequencestructures
DisplaystheContextHelpwindow
OpenstheBlockDiagramdirectly
Movefaster.YoufirsthavetoselectaSubVI,aFunction,Object,etc
ClosetheSubVI
Selectstheholewire
Tutorial:AnIntroductiontoLabVIEW
15 ExampleApplication
Inthisexamplewewillgothroughanexampleapplication.Theapplicationusesmostofthe
LabVIEWfeaturesyouhavelearnedinthisTutorial.
Theapplicationiscalled“Glossary”.Itisasimpleapplicationthatlearnskid’swordsin
English.Sincetheapplicationisforkids,theuserinterfaceiscreatewitha“childish”look
andfeel.
Thisisanexampleofhowtocreateauser-friendlyapplicationinLabVIEWthatusesmostof
thefunctionalityinLabVIEW,suchasState-machineprinciples,readingandwritingtofiles,
dialogboxes,graphicsandsoundeffects.Basicfunctionsforstringandarraymanipulation,
andofcoursewhileloops,casestructures,subVIs,etc.TheexamplealsousestheProject
Explorertocollectallthefilesinoneplaceandtocreateanexecutablefileofthesolution.
FinallyitusestheProjectExplorertocreateasetuppackageyoucanusetoinstallthe
applicationeasilyonothercomputers.
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ExampleApplication IcreatedthisapplicationformykidsinthePrimaryschoolwhohadproblemswithlearning
theirhomeworkinEnglish.
UsethecodeasanexampleforcreatingyourownstunningLabVIEWapplications.Thecode
isavailablefordownloadatmyblog:http://home.hit.no/~hansha.
BelowweseetheGlossaryList:
Ifyouclickonthelittlebooksymbolinyourapplication,thiswindowwillpopup:
Clicktissymbolandyoucanenternewwords:
Tutorial:AnIntroductiontoLabVIEW
99
ExampleApplication TheapplicationusestheProjectExplorer:
Tutorial:AnIntroductiontoLabVIEW
100
ExampleApplication Thismakesiteasytokeepanoverviewofallyourfilesinyourproject.Youmayalsousethe
ProjectExplorertocreateanexecutablefileofyourapplication.Inadditionyoumayalso
createaninstallationpackagesoyoucaneasilyinstalltheapplicationonothercomputers.
AspartoftheinstallationtheLabVIEWRun-timeenginewillbeinstalled.
BlockDiagram:
Theapplicationusesthestatemachineprinciple,whichmakesiteasytocreatelarge
applications:
Tutorial:AnIntroductiontoLabVIEW
16 AdditionalExercises
Thischapterlistslotsofadditionalexercisesyoucouldtryoutinordertoimproveyour
LabVIEWskills.
Exercise:vCardReader
CreateanapplicationthatreadsinformationfromavCard.
vCardisafileformatstandardforelectronicbusinesscards.vCardsareoftenattachedtoemailmessages,butcanbeexchangedinotherways,suchasontheWorldWideWeb.They
cancontainnameandaddressinformation,phonenumbers,URLs,logos,photographs,and
evenaudioclips.
Example:
BEGIN:VCARD
VERSION:2.1
N:Gump;Forrest
FN:Forrest Gump
ORG:Bubba Gump Shrimp Co.
TITLE:Shrimp Man
TEL;WORK;VOICE:(111) 555-1212
TEL;HOME;VOICE:(404) 555-1212
ADR;WORK:;;100 Waters Edge;Baytown;LA;30314;United States of America
LABEL;WORK;ENCODING=QUOTED-PRINTABLE:100 Waters Edge=0D=0ABaytown, LA 30314=0D=0AUSA
ADR;HOME:;;42 Plantation St.;Baytown;LA;30314;United States of America
LABEL;HOME;ENCODING=QUOTED-PRINTABLE:42 Plantation St.=0D=0ABaytown, LA 30314=0D=0AUSA
EMAIL;PREF;INTERNET:forrestgump@example.com
REV:20080424T195243Z
END:VCARD
FormoreinformationaboutthevCardformat,seehttp://en.wikipedia.org/wiki/VCard.
Theapplicationshouldlooksomethinglikethis:
WhentheuserclickOpen,thenadialogboxlikethisshouldappear:
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AdditionalExercises Requirements:
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UsetheProjectExplorer
UsetheStateMachineprinciple
UsetheEventStructure
UseSystemControls
SettheappropriatesettingsintheVIProperties.
Createaexecutableapplication(vCard.exe)
Exercise:vCardWrite&Read
Extendtheapplicationinthepreviousexample.Youshouldnowbeabletobothwriteand
readvCardfiles.Theapplicationcouldlooksomethinglikethis:
Tutorial:AnIntroductiontoLabVIEW
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AdditionalExercises WhentheuserclicksNew,thedialogboxinthepreviousexerciseappears.Theusermay
enteranewvCard.IftheuserclicksEdit,adialogboxwiththeselectedcontactshould
appear. Exercise:Read/Writefrom.inifiles
Read/Writefrom.inifiles.UsetheConfigurationFileVIs:
Exercise:ActiveX
CreateasimpleWebBrowserusingActiveXandtheInternetExplorerActiveXcontrol
(MicrosoftWebBrowser)
UsetheActiveXContainerfromtheContainerscontrolpalette:
Tutorial:AnIntroductiontoLabVIEW
104
AdditionalExercises UsetheActiveXfunctionpalette:
Theapplicationcouldlooksomethinglikethis:
Exercise:Themes
Tutorial:AnIntroductiontoLabVIEW
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AdditionalExercises Ine.g.,ASP.NETwehavesomethingcalledThemes.Themesareusedtochangethe
appearanceofyourwholeapplicationregardingtocolor,font,pictures,etc.
LabVIEWdonotoffersuchafunctionality,buttrytocreateyourownThemeConfigurator,
soyoucanchangetheappearanceofyourVIinstantly.
HereisanexampleofhowWindowsXPhandlesdifferentThemes:
CreateasimilarThemeConfiguratorsoyoumayeasilychangetheappearanceofyourVis.
Tutorial:AnIntroductiontoLabVIEW
17 What’sNext?
17.1
MyBlog
FormoreinformationaboutLabVIEW,visitmyBlog:http://home.hit.no/~hansha/
LabVIEWBasics:
http://home.hit.no/~hansha/video/labview_basics.php LabVIEWTrainingandResources:
http://home.hit.no/~hansha/?training=labview 17.2
Tutorials
ThisTutorialisapartofaserieswithotherTutorialsIhavemade,suchas:
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•
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•
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IntroductiontoLabVIEW
DataAcquisitioninLabVIEW
ControlandSimulationinLabVIEW
LabVIEWMathScript
LinearAlgebrainLabVIEW
DataloggingandSupervisoryControlinLabVIEW
ModelPredictiveControlinLabVIEW
WirelessDataAcquisitioninLabVIEW
etc.
TheseTrainingKitsareavailablefordownload(.pdffiles,sourcecode,additionalresources,
etc.)frommyblog:http://home.hit.no/~hansha
17.3
AdditionalResources
YoufindlotsofinformationaboutLabVIEWinNationalInstrumentswebsite:
www.ni.com
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17.4
What’sNext? Examples
IntheNIexampleFinder(Help→FindExamples…)youfindlotsofusefulexamplesthatyou
canplaywithoruseasastartwhencreatingyourownapplications. Tutorial:AnIntroductiontoLabVIEW
QuickReference
108
QuickReference
Tutorial:AnIntroductiontoLabVIEW
Hans-PetterHalvorsen,M.Sc.
E-mail:hans.p.halvorsen@hit.no
Blog:http://home.hit.no/~hansha/
UniversityCollegeofSoutheastNorway
www.usn.no