ABB DCS 系统 培训课程 系列讲座 Control Modules.docx

ABB DCS 系统 培训课程 系列讲座 Control Modules.docx

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ABBDCS系统培训课程系列讲座ControlModules

Chapter17ControlModules

17.1GeneralInformation

17.1.1Description

ThischapterdescribestheadvantagesofControlModulesandhowtouseandmodifythem.ThischapteralsogivesanideeofhowtoorganizetheprojectwhenapproachingitinanobjectorientedwayusingControlModules.

17.1.2Objectives

Oncompletionofthischapteryouwillbeableto:

∙DescribethedifferencesbetweenControlModulesandFunctionBlocks.

∙DescribewhenitissuitabletouseControlModules.

∙TheinstantiationofControlModules.

∙ConnectControlModulestoparameters/variables.

∙UseControlModulesinthegraphics.

∙ModifyaControlModule.

∙CreateControlModulesusingotherControlModules,inanewlibrary.

∙Visualizingtheprogramusinggraphics.

∙Describetheideaofobjectorientation.

∙Describetheadvantages/drawbacksofconnectingtoI/Oindifferentdepths（toglobalvariables,toprogramvariables,toFBvariables,usinganI/O-recordetc.）.

∙CreatesimpleinteractionwindowsassociatedtoFunctionBlocksorControlModules.

17.1.3ReferenceDocumentation

Usetheonlinehelp:

Contentstab,ControlModuleDiagramEditor

17.2Lesson1-UsingControlModules

17.2.1Description

ThislessondescribestheadvantagesoftheABBControlModulesandisanintroductiontohowanApplicationcanbeorganizedwhenusingthem.

17.2.2Objectives

Oncompletionofthislessonyouwillbeableto:

∙DescribethedifferencesbetweenControlModulesandFunctionBlocks.

∙DescribewhenitissuitabletouseControlModules.

∙TheinstantiationofControlModules.

∙ConnectControlModulestoparameters/variables.

∙UseControlModulesinthegraphics.

17.2.3General

TheControlModuleisthemainstructuringelementforcontrollerapplicationprogramming.Itisaself-executablecontainerforapplicationprogramcodeandgraphics.BecauseaControlModuleinvolvesgraphicalobjects,youcreateitbyusingnotonlythePOUEditor,butalsotheControlModuleeditor.ControlModulesaresuitableforrepresentingcomplexprocessobjectsandcontroloflargeapplications.WorkingwithControlModulesinvolvesthoroughobjectorientedprogramming,asmuchoftheobjectcontrolaspossibleshouldbeencapsulatedintheControlModuleandtheoutwarddependencyshouldbeminimized.Apartfromconventionalprogramming,theControlModuledesignmayinvolveimplementationofgraphicalinteractivity.

ThecompilerdeterminestheapplicationdataflowandexecutionorderofControlModulesautomatically.Therefore,thefinalapplicationgetsflexibleandeasytomaintainasintegrationoffutureadditionalControlModulesaredoneautomatically.ControlModulescanbestructuredhierarchicallyinanumberoflevels.YoucanusethesameControlModuleTypeforseveralControlModules,eachperformingdifferenttasksdependingonparameterconnections.

17.2.4

DifferencebetweenFunctionBlockandControlModule

17.2.4.1GeneralComparison

ThemostimportantdifferencesbetweenControlModulesandFunctionBlocksaresummarizedinthetablebelow.

Property

ControlModule

FunctionBlock

Executionorder*

Automatic;compilerdetermined,basedondataflow.

Manual;codestatements,basedonprogramflow.

Executionperscan

Thecodeblocksarealwaysexecutedonceperscanaccordingtodataflowanalysis.

Afunctionblockcanbecalledandexecuted,zero,one,orseveraltimesperscan.

Staticparameterconnections*

Yes.Amostimportantfeature:

Astaticparameterconnectiondoesnotchangeduringexecution;itcanonlybechangedviacodechangesandrecompilation.Thestaticconnectionsaresetatcompiletimeandyieldsefficientcodegeneration;powerful,compiler-basedprogramanalysis;andbetterperformance.

No.ParametersarecopiedeachtimetheFunctionBlockisexecutedaccordingtotheIEC61131-3standard.Fordeepandcomplexhierarchies,theparametercopyingoffunctionblockscostssignificantCPUtime.

Graphics*

Yes,inthreedifferentways;free-layoutprogramming,supervision,andinteraction.

IndirectlyviainclusionofsubControlModules.

Parameters

In_out,canbeconnectedtographics.Connectionscannotbeinverted:

NOT"actualparametername"isinvalid.）.

In,Out,orIn_out,onlyIn-andOutparameterscanbeconnectedtosubcontrolmodules.

Together,thepropertiesmarkedwith*facilitatedesignofapplicationlibrariesandre-useofcomplexapplicationbuildingblocks.

17.2.4.2Graphics

YoucandesignaControlModuletoincludeinteractiveandsupervisoryprocesspictures（suchascommandbuttons,inputfieldsandtrendcurves）.Inaddition,ControlModulescanberepresentedbycertaininteractiveiconswhichfacilitatestheprocesscontrolandsupervision.

17.2.4.3Executionandcodesorting

ThemaindifferencebetweenControlModulesandFunctionBlocksisthatControlModulesareexecutedinanorderbasedonoptimaldataflow,asdeterminedbythecompiler.TheexecutionorderofFunctionBlocksfollowstheprogramflowasimplementedbytheprogrammer.ControlModulesareonlyexecutedonceperscanwhereasFunctionBlocksmaybeexecutedseveraltimesperscan.

17.2.5WhenisitsuitabletouseControlModules

Beforeyoustarttodesignanapplication,youshoulddecidewhethertousetraditional（sequential）programcodeandfunctionblocksoranobject-orientedsolutionbasedoncontrolmodules.Apartfrompersonalpreferences,thechoicewouldtypicallydependonapplicationsizeandtheneedforre-usableobjects.

Asageneralguideline,traditionalprogrammingistypicallysuitableforsmallapplicationswhereascontrolmodulesarerecommendedforlargeapplications.Controlmodulessupportobject-orientedprogrammingandcodere-usetoagreaterextentandthereforemakealargeapplicationmoreflexibleandeasiertomaintain.

Thesubsequentimplementationwillfollowoneofthebranchesinthefigurebelow.

Thefigureshowsthatalsotheobject-orientedsolutiontypicallyinvolvesfunctionblocks.Thisisbecauseobjectorientationbelowacertaincomplexitylevelisnotjustifiable.Inthiscase,traditionalprogrammingwithfunctionblocksconstitutesthemostrationalalternative.

Insummary,itisrecommendedtousecontrolmodulesratherthanfunctionblocksinthefollowingcases:

∙Forlargeapplications（increasedperformance）

∙Forprocessobjects（codesortingfacilitatesapplicationstructuring）

∙Whenaflexiblesolutionisneeded（objectorientation;re-useisdesired）

∙Whenthereisaneedtoconcentratethecontrolofacertainobjecttoonecodelocation（facilitatesmaintenance）

17.2.5.1

TheControlModuleeditors

TheControlModuleeditorisacombinedtoolfordrawingandprogramming,itallowsyoutocreateandeditthegraphicalobjectsofaControlModuleandthenconnectvariablestotheseobjects.ItalsogivesyoudirectaccesstothePOUeditor,inwhichyouwritetheControlModulecodeanddeclarevariablesandparameters.

YoucanbothcreatenewControlModulesandeditalreadyexistingoneswiththeControlModuleeditor.Thedrawingfunctionsincludenotonlybasicautoshapes（lines,rectangles,etc.）,butalsoreadytouseinteractionobjects（OptionButtons,CheckBoxes,etc.）andcompositeobjects（HistoryGraphs,StringSelectors,etc.）.Thegraphicalobjectsaredynamic,thatispointscanmovewithchangingvariablevalues,colorscanchange,numericalvaluescanbepresented,etc.

17.2.6CreatingaControlModule

17.2.6.1Introduction

AControlModulecanbecreatedeitherfromtheProjectExplorerdirectly（textgenerated）orfromaControlModulesWindow（graphicsgenerated）.Thefollowinggeneralpropertiesapply:

∙AControlModulealwayshasaparentPOU.ThisPOUTypecanbeaControlModuleType,FunctionBlockType,oranapplication.

∙AControlModulecanbeshowngraphicallyinsidethegraphicoftheparent（iftheparentisamoduletypeoranapplication）.

∙AControlModulecanalsobeshown（standalone）inaninteractionwindow（inonlinemodeonly）.

17.2.6.2CreateaNew,Graphics-GeneratedControlModule

Right-clickonacontrolmoduletypeintheprojecttreeandselecttheGraphicsentrytoopentheControlModuleTypeWindow.Double-clickinthedrawingareatoactivatethegrid.SelectCreate>ControlModule...toopenthe"CreateaControlModule"dialogboxinwhichyouspecifytheControlModulenameandassociatedType.Exceptforthatagraphics-generatedControlModulebydefaultbecomesgraphicallyvisible,theaboveprinciplesapply.

17.2.7Connections

ControlModulescanbeconnectedtoeachotherintwodifferentways;viagraphicsandviatext.Youimplementgraphicalconnectionsinthecontrolmoduleswindoworthecontrolmoduletypewindowandtext-basedconnectionsintheConnectionEditor.

YoucanreachtheConnectionEditorviatheConnectionsentry,accessiblewhenacontrolmoduleisselected,choose（Objects>Connections）orConnectionsfromright-clickpop-upmenu.Acontrolmoduledesignedtobegraphicallyconnectedhavetobebuiltwiththenodesinplace,readyforlaterconnection.Graphicalconnectionsaresuitableforobtainingacomprehensiveviewofmainflows,forexampleinaPIDControllercomprisinganinputcontrolmodule,amaincontrolmodule,andanoutputcontrolmodule.（Yet,observethatabundantuseofgraphicalconnectionsmayslowdownthesystem.）

17.2.7.1Textualconnection

ParameterscanbeconnectedtoactualvariablesintheconnectionlistoftheConnectionEditor.Itisnotpossibletoconnectthesameparameterbothgraphicallyandtextually.TextualconnectionistheonlywaytoconnectparameterswhenthecontrolmoduleissubordinatetoaFunctionBlock,asnosurroundinggraphicsthenexist.

17.2.7.2Graphicalconnection

Graphical