外文翻译原文-基于PLC的电梯控制系统的设计和实现

DesignandPracticeofanElevatorControlSystemBasedonPLCXiaolingYang1,2,QunxiongZhu1,HongXu11CollegeofInformationScience&Technology,BeijingUniversityofChemicalTechnology,Beijing100029,China2AutomationCollegeofBeijingUnionUniversity,Beijing,100101,Chinayxl_,,AbstractThispaperdescribesthedevelopmentof2nine-storeyelevatorscontrolsystemforaresidentialbuilding.ThecontrolsystemadoptsPLCascontroller,andusesaparallelconnectiondispatchingrulebasedonminimumwaitingtimetorun2elevatorsinparallelmode.Thepapergivesthebasicstructure,controlprincipleandrealizationmethodofthePLCcontrolsystemindetail.Italsopresentstheladderdiagramofthekeyaspectsofthesystem.Thesystemhassimpleperipheralcircuitandtheoperationresultshowedthatitenhancedthereliabilityandperformanceoftheelevators.1.IntroductionWiththedevelopmentofarchitecturetechnology,thebuildingistallerandtallerandelevatorsbecomeimportantverticaltransportationvehiclesinhigh-risebuildings.Theyareresponsibletotransportpassengers,living,workingorvisitinginthebuilding,comfortableandefficientlytotheirdestinations.Sotheelevatorcontrolsystemisessentialinthesmoothandsafeoperationofeachelevator.Ittellstheelevatorinwhatordertostopatfloors,whentoopenorclosethedoorandifthereisasafety-criticalissue.Thetraditionalelectricalcontrolsystemofelevatorsisarelay-controlledsystem.Ithasthedisadvantagessuchascomplicatedcircuits,highfaultratioandpoordependability;andgreatlyaffectstheelevatorsrunningquality.Therefore,entrustedbyanenterprise,wehaveimprovedelectricalcontrolsystemofarelay-controlledelevatorinaresidentialbuildingbyusingPLC.Theresultshowedthatthereformedsystemisreliableinoperationandeasyformaintenance.Thispaperintroducesthebasicstructure,controlprincipleandrealizationmethodoftheelevatorPLCcontrolsystemindetail.2.SystemstructureThepurposeoftheelevatorcontrolsystemistomanagemovementofanelevatorinresponsetousersrequests.Itismainlycomposedof2parts:2.1.ElectricpowerdrivingsystemTheelectricpowerdrivingsystemincludes:theelevatorcar,thetractionmotor,doormotor,brakemechanismandrelevantswitchcircuits.HereweadoptedanewtypeofLCseriesACcontactorstoreplacetheoldones,andusedPLCscontactstosubstitutetheplentyofintermediaterelays.Thecircuitsoftractionmotorarereserved.Thustheoriginalcontrolcabinetsdisadvantages,suchasbigvolumeandhighnoiseareovercomeefficiently.2.2.SignalcontrolsystemTheelevatorscontrolsignalsaremostlyrealizedbyPLC.Theinputsignalsare:operationmodes,operationcontrolsignals,car-calls,hall-calls,safety/protectsignals,dooropen/closesignalandlevelingsignal,etc.AllcontrolfunctionsoftheelevatorsystemarerealizedbyPLCprogram,suchasregistration,displayandeliminationofhall-callsorcar-calls,positionjudgmentofelevatorcar,chooselayeranddirectionselectionoftheelevator,etc.ThePLCsignalcontrolsystemdiagramofelevatorisshowedinFigure1.Figure1PLCsignalcontrolsystemdiagram2.3.RequirementsThegoalofthedevelopmentofthecontrolsystemistocontrol2elevatorsina9-storeyresidentialbuilding.Foreachelevator,thereisasensorlocatedateveryfloor.Wecanusethesesensorstolocatethecurrent2008WorkshoponPowerElectronicsandIntelligentTransportationSystem978-0-7695-3342-1/08$25.002008IEEEDOI10.1109/PEITS.2008.4494positionoftheelevatorcar.Theelevatorcardoorcanbeopenedandclosedbyadoormotor.Thereare2sensorsonthedoorthatcaninformthecontrolsystemaboutthedoorsposition.Thereisanothersensoronthedoorcandetectobjectswhenthedoorisclosing.Theelevatorcarsupordownmovementiscontrolledbyatractionmotor.Everyfloor,exceptthefirstandthetopfloor,hasapairofdirectionlampsindicatingthattheelevatorismovingupordown.Everyfloor,hasasevensegmentLEDtodisplaythecurrentlocationoftheelevatorcar.Thefirststepforthedevelopmentoftheelevatorcontrolistodefinethebasicrequirements.Informally,theelevatorsbehaviorisdefinedasfollows.(1)RunningwithasingleelevatorGenerally,anelevatorhasthreeoperationstates:normalmode,fire-protectionmodeandmaintenancemode.Themaintenancemodehasthehighestpriority.Onlythemaintenancemodeiscanceledcantheotheroperationmodesbeimplemented.Thenextisfire-protectionmode,theelevatormustreturntothebottomfloororbasestationimmediatelywhenthefireswitchacts.Theelevatorshouldturntonormaloperationmodewhenthefireswitchisreset.Undernormaloperationmode,thecontrolsystemsbasictaskistocommandeachelevatortomoveupordown,tostoporstartandtoopenandclosethedoor.Butishassomeconstraintsasfollows:Eachelevatorhasasetof9buttonsonthecarcontrolpanel,oneforeachfloor.Thesebuttonsilluminatewhentheyarepressedandcausetheelevatortovisitthecorrespondingfloor.Theilluminationiscanceledwhenthecorrespondingfloorisvisitedbytheelevator.Eachfloor,exceptthefirstandthetopfloor,hastwobuttonsonthefloorcontrolpanel,onetorequestanup-elevator,onetorequestadown-elevator.Thesebuttonsilluminatewhentheyarepressed.Theilluminationiscanceledwhenanelevatorvisitsthefloor,thenmovesinthedesireddirection.Thebuttonsonthecarcontrolpanelorthefloorcontrolpanelareusedtocontroltheelevatorsmotion.Theelevatorcannotpassafloorifapassengerwantstogetoffthere.Theelevatorcannotstopatafloorunlesssomeonewantstogetoffthere.Theelevatorcannotchangedirectionuntilithasservedallonboardpassengerstravelinginthecurrentdirection,andahallcallcannotbeservedbyacargoinginthereversedirection.Ifanelevatorhasnorequests,itremainsatitscurrentfloorwithitsdoorsclosed.(2)ParallelrunningwithtwoelevatorsInthissituation,therearetwoelevatorstoservethebuildingsimultaneously.Itrunsat7amto9amand5pmto7pmeveryday.Whenanelevatorreachesalevel,itwilltestifthestopisrequiredornot.Itwillstopatthislevelwhenthestopisrequired.Atthesametime,tobalancethenumberofstops,theoperationoftwoelevatorswillfollowacertaindispatchingprinciple.Anelevatordoesntstopatafloorifanothercarisalreadystopping,orhasbeenstoppedthere.Thenormaloperationofelevatorsisimplementedbycooperationofitselectricpowerdrivingsystemandlogiccontrolsystem.3.SoftwaredesignDuetotherandomnatureofcalltime,calllocationsandthedestinationofpassengers,theelevatorcontrolsystemisatypicalreal-time,randomlogiccontrolsystem.HereweadoptedcollectiveselectivecontrolmethodwithsiemensPLCS7-200CPU226anditsextensionmodules.Thereare46inputpointsand46outputpointsinthesystem.TheI/OpointsareshowedinTable1andTable2.Table1Inputpointsdescriptionaddress1-8flooruphall-callI0.0-I0.72-9floordownhall-callI1.0-I1.71-9floorcar-callI2.0-I2.7,I3.01-9arrivalsensorI3.1-I3.7,I4.0-I4.1dooropenbuttonI4.2doorclosebuttonI4.3doorcloselocationswitchI4.4dooropenlocationswitchI4.5uplevelingsensorI4.6downlevelingsensorI4.7fireswitchI5.0driveroperationswitchI5.1touchpanelswitchofcardoorI5.2overloadI5.3ForcedspeedchangingswitchI5.4fullloadI5.5Table2Outputpointsdescriptionaddress1-8flooruphall-calllampQ0.0-Q0.72-9floordownhall-calllampQ1.0-Q1.71-9floorcar-calllampQ2.0-Q2.7,Q3.0upmovinglampQ3.1downmovinglampQ3.2SevensegmentLEDdisplayofelevatorspositionQ3.3-Q3.7Q4.0-4.1dooropeningQ4.2doorclosingQ4.3upmovingQ4.4downmovingQ4.5fullloadlampQ4.6highspeedoperationQ4.7lowspeedoperationQ5.0accelerationofstartingQ5.1decelerationofbrakingQ5.2-Q5.4alarmbeeperQ5.5Aboutsoftwaredesigning,weadoptthemodularizedmethodtowriteladderdiagramprograms.TheinformationtransmissionbetweenmodulesisachievedbyintermediateregisterbitofPLC.95Thewholeprogramismainlycomposedof10modules:hall-callregistrationanddisplaymodule,car-callregistrationanddisplaymodule,thesignalcombinationmodule,thehall-callcancelmodule,theelevator-locationdisplaymodule,thefloorselectionmodule,themovingdirectioncontrolmodule,thedooropen/closemodule,themaintenanceoperationmoduleandthedispatchingmoduleunderparallelrunningmode.Thedesignofthetypicalmodulesisdescribedasfollows:3.1.Hall-callregistrationanddisplayTherearetwokindsofcallsinanelevator:hall-callandcar-call.Whensomeonepressesabuttononthefloorcontrolpanel,thesignalwillberegisteredandthecorrespondinglampwillilluminate.Thisiscalledhall-callregistration.Whenapassengerpressesabuttonintheelevatorcar,thesignalwillberegisteredandwiththecorrespondinglampilluminated.Thisiscalledcar-callregistration.Figure2showstheladderdiagramofuphall-callsregistrationanddisplay.Theself-lockprincipleisusedtoguaranteethecallscontinuousdisplay.Figure2uphall-callregistrationanddisplay3.2.ThecollectiveselectionofthecallsHerethecollectiveselectioncontrolrulesareused.AsshowedinFigure3,M5.1-M5.7,M6.0andM6.1areauxiliaryrelaysinPLC.Theydenotethestoppingrequestsignalof1stto9thfloorrespectively.TheauxiliaryrelayM6.2denotestheelevatordriversoperationsignal.Whenthereisacallinacertainfloor,thestoppingsignalofcorrespondingfloorwilloutput.Whentheelevatorisoperatedbythedriver,thehall-callswillnotbeserved.Andtheelevatorcannotpassaflooratwhichapassengerwishestoalight.3.3.ThecancellationofthecallsTheprogramofthismodulecanmaketheelevatorresponsethehall-callswhichhavethesamedirectionasthecarscurrentdirection,andwhenahall-callisserved,itsregistrationwillbecanceled.Theladderdiagramofuphall-callscancellationisshowedinFigure4.Figure3ThecombinationofthecallsFigure4ThecancellationofupcallsInFigure4,theauxiliaryrelayM4.0istheupmovingflagoftheelevator.Whenthecurrentdirectionoftheelevatorisup,M4.0scontactsareclosed;onthecontrary,whenthecurrentdirectionoftheelevatorisdown,M4.0scontactsareopened.M0.1toM0.7denotesthecar-callsstoppingrequestsignaloffloor2tofloor8respectively.Thisprogramhastwofunctions:(1)Maketheelevatorresponsethenormaldownhall-callswhenitismovingdown,andwhenadownhall-callisserved,itsregistrationiscanceled.(2)Whentheelevatorismovingup,thecorrespondingfloorsdownhall-callitpassingbyisnotservedandtheregistrationisremained.96Thecancellationofdownhall-callsisreversedwithuphall-calls.3.4.ElevatorsdirectionTheelevatormaybemovingupordown,dependingonthecombinationofhall-callsandcar-calls.ThefollowingladderdiagraminFig.5illustratesthattheelevatorwillmoveup.Figure5UpmovingoftheelevatorFigure5showsthatwhenthecallscorrespondingfloorishigherthantheelevatorscurrentlocation,theelevatorwillgoup.HeretheauxiliaryrelayM4.0isusedastheup-movingflag.Whentheelevatorismovingup,theup-movinglampisilluminated,sotheM4.0isconnectedon.Whentheelevatorarrivesthetopfloor,theup-movinglampisoffandthetimerstarts.After0.2s,theM4.0isdisconnected,theup-movingdisplayisoff.HereweusedM4.0toreplaceQ3.1whichcanensurethecancellationsreliability.3.5.Elevatorsfloor-stoppingFigure6showstheladderdiagramoftheelevatorsfloor-stoppingfunction.AsshowedinFigure6,M6.4istheflagoffloor-stoppingsignal.M6.6isthefloor-stoppingsignalsentbythedriver.M7.0isthefiresignalsentbythefireswitch.AndM6.7istheforcedspeedchangingsignal.Wheneitherofthesecontactsact,thesystemshouldsendoutthefloor-stoppingsignal.4.MinimumwaitingtimealgorithmIntrafficofelevatorsystems,therearetwotypesofcontroltaskusually.Theoneisthebasiccontrolfunctiontocommandeachelevatortomoveupordown,tostoporstartandtoopenandclosethedoor.Theotheristhecontrolofagroupofelevators.Themainrequirementsofagroupcontrolsysteminservingboth,carandhallcalls,shouldbe:toprovideevenservicetoeveryfloorinabuilding;tominimizethetimespentbypassengerswaitingforservice;tominimizethetimespentbypassengerstomovefromonefloortoanother;toserveasmanypassengersaspossibleinagiventime1.Figure6Theelevatorsfloor-stoppingTherearemanydispatchingalgorithmsforelevatorsgroupcontrol.SuchasNearest-neighborAlgorithm2,whichtheelevatoralwaysservetheclosetrequestnext;ZoningAlgorithm3whichbyanalyzingthetrafficofelevatorsystemwithunequalfloorandpopulationdemandtodispatchtheelevator;andOdd-evenrule,whichanelevatoronlyservestheoddfloorandtheotheronlyservestheevenfloor.TheNearest-neighborAlgorithmminimizesthelengthoftheelevatorsemptymovetothenextrequest.itusuallyhasverysmallaveragewaitingtimes,butindividualwaitingtimescanbecomequitelarge2.TheZoningAlgorithmusuallyusedinbuildingswhichhasheavytrafficsituations,suchastheofficebuildingatlunchtime.Comparedtotheofficebuildingandshoppingmall,thetrafficflowofresidentialbuildingsisrelativelylow97andevenineveryfloor.Secondly,peopleusuallythinkofelevatorsaspurelyfunctionalobjectsandtheexperienceofridinganelevatoristimewaitedformostofthem.Furthermore,thereexistimmenseproblemswhenattemptingtosatisfyallrequirements.Consideringallofthereasonsabove,weadoptedthe“minimumwaitingtime”algorithmtorealizethe2elevatorsparallelrunning4.4.1.EvaluationfunctionThegoalofthe“minimumwaitingtime”algorithmistopredicttheeachelevatorsresponsetimeaccordingtoallcalls,andselecttheelevatorwhichhastheshortestresponsetimetoserve.Whenthereisacall,thesystemcalculatesoutthefunctionvaluesofeachelevatoraccordingtheevaluationfunctionshowedin(1)and(2):J(*)=MinJ(1),J(2),J(n)(1)J(i)=Tr(i)+KTd(i)+KTo(i)i=1,2,.,n(2)J(i)istheevaluationindexofeachelevator;Tr(i)denotesthetimeoftheelevatordirectlymovingtothedestinationcorrespondingthelatestcallfromitscurrentfloor;To(i)denotestheadditionalaccelerationanddecelerationtimeofafloor-stopoftheelevator;Td(i)denotestheaveragetimeofthepassengerboardingandalightingtheelevator;andKisthesumofhall-callsandcar-calls.Butwhenahall-callandacarcallcorrespondsthesamefloor,theKisonlycalculatedonetime.4.2.CalculationofminimumwaitingtimeInequation(2),Kisacertainvalue,ToandTdcanbeobtainedbymeansofstatistics.Tr=T*L,whereTdenotestheaveragetimeoftheelevatorpassingbyonefloor;Ldenotesthedesiredfloorsoftheelevatorfromcurrentfloortothehall-callfloor.InordertocalculatetheLvalue,wedefinedthe2elevatorsareAandBrespectively;YA,YBdenotesthecurrentfloorofelevatorAandBrespectively.Histhecorrespondingkeyvaluewhenahall-callbuttonispressed,andH=floornumberofthehall-call.Wedefined4tablesforthePLCrealization:uphall-callregistrationtable,downhall-callregistrationtable,car-callregistrationtableofAandcar-callregistrationtableofB.Whenacertaincallbuttonispressed,itsfloorvalueisrecordedincorrespondingtable.HerewetakeelevatorAasanexample.First,definethevariableMA,MBandMW.WhereMA,MBdenotestheextremevalueofcar-callswithsamedirectionofAorBsmovementrespectively.WhenelevatorAisup-moving,setMAisequaltothemaximumvalueincar-callregistrationtableA;whenelevatorAisdown-moving,setMAisequaltotheminimumvalueincar-callregistrationtableA.MWdenotestheextremevalueofhall-callswithsamedirectionofAsmovement.WhenelevatorAisup-movingandup-hall-callvalueYA,setMW=0;otherwise,setMWisequaltotheminimumvalueinup-hall-callregistrationtableA.WhenelevatorAisdown-movingandup-hall-callvalueYA,setMW=0;otherwise,setMWisequaltothemaximumvalueindown-hall-callregistrationtableA.Thus,wecandeterminetheLvalueaccordingtoYA,H,MAandMW.Thereare3situations:(1)Whenthehall-callsdirectionisoppositetoelevatorAsmovement:L=|YA-MA|+|MA-H|(3)(2)Whenthehall-callsdirectionissameaselevatorAsmovementanditisinthefrontofelevatorA:L=|YA-H|(4)(3)Whenthehall-callsdirectionissameastheelevatorAsmovementanditisinthebackofelevatorA:L=|YA-MA|+|MA-MW|+|H-MW|(5)Sothei-thfloorsminimumwaitingtimecanbecalculatedby(6)asfollows:Time(i)=TL(i)+KTd(i)+KTo(i)i=1,2,.,n(6)Whenthecallschangeduringtheoperationofelevators,thesystemcalculatestheminimumwaitingtimeofeachelevator.Thenitallocatesthecurrentcalltotheelevatorwhichhassmallvalue.Whentheeachelevatorhasthesamevalue,thenthecurrentcallispriortoelevatorA.Whenanelevatoriswrongornotinservice,thesystemcanexitthedispatchingalgorithmandturnstoasingleelevatorrunningmode.4.3.AlgorithmrealizationComparedwithsingleelevatorrunningmode,theparallelrunningmodeismainlydifferentattheprocessingmethodabouthall-calls.Theformerusescollectiveselectivecontrolmethod,andthelatterusesdispatchrulecombinedwithcollectiveselectivecontrolmethod.Herethesystemistocontrola9-storeybuilding,sowechoosetwoSiemensS7-200PLCs(CPU226)anditsExtensiveModulestocontrolthesingleelevatorrespectively.AndbyusingPPIProtocoltorealizethecommunicationbetween2PLCs.ThePPIProtocoladoptsmaster-slavecommunicationmode,sowedefinedelevatorAasthemasterandelevatorBastheslave.Bycommunicationprogram,the2PLCscanexchangethemassagesuchasthecurrentposition,hall-callsorcar-callsandmovingdirection.Thenbyusing“minimumwaitingtime”algorithm,thesystemrealizestheoptimaloperationof2elevators.Figure7showstheladderprogramofthecar-callsextremevaluecalculationofelevatorA.InFigure7,VB121VB130istheregisteraddressofelevatorAscar-callcorrespondingtoeachfloor,Q3.1is98theup-movinglampofelevatorA,andthecar-callsextremevalueissav