电气工程与自动化专业英语 教学课件 作者 王伟 8.pptx

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1、Chapter8ProgrammableLogicControllerTechnology8.1　Introduction8.1.1　CPU-CentralProcessingUnit8.1.2　Memory8.1.3　ProgrammingaPLCController8.1.4　PowerSupply8.1.5　PLCControllerInputs8.1.6　InputAdjustmentInterface8.1.7　PLCControllerOutput8.1.8　OutputAdjustmentInte

2、rface8.1.9　ExtensionLines8.1　IntroductionFig.8-1　BasicelementsofPLCcontroller8.1.1　CPU-CentralProcessingUnitPLC(ProgrammableLogicController)isactuallyanindustrialmicrocontrollersystem(inmorerecenttimeswemeetprocessorsinsteadofmicrocontrollers)whereyouhavehar

3、dwareandsoftwarespecificallyadaptedtoindustrialenvironment.Itisadevicethatwasinventedtoreplacethenecessarysequentialrelaycircuitsformachinecontrol.1ThePLCworksbylookingatitsinputsanddependingupontheirstate,turningon/offitsoutputs.Theuserentersaprogram,usuall

4、yviasoftwareorprogrammerthatgivesthedesiredresults.8.1.2　MemorySystemmemory(todaymostlyimplementedinFLASHtechnology)isusedbyaPLCforanprocesscontrolsystem.Asidefromthisoperatingsystemitalsocontainsauserprogramtranslatedfromaladderdiagramtoabinaryform.FLASHmem

5、orycontentscanbechangedonlyincasewhereuserprogramisbeingchanged.PLCcontrollerswereusedearlierinsteadofFLASHmemoryandhavehadEPROMmemoryinsteadofFLASHmemorywhichhadtobeerasedwithUVlampandprogrammedonprogrammers.WiththeuseofFLASHtechnologythisprocesswasgreatlys

6、hortened.Reprogrammingaprogrammemoryisdonethroughaserialcableinaprogramforapplicationdevelopment.8.1.3　ProgrammingaPLCControllerPLCcontrollercanbereprogrammedthroughacomputer(usualway),butalsothroughmanualprogrammers(consoles).ThispracticallymeansthateachPLC

7、controllercanprogrammedthroughacomputerifyouhavethesoftwareneededforprogramming.Today’stransmissioncomputersareidealforreprogrammingaPLCcontrollerinfactoryitself.Thisisofgreatimportancetoindustry.Oncethesystemiscorrected,itisalsoimportanttoreadtherightprogra

8、mintoaPLCagain.ItisalsogoodtocheckfromtimetotimewhetherprograminaPLChasnotchanged.8.1.4　PowerSupplyElectricalsupplyisusedinbringingelectricalenergytocentralprocessingunit.MostPLCcontrollersworke