NI官方labview培训教材Lesson+5-8.ppt

1,Lesson5Clusters,TOPICSIntroductiontoClustersClusterFunctionsErrorClusters,2,Clusters,DatastructurethatgroupsdatatogetherDatamaybeofdifferenttypesAnalogoustostructinCorarecordinPascalElementsmustbeeitherallcontrolsorallindicatorsThoughtofaswiresbundledintoacable,3,1.SelectaClustershellfromtheArrayeachnumberrepresentsacolorUsetheseoptionstosetanddisplaycolormappingschemeCursoralsoaddsathirddimension,26,Thewaveformchartisaspecialnumericindicatorthatdisplaysoneormoreplots.Thewaveformcharthasthefollowingthreeupdatemodes:Astripchartshowsrunningdatacontinuouslyscrollingfromlefttorightacrossthechart.Ascopechartshowsoneitemofdata,suchasapulseorwave,scrollingpartwayacrossthechartfromlefttotheright.Asweepworkssimilarlytoascopeexceptitshowstheolddataontherightandthenewdataontheleftseparatedbyaverticalline.WaveformgraphsandXYgraphsdisplaydatafromarrays.Right-clickawaveformchartorgraphoritscomponentstosetattributesofthechartanditsplots.,Summary,27,YoucandisplaymorethanoneplotonagraphusingtheBuildArrayfunctionandtheBundlefunctionforchartsandXYgraphs.Thegraphbecomesamultiplotgraphwhenyouwirethearrayofoutputstotheterminal.Whenyouwiredatatochartsandgraphs,usetheContextHelpwindowtodeterminehowtowirethem.Youcanuseintensitychartsandgraphstoplotthree-dimensionaldata.Thethirddimensionisrepresentedbydifferentcolorscorrespondingtoacolormappingthatyoudefine.Intensitychartsandgraphsarecommonlyusedinconjunctionwithspectrumanalysis,temperaturedisplay,andimageprocessing.,Summary,cont.,28,Lesson7MakingDecisionsinaVI,TOPICSDecisionmakingwiththeSelectfunctionCaseStructuresFormulaNodes,29,SimpleDecision:SelectFunction,IfTempScaleisTRUE,passtopinput;iftempscaleisFALSE,passbottominput.IfthedecisiontobemadeismorecomplexthanaSelectfunctioncanexecute,aCaseStructuremaybewhatisrequired.,30,BooleanCaseStructureExample:IfTempScaleisTRUE,executeTruecase;iftempscaleisFALSE,executeFalsecase.,CaseStructures,31,IntheStructuressubpaletteofFunctionspaletteEnclosenodesordragtheminsidethestructureStackedlikeadeckofcards,onlyonecasevisibleatatime,CaseStructures,32,BooleanandNumericCases,Wireallpossibleoutputsofthecasestructure,33,String,Enum,andErrorCases,StringCaseEnumCaseErrorCase,34,IntheStructuressubpaletteImplementcomplicatedequationsVariablescreatedatborderVariablenamesarecasesensitiveEachstatementmustterminatewithasemicolon(;)ContextHelpWindowshowsavailablefunctions,Notesemicolon,FormulaNode,35,DecisionMakingwithFormulaNodes,Twodifferentwaysofusinganif-thenstatementinaFormulaNodeBothstructuresproducethesameresult,36,TheSelectfunctionisusedtochoosebetweentwoinputsdependantonabooleaninput.ACasestructurehastwoormorecases.Onlyonecaseisvisibleatatime,andthestructureexecutesonlyonecaseatatime.IfthecaseselectorterminalisBoolean,thestructurehasaTRUEcaseandaFALSEcase.Iftheselectorterminalisaninteger,string,orenumeratedtypevalue,thestructurecanhaveupto2311cases.Inputsareavailabletoallcases,butcasesdonotneedtouseeachinput.Ifatleastoneoutputtunnelisnotdefined,alloutputtunnelsonthestructureappearaswhitesquares.FormulaNodesareusefulforcomplicatedequationsandforusingexistingtext-basedcode.Asemicolon(;)mustterminateeachstatement.,Summary,37,Lesson8StringsandFileI/O,TOPICSHowtocreatestringcontrolsandindicatorsHowtouseseveralStringfunctionsAboutfileI/OoperationsHowtousethehigh-levelFileI/OVIsHowtousethelow-levelFileI/OVIsHowtoformattextfilesforuseinspreadsheets,38,Astringisasequenceofdisplayableor-characters(ASCII)Manyusesdisplayingmessages,instrumentcontrol,fileI/OStringcontrol/indicatorisintheControlsStringsubpalette,Strings,39,StringDisplayModes,NormaldisplayPassworddisplay,codedisplayHexdisplay,40,ConcatenateStrings,(spaceshere),StringLength,StringFunctions,41,StringFunctions,StringSubset,MatchPattern,42,ConvertingNumericstoStrings:BuildString,43,ConvertingStringstoNumerics:ScanFromString,44,EditFormatString,ScanFromStringFunction,45,FileInputandOutput,FourHierarchyLevels:High-levelFileVIsIntermediateFileVIsandFunctionsAdvancedFileFunctionssubpaletteExpressVIs,46,WritetoSpreadsheetFileReadfromSpreadsheetFileWriteCharacterstoFileReadCharactersfromFileReadLinesfromFile,High-levelFileI/OVIs,47,FileI/OProgrammingModel-Intermediate,Open/Create/ReplaceFile,Readand/orWritetoFile,CloseFile,CheckforErrors,48,WritetoFileExample,Open/Create/ReplaceopenstheexistingfileTEST1.DATandgeneratesrefnumanderrorclusterWriteFilewritesthedataCloseFileclosesthefileSimpleErrorHandlerchecksforerrors,49,ReadingDatafromaFile,Open/Create/ReplaceopensthefileReadFilereadsthespecifiednumberofbytesfromthefileCloseFileclosesthefileSimpleErrorHandlerchecksforerrors,50,FormattingaSpreadsheetString,SpreadsheetsarepopulartoolsfordatahandlingandanalysisTherearemanyformatsforspreadsheetdata.Oneofthemostpopularistab-delimited:ColumnsareseparatedbyatabcharacterRowsareseparatedbyanend-of-linecharacter,Tab,EndofLine,Aspreadsheetyields:,51,CreatingaSpreadsheetFile,CanreplaceFormatIntoStringandWriteFilewithFormatIntoFileinaboveexample,52,WriteLabVIEWMeasurementFile,Includestheopen,write,closeanderrorhandlingfunctionsHandlesformattingthestringwitheitherataborcommadelimiterMergeSignalsfunctionisusedtocombinedataintothedynamicdatatype,53,StringsgroupsequencesofASCIIcharacters.UsethestringcontrolandindicatorlocatedontheControlsString&Pathpalettetosimulatetextentryboxesandlabels.UsetheStringfunctionslocatedontheFunctionsStringpalettetoeditandmanipulatestringsontheblockdiagram.UsetheFormatIntoStringfunctionandtheBuildStringExpressVItoconvertanumerictoastring.UsetheScanFromStringfunctiontoconvertastringtoanumeric.Right-clicktheFormatIntoStringorScanFromStringfunctionandselectEditFormatStringorEditScanString