ABB DCS培训课程T31514 CommunicationRevA.docx

ABB DCS培训课程T31514 CommunicationRevA.docx

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ABBDCS培训课程T31514CommunicationRevA

Chapter14Communications

TABLEOFCONTENTS

Chapter14Communications1

14.1GeneralInformation2

14.1.1Objectives2

14.1.2Legend2

14.2MMSCommunicationbetweenApplications3

14.2.1General3

14.2.2MMSCommunicationPrinciple3

14.2.3Accessvariables4

14.2.4MMSVariableRules5

14.2.5VariableAttributes5

14.3ReadingDatafromanAccessVariable6

14.3.1PerformanceConsiderationsandStructuredAccessVariables7

14.4SetupanMMSCommunication8

14.4.1HowtoConfiguretheAccessDataType8

14.4.2HowtoDefinetheAccessVariable10

14.4.3HowtoReadAccessVariablesfromAnotherApplication11

14.4.4HowtoExtendParameters13

14.5OtherFunctionBlocksintheMMSCommLib15

14.5.1SIL2certifiedfunctionblocks15

14.6CommunicationtoOtherDevices17

14.6.1CommunicationLibraries17

14.6.2HardwareConfiguration18

14.6.3SoftwareConfiguration18

14.6.4AddressSyntax20

14.7HowtoConfigureaSerialCommunicationChannel21

14.7.1SerialConnect21

14.7.2SerialListen22

14.1GeneralInformation

14.1.1Objectives

Oncompletionofthischapteryouwillbeableto:

∙DescribetheprincipleofMMScommunication

∙Createanddefineaccessvariables

∙Configurecommunicationbetweencontrollers

∙ExplaintheuseofthedifferentMMSblocks

14.1.2Legend

<>Indicatesakeyname.

|Indicateswhenyougofromonemenutoasub-menu.

BoldIndicatesamenunameoranoptioninamenu,orfilestructures

““Indicatesdialogboxbuttons,tabs,instructionsetc.

Indicatesstart/explanationofstudentactivity

14.2

MMSCommunicationbetweenApplications

14.2.1General

MMSstandsforManufacturingMessageSpecification.Itistheprotocolusedtocommunicateonthecontrolnetworkbetweenapplicationsandalsototheconnectivityserverforthe800xAAspectSystem.

MMSsupportstransferofsimpleandstructuredvariables,programdownloadandalarmhandling.MMSisalsousedtodefineandmakedataavailableasAccessvariables.

GenerallytheMMScommunicationbetweenAC800Mcontrollersshouldbelimitedifpossiblebecauseitwillusethecontroller’sCPUcapacity.

14.2.2MMSCommunicationPrinciple

MMScommunicationhandlescommunicationbetweenapplicationswithinoneAC800Mcontrollerandbetweenapplicationsallocatedtotwocontrollers.

Theapplicationsmayexistinthesamecontroller:

Orindifferentcontrollersonthecontrolnetwork:

RememberthatinControlBuilderProfessionaloneapplicationdoesnotnecessarilycorrespondtoonecontrolsystem.Itispossibletoexecutetwoapplicationswithinthesamecontroller.Eveninthiscasethough,weneedtouseMMScommunicationwithAccessVariablesifwewantexchangedatabetweenthetwoapplications.

NOTE!

TheMMScommunicationshouldbelimitedandnotbeusedforalotofdata.

Forinstance:

don’twriteanapplicationinonecontrollerandusetheIOsofanothercontrollerforthisapplication.

14.2.3

Accessvariables

ForcommunicationbetweentwoApplications,Accessvariablesaredefined.AnAccessvariableisavariablethatissharedonthenetwork.

Bysharingalocal（orglobal）variableasanAccessvariable,itcanbepickedupbyanysystemonthenetwork,aslongasthetwosystemsinquestionshareacommonprotocol,suchasMMS,COMLIetc.

AccessVariablesaredefinedintheControllerHardwarepartoftheProjectExplorer:

Accessvariablesaredefinedinaparticularcontroller.TheremaybemanyAccessvariablesdefined.Suchvariablesaremappedintovariablesexistingintheapplicationsrunninginthatcontroller.ThismappingisdoneintheAccessVariableEditor.

Thevariableintheapplicationwhichismappedcanbeanyvariableexistinganywhereinthewholeapplication:

∙VariableinaprogramorControlModule

∙Variable（globalorlocal）intheapplication

14.2.4

MMSVariableRules

MMSvariablescanonlybeaccessedbytheirnamewhichisastring.ThenamingrulesaredefinedinMMSratherthanaspartofcontrolbuilder,thereforetherearesomedifferencesintheserulescomparedtothestandardnamingrulesforvariablesinprogramsetc.

∙AnMMSaccessvariablenamecanbeupto32characterslongandcontainletters,digitsandthecharactersdollar（$）andunderscore（_）.

∙NospacesarepermittedinthenameofanMMSvariable

∙MMSvariablenamesarecasesensitive,i.eisnotthesamevariableas.

∙Theaccessvariablenamecannotbeginwithadigitorthedollar（$）character.

∙Theaccessvariablemaybemappedtoanytypeofsimplevariableor（moreimportantly）toanytypeofstructuredvariable.

∙Astructuredvariablecanhavemixeddatatypecomponents

14.2.5VariableAttributes

BydefaultAccessvariablesareRead/Write.IfyouwanttomakethevariableReadOnlythensettheattributeintheAccessvariabletableto‘ReadWrite’

Iftheattribut