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1、附录A英文原文ElevatorSystemBasedonPLCJohnR.HackWorth.FrederickD.HackWorthjrComposedbytheorderofrelaycontrolsystemisarealizationofthefirstelevatorcontrolmethod.However,toenterthenineties,withthedevelopmentofscienceandtechnologyandthewidespreadapplicationofcompute
2、rtechnology,thesafetyofelevators,reliabilityoftheincreasinglyhighdemandontherelaycontrolweaknessesarebecomingevident.Elevatorcontrolsystemrelaysthefailureratehigh,greatlyreducesthereliabilityandsafetyofelevators,andescalatorsstoppedoftentotakewiththestaffa
3、bouttheinconvenienceandfear.Andtheeventratherthantakingtheliftorsquatattheendoftheliftwillnotonlycausedamagetomechanicalcomponents,butalsopersonalaccidentmayoccur.ProgrammableLogicController(PLC)isthefirstorderlogiccontrolinaccordancewiththeneedsofdevelope
4、dspecificallyforindustrialenvironmentapplicationstooperatetheelectronicdigitalcomputingdevice.Givenitsadvantages,atpresent,therelaycontrolthelifthasbeengraduallyreplacedbyPLCcontrol.Atthesametime,ACvariablefrequencymotorspeedcontroltechnology,thewaythelift
5、dragspeedhasbeenagradualtransitionfromDCtoACfrequencyconverter.Thus,PLCcontroltechnologyincreasesVVVFElevatormoderntechnologyhasbecomeahotindustry.1.PLCelevatorcontroladvantages(1)usedinelevatorcontrolPLC,withsoftwareforautomaticcontrolofliftoperation,reli
6、abilitygreatlyincreased.(2)layerwasremovedandamajorityoftherelay,thecontrolsystemstructureissimple,tosimplifytheexternalcircuit.(3)PLCcanbeavarietyofcomplexcontrolsystem,easytoaddorchangecontrolfunctions.(4)PLCcanbeautomatedfaultdetectionandalarmdisplaytoi
7、mprovetheoperationofsecurityandeaseofmaintenance.(1)forthegroupcontroltheallocationandmanagement,andimprovetheefficiencyofelevatoroperation.(2)donotneedtochangethecontrolschemechangeswhenthehardwareconnection.1.VVVFelevatorcontrolcharacteristicsWiththepowe
8、relectronics,microelectronicsandcomputertechnologytocontroltherapiddevelopmentoftechnology,communicationtechnologyVVVFalsoaveryrapidrate.ACvariablefrequencymotorspeedcontroltechnologyisthepowertoimprovethepro
