Labview图形化编程语言中英文对照外文翻译文献文档格式.docx

Labview图形化编程语言中英文对照外文翻译文献文档格式.docx

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AProgrammingEnvironmentforLaboratoryAutomationandMeasurement.

NationalInstrumentsLabVIEWisagraphicalprogramminglanguagethathasitsrootsinautomationcontrolanddataacquisition.Itsgraphicalrepresentation,similartoaprocessflowdiagram,wascreatedtoprovideanintuitiveprogrammingenvironmentforscientistsandengineers.Thelanguagehasmaturedoverthelast20yearstobecomeageneralpurposeprogrammingenvironment.LabVIEWhasseveralkeyfeatureswhichmakeitagoodchoiceinanautomationenvironment.Theseincludesimplenetworkcommunication,turnkeyimplementationofcommoncommunicationprotocols（RS232,GPIB,etc.）,powerfultoolsetsforprocesscontrolanddatafitting,fastandeasyuserinterfaceconstruction,andanefficientcodeexecutionenvironment.Wediscussthemeritsofthelanguageandprovideanexampleapplicationsuitewrittenin-housewhichisusedinintegratingandcontrollingautomationplatforms.

Keywords:

NILabVIEW;

graphicalprogramming;

systemintegration;

instrumentcontrol;

componentbasedarchitecture;

robotics;

automation;

staticscheduling;

dynamicscheduling;

database

Introduction

Cytokineticsisabiopharmaceuticalcompanyfocusedonthediscoveryofsmallmoleculetherapeuticsthattargetthecytoskeleton.Sinceinceptionwehavedevelopedarobusttechnologyinfrastructuretosupportourdrugdiscoveryefforts.Theinfrastructureprovidescapacitytoscreenmillionsofcompoundsperyearintestsrangingfrommultiproteinbiochemicalassaysthatmimicbiologicalfunctiontoautomatedimage-basedcellularassayswithphenotypicreadouts.Therequirementsforprocessingthesenumbersanddiversityofassayshavemandateddeploymentofmultipleintegratedautomationsystems.Forexample,wehaveseveralplatformsforbiochemicalscreening,systemsforlivecellprocessing,automatedmicroscopysystems,andanautomatedcompoundstorageandretrievalsystem.Eachin-houseintegratedsystemisdesignedaroundaroboticarmandcontainsanoptimalsetofplate-processingperipherals（suchaspipettingdevices,platereaders,andcarousels）dependingonitsintendedrangeofuse.Tocreatethemostflexible,highperformance,andcost-effectivesystems,wehavetakentheapproachofbuildingourownsystemsin-house.Thishasgivenustheabilitytointegratethemostappropriatehardwareandsoftwaresolutionsregardlessofwhethertheyarepurchasedfromavendororengineereddenovo,andhencewecanrapidlymodifysystemsasassayrequirementschange.

Tomaximizeplatformconsistencyandmodularity,eachofour10automatedplatformsiscontrolledbyacommon,distributedapplicationsuitethatwedevelopedusingNationalInstruments（NI）LabVIEW.Thisapplicationsuitedescribedindetailbelow,enablesourenduserstocreateandmanagetheirownprocessmodels（assayscripts）inacommonmodelingenvironment,tousetheseprocessmodelsonanyautomationsystemwiththerequireddevices,andallowseasyandrapiddevicereconfiguration.TheplatformissupportedbyacentralOracledatabaseandcanruneitherstaticallyordynamicallyscheduledprocesses.

NILabVIEWBackground

LabVIEW,whichstandsforLaboratoryVirtualInstrumentationEngineeringWorkbenchisagraphicalprogramminglanguagefirstreleasedin1986byNationalInstruments（Austin,TX）.LabVIEWimplementsadataflowparadigminwhichthecodeisnotwritten,butratherdrawnorrepresentedgraphicallysimilartoaflowchartdiagramProgramexecutionfollowsconnectorwireslinkingprocessingnodestogether.Eachfunctionorroutineisstoredasavirtualinstrument（VI）havingthreemaincomponents:

thefrontpanelwhichisessentiallyaformcontaininginputsandcontrolsandcanbedisplayedatruntime,ablockdiagramwherethecodeiseditedandrepresentedgraphically,andaconnectorpanewhichservesasaninterfacetotheVIwhenitisimbeddedasasub-VI.

Thetoppanel（A）showsthefrontpaneloftheVI.Inputdataarepassedthrough“Controls”whichareshowntotheleft.Includedherearenumberinputs,afilepathbox,andageneralerrorpropagationcluster.WhentheVIruns,the“Indicator”outputsontherightofthepanelarepopulatedwithoutputdata.Inthisexample,dataincludenumbers（bothasscalarandarray）,agraph,andtheoutputoftheerrorcluster.Inthebottompanel（B）theblockdiagramfortheVIisshown.Theoutercasestructureexecutesinthe“NoError”case（VIscanmakeinternalerrorsorifcalledasasub-VIthecallermaypropagateanerrorthroughtheconnectorpane）.

Unlikemostprogramminglanguages,LabVIEWcompilescodeasitiscreatedtherebyprovidingimmediatesyntacticandsemanticfeedbackandreducingthetimerequiredfordevelopmentandtesting.2WritingcodeisassimpleasdragginganddroppingfunctionsorVIsfromafunctionspaletteontotheblockdiagramwithinprocessstructures（suchasForLoops,orCaseStructures）andwiringterminals（passinginputvalues,orreferences）.Unittestingissimplifiedbecauseeachfunctionisseparatelyencapsulated;

inputvaluescanbesetdirectlyonthefrontpanelwithouthavingtotestthecontainingmoduleorcreateaseparatetestharness.Thefunctionsthatgeneratedatatakecareofmanagingthestorageforthedata.

NILabVIEWsupportsmultithreadedapplicationdesignandexecutescodeinaninherentlyparallelratherthansequentialmanner;

assoonasafunctionorsub-VIreceivesallofitsrequiredinputs,itcanbeginexecution.InFigure 

1b,allthesub-VIsreceivethearrayinputsimultaneouslyassoonastheForLoopiscomplete,andthustheyexecuteinparallel.Thisisuniquefromatypicaltext-basedenvironmentwherethecontrolflowslinebylinewithinafunction.Whensequentialexecutionisrequired,controlflowcanbeenforcedbyuseofstructuressuchasSequences,Events,orbychainingsub-VIswhereoutputdatafromoneVIispassedtotheinputofthenextVI.

Similartomostprogramminglanguages,LabVIEWsupportsallcommondatatypessuchasintegers,floats,strings,andclusters（structures）andcanreadilyinterfacewithexternallibraries,ActiveXcomponents,and.NETframework.AsshowninFigure 

1b,eachdatatypeisgraphicallyrepresentedbywiresofdifferentcolorsandthickness.LabVIEWalsosupportscommonconfigurationmanagementapplicationssuchasVisualSourceSafemakingmultideveloperprojectsreasonabletomanage.ApplicationsmaybecompiledasexecutablesorasDynamicLinkLibraries（DLLs）thatexecuteusingarun-timeenginesimilartotheJavaRuntimeEnvironment.Thedevelopmentenvironmentprovidesavarietyofdebuggingtoolssuchasbreak-points,trace（trace）,andsingle-step.ApplicationscanbedevelopedusingavarietyofdesignpatternssuchasClient-Server,Consumer-Producer,andState-Machine.TherearealsoUML（UnifiedModelingLanguage）modelingtoolsthatallowautomatedgenerationofcodefromUMLdiagramsandstatediagrams.

Overtheyears,LabVIEWhasmaturedintoageneralpurposeprogramminglanguagewithawideruserbase.

NILabVIEWasaPlatformforAutomationandInstrumentation

OurexperiencecreatingbenchtopinstrumentationandintegratedautomationsystemshasvalidatedourchoiceofLabVIEWasanappropriatetool.LabVIEWenablesrapiddevelopmentoffunctionallyrichapplicationsappropriateforbothbenchtopapplicationsandlargerintegratedsystems.Onmanyoccasionswehavefoundthatprojectrequirementsareinitiallyilldefinedorchangeasnewmeasurementsornewassaysaredeveloped..Thereareseveralkeyfeaturesofthelanguagethatmakeitparticularlyusefulinanautomationenvironmentforcreatingapplicationstocontrolandintegrateinstrumentation,manageprocessflow,andenabledataacquisition.

TurnkeyMeasurementandControlFunction

LabVIEWwasoriginallydevelopedforscientistsandengineers.ThelanguageincludesarichsetofprocesscontrolanddataanalysisfunctionsaswellasCOM,.NET,andsharedDLLsupport.Outofthebox,itprovidesturnkeysolutionstoavarietyofcommunicationprotocolsincludingRS232,GPIB,andTCP/IP.ControlstructuressuchastimedWhileLoopsallowsynchronizedandtimeddataacquisitionfromavarietyofhardwareinterfacessuchasPCI,USB,andPXI.

DataSocketandVIServer

Deploymentofanintegratedsystemwithmultiplecontrolcomputersrequirestheautomationcontrolapplicationtocommunicateremotelywithinstrumentdriversexistingonremotecomputers.LabVIEWsupportsadistributedarchitecturebyvirtueofenablingseamlessnetworkcommunicationthroughtechnologiessuchasVIServerandDSTP（datasocketstransferprotocol）.DSTPisanapplicationlayerprotocolsimilartohttpbasedonTransmissionControlProtocol/InternetProtocol（TCP/IP）.Datasocketsalloweasytransferofdatabetweenremotecomputerswithbasicreadandwritefunctions.ThroughVIservertechnology,functioncallscanbemadetoVIsresidingonremotecomputersasthoughtheyareresidingonthelocalcomputer.BothDatasocketsandVIservercanbeconfiguredtocontrolaccessesprivileges.

SimpleUserInterface（UI）Implementation

Inadditiontocommoninterfacecontrolssuchastextboxes,menurings,andcheck-boxes,LabVIEWprovidesarichsetofUIcontrols（switches,LEDs,gauges,arraycontrols,etc.）thatarepertinenttolaboratoryequipment.ThesehavetheiroriginsinLabVIEWslaboratoryrootsandhelpindevelopmentofinterfaceswhichgivescientistsaclearunderstandingofasystem'

sstate.LabVIEWsupportsUIconceptsincludingsubpanels（similartotheMultipleDocumentInterface）,splitterbars,andXControls（analogoustoOCXcontrols）.

MultithreadedProgrammingEnvironment

TheinherentparallelenvironmentofLabVI