外文翻译基于PLC和组态软件的原油储罐区监督与控制系统.docx
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外文翻译基于PLC和组态软件的原油储罐区监督与控制系统
翻译部分
20093rdInternationalConferenceonPowerElectronicsSystemsandApplications
PLCandConfigurationSoftwareBasedSupervisoryandControl
SystemforOilTanksArea
XiCHEN1YanboCHE1K.W.ECHENG2
1SchoolofElectricalEngineering&Automation,TianjinUniversity,TianjinChina.
E-mail:
ybche@
2DepartmentofElectricalEngineering,TheHongKongPolytechnicUniversity,HongKong,
E-mail:
eeecheng@polyu.edu.HK
Abstract-AsupervisoryandcontrolsystemforoiltanksareabasedonPLCS7-300andconfigurationsoftwareForceControlisintroducedinthispaper.Thehardwarestructureofthesystemandthesoftwaredesignarebothdescribedindetail.Inthissystem,SuperiorcomputerscommunicatewithPLCthroughIndustrialEthernet.ThesuperiorcomputerssystemadoptsduplexredundancyandthePLCadoptssoftwareredundancy.ThismonitoringsystemintegratesthemeritofPLCandcomputerandimprovesthereliability.
Keywords-PLC,configurationsoftware,supervisoryandcontrolsystem,softwareredundancy
I.INTRODUCTION
Withtheincreasingcompetitionoftheoilmarketoildepotsareplayingamoreandmoreimportantrole,andithasbecomealong-termimportantjobtosuperviseandcontroltheoperationstateofoildepots.ThispaperdesignsasupervisoryandcontrolsystemforaoildepotinShandongProvince.Thisoildepotcollectedtankinformationandcontrolledvalvesmanuallybefore.Thereweresomeshortcomingsinitsuchasslowsupervisory,greaterrorandlowreliability.Soitisnecessarytoestablishabettersupervisoryandcontrolsystemthatistimely,accurateandreliable.ProgrammablelogiccontrollersPLChavebeenwidelyusedintheindustrialcontrolfieldsbecauseofitsmeritssuchassimplestructure,flexiblefunctions,highreliabilityandstrongabilityincommunication.Computershaveadvantagesinthedatadisplayandstorage,aswellasinhuman-computercommunications.ThispaperdesignsasupervisoryandcontrolsystemforoiltanksareabasedonPLCandcomputer.PLCisthecontrolcentreanditcompletesallthedetailsofthecontroltask.ItconnectswithdigitalandanalogsignalsoffielddevicesthroughgeneralI/Ointerfaces,collectsandprocessfielddataaccuratelyandquickly,andcompletesthelogic,timing,countingandmathematicaloperationseasily.Computersprovidehuman-machineinterface,displaythefeildworkingstastedynamicly,andmakestheoperationeasy.ThesystemcombinestheadvantagesofPLCandcomputer,providesaremotereal-timemonitoringforthetanksarea,ensuresafetyandreliabilityandimprovestheworkefficiency.Consideringoildepot’shighrequirementsonreliabilityandcontinuity,redundancyschemeisdesignedtoimprovethereliabilityfurther.
II.HARDWAREOFTHESYSTEM
A.theOverallstructureandfunctions
Fig.1Overallstructurediagramofthesystem
ThestructureofthesupervisorysystemisshowninFig.1.Therearethreelevelsinthesystem:
thefirstlevelissuperiorcomputers.TheyconsistofdualredundantIndustrialComputersinstalledwithconfigurationsoftwareForceControlandplacedinthemonitoringcenterroom,thesecondlevelisS7-300PLCthatadoptssoftwareredundancyandisplacedinthelocalcontrolrooms,andthefielddevicesincludingelectricallyoperatedvalvesandliquidlevelswitchesformthethirdlevel.IndustrialComputersareconnectedtotheIndustrialEthernetthroughgeneralnetworkcardsandPLCisconnectedtothesamenetbyEthernetcommunicationmodule,sotheycouldaccomplishthecommunicationbyusingTCP/IPprotocol.PLCcollectsfeedbackdatesofelectricallyoperatedvalves,collectsthestatusofliquidlevelswitchesandopensorclosesvalvesaccordingtothecommandfromsuperiorcomputersandthecontrolprogramintheCPUmodule.Inaddition,PLCcompletestheinterlockcontrolofvalveandliquidlevelswitch.ByexchangingdatawithPLC,superiorcomputersinstalledwithForceControl,monitorelectricallyoperatedvalvesandliquidlevelswitchesinrealtimeandgivecommandtoPLCtocontrolthevalves.Redundancystructureisadoptedinthesystem.ForceControlhastakentheleadinprovidingcompletesupportforredundancyamongtheChina-madeconfigurationsoftwareproducts,anditsupportsdeviceredundancy,networkredundancyandsuperiorcomputerredundancy.Therearetwosuperiorcomputersinthesystem,primarystationandsecondarystation.Innormalconditions,onlytheprimarystationcommunicateswithPLCandthedatainthesecondarystationsynchronizewiththeprimarystationtomakeabackup.Iftheprimarystationfails,thesecondarytakesoverthejob.Andthejob20093rdInternationalConferenceonPowerElectronicsSystemsandApplicationsDigitalReference:
K210509077
couldcomebacktotheprimarystationormanuallyaftertheprimarystationreturnsnormal.ForceControlsupportsPLCredundancyandnormallycommunicationswiththemasterstationofthePLC.IfthemastersystemofPLCisintheeventoffailure,thecontroljobwouldbetakenoverbythereservesystem,ForceControlwoulddisconnectthecommunicationaccordingtotheswitchflagandturntothereservestationtoexchangedates.
B.HardwareDesignofPLCSystemBeforeselectingPLCmodules,analyzethecontrolledobjecttocountoutI/Opoints.Thecurrentrequirementand20%-30%marginshouldbeconsidered,allowingthesystemtoexpand.Accordingtothisprinciple,I/Opointsareasfollows:
125digitalinputs,21analoginputs,84digitaloutputs.Basedontheanalysisofcontroltask,thesystemchoosesSiemensS7-300seriesofproducts.ThisseriesPLCcouldMeetrequirementsofthemedium-performancecontrolsystemandadoptmodularstructure.Manydifferentmodulescanbecombinedtogetherandusersshouldselectappropriatemodulesaccordingtotheactualneed.PLCmodulesselectedareshowninTable1.
PLCinthesystemconsistsoftwoS7-300stationseachwithaCPU315-2DPandtwoET200Mslavestations.ItsstructureisshowninFigure2.TheEthernetcommunicationmoduleCP343-1providesastandardRJ45interface,oneofthefunctionsistoconnectthePLCtoIndustrialEthernettocommunicatewithcomputers,andtheotherfunctionistoprovideredundantbackuplinkformasterCPUandreserveCPUtorealizeredundantcommunicationbetweenthetwoCPUs.
Fig.2HardwarestructureofPLC
CPU315-2DPprovidesDPmasterinterfaceandIM153-2ofET200MprovidestwoDPslaveinterfaces,oneisconnectedtothemasterstationandtheothertothereservestationthroughPROFIBUS-DPnetworks.PROFIBUS-DPcouldbeShieldedTwistedPair（RS485）networkphysically.NormalET200Mconsistofarail,ainterfacemoduleandsomegeneralmodules.Themodulesexceptpowersupplyareconnectedthroughbusconnectors.Thisstructuredoesn’tsupportredundantcyfunctions.Thereisanotherconfigurationthatissuitableforredundantcy.Itusesaspecialrailthatcantakeactivebusmodulesandtwointerfacemodules.Themodulesexceptpowersupplyaremountedontheactivebusmodulesanditispossibletochangemodulesduringrunning.
C.ConnectionsoftheElectricallyOperatedValveHenchunCKDserieselectricoperatorsareusedandFig.3showsitsconnectionmethod.Thefeedbackofelectricallyoperatedvalveincludesfourdigitalsignalsandoneanalogsignal.Digitalsignalsareremotemodeindicatingcontact,fullopenindicatingcontact,fulloffindicatingcontactandcommonalarmcontact.Theanalogfeedback,a4-20mAcurrent,showsthevalve’sopeningvalue.Whenthevalveisintheremotecontrolmode,digitaloutputsofPLCdrivetherelaysandthencontrolthevalves.Fouroutputcontrolsignalsincludeopen-valvesignal,close-valvesignal,stopsignalandemergencyprotectionsignalesd.
Fig.3Valveconnectiondiagram
III.SOFTWAREOSTHESYSTEM
Softwareinthesystemincludestwomajorparts,PLCprogrammingsoftwareSTEP7V5.4andsuperiorcomputerconfigurationsoftwareForceControlV6.0.
A.CommunicationbetweenSuperiorComputerandPLC
ForceControldevelopsaspecialdriverfortheS7-300PLC,20093rdInternationalConferenceonPowerElectronicsSystemsandApplications
DigitalReference:
K210509077
thereforeitisnotnecessaryfortheuserstobefamiliarwiththecommunicationprotocolbetweenthem,andneithernecessarytoprogramorconfigurenetworkinthePLC,thecommunicationbetweenPCandPLCcanbeachievedeasily.ThemainprobleminthissystemisthatduetoPLC'ssoftredundantstructure,whenthecontroltaskswitchestoresereveCPUfromthemasterone,ForceControlshouldswitchtothecorrectcommunicationobjecttoexchangedatas.Forthispurpose,whendevicePLCiscreatedinForceControl,itshouldbeconfiguredproperlyandadatapointshouldbedefinedinthereal-timedatabaseasaredundancyswitchingflag.
FirstconfigureI/OdeviceforForceControl,createPLCwhoseequipmentaddressissetto2,ifsetto1,ForceControlwillnotbeabletoconnecttothePLC.ThestandbychannelisenabledandthedeviceIPaddressandstandbyIPaddressshouldcorrespondwithPLC’stwoEthernetcommunicationmodulesCP343-1.AfterI/OdevicePLCiscreated,defineadatapointinreal-timedatabasewhosedatatypeisselectedas"redundancyswitchingflag".Theflag’svalueis0innormalstate,whenitsvalueis1,ForceControlwillswitchtoPLC’sanotherIPaddress,thenthevalue1willbeclearedautomatically.HerethedatapointislinkedwithMW16ofPLC.CorrespondingprogramisloadedintoPLC,whentheCPUisworkingasmasterstation,MW16issetto0,whentheCPUisworkingasreservestation,MW16issetto1,programinPLCisasfollows:
LDB5.DBB9
LW#16#2
AW
SRW1
TMW16
B.Softwar
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