PLCCharacteristicPLCEnglishfulltitleProgrammableLogicController,Chinesefulltitleastheprogrammablelogicalcontroller,thedefinitionis:Onekindofdigitaloperationoperationselectronicsystem,fordesignsspeciallyintheindustryenvironmentapplication.Itusesakindofprogrammablememory,usesinitsinternallystoredprogram,theactuatinglogicoperation,thesequentialcontrol,fixedtime,countingandarithmeticoperationandsoonfaceusersinstruction,andthroughdigitaleithersimulationtypeinput/outputcontroleachtypemachineryorproductionprocess.PLCcharacteristic:2.1reliabilityishigh,antijammingability.dependingonthenatureistheelectriccontrolequipmentsessentialperformance.BecausePLCusesthemodernlargescaleintegratedcircuittechnology,usedthestricttechniqueofproductionmanufacture,theinternalcircuithasadoptedtheadvancedantijammingtechnology,hadtheveryhighreliability.ForexampletheMitsubishiCorporationproducesFseriesPLCmeantimebetweenfailurereachesashighasfor300,000hours.SomeuseredundancyCPUPLCaveragetrouble-freeoperatingtimeislonger.FromthePLCoutsidetheaircraftelectriccircuit,usesthePLCconstitutioncontrolsystem,compareswiththesamelevelscalefollowingtheelectricalpick-offsystem,theelectricalwiringandtheswitchcontactreducedtoseveralhundredsevenseveralthousands1,thebreakdownalsogreatlyreduces.Inaddition,PLChasthehardwarefaultself-measuringability,presentswhenthebreakdownmaysendoutthewarninginformationpromptly.Intheapplicationsoftware,theapplicationmayalsoenrolltheperipherycomponentsbreakdownfromthediagnosticprogram,causesinthesystemalsoobtainsthebreakdownbesidesthePLCelectriccircuitandtheequipmentfromthediagnosisprotection.Thus,theoverallsystemhastheextremelyhighreliabilityalsonottofeelstrange.2.2necessarycomplete,thefunctionisperfect,serviceable.PLCdevelopstoday,hadalreadyformedthelarge,mediumandsmalleachscaleserializedproduct.Mayuseineachscaletheindustrialcontrolsituation.Besidesthelogicalprocessingfunction,modernPLCmostlyhastheconsummationdataoperationability,mayuseineachkindofnumericalcontroldomain.InrecentyearsthePLCfunctionunitemergedmassively,causesPLCtoseepthepositioncontrol,thetemperaturecontrol,CNCandsooneachindustrialcontrol.InadditionthePLCtrafficcapacitysenhancementandtheman-machinecontactsurfacetechnologysdevelopment,usesPLCtocomposeeachkindofcontrolsystembecomesveryeasy.2.3easytostudyeasilytouse,thedepthiswelcometheengineersandtechnicians.PLCtakesthegeneralindustrialcontrolcomputer,isfacesIndustrialandminingestablishmentslabortocontroltheequipment.Itsconnectioniseasy,theprogramminglanguageacceptseasyfortheengineersandtechnicians.Thetrapezoidalchartlanguagesgraphicssymbolandtheturnofexpressionandtherelaycircuitdiagramisquiteclose,onlyusesPLCthefewswitchquantitylogicalcontrolinstructiontobepossibletorealizetherelayelectriccircuitsfunctionconveniently.Fornotthefamiliarelectroniccircuit,didnotunderstandthecomputerprincipleandtheassemblylanguagepersonusesthecomputertobeengagedintheindustrialcontroltoopengateoftheconvenience.the2.4systemsdesign,theconstructionworkloadaresmall,maintainconveniently,easytotransform.PLCreplacesthewiringlogicwiththestoredlogic,reducedthecontroldeviceexteriorwiringgreatly,causescontrolsystemdesignandtheconstructioncycleisthereductiongreatly,simultaneouslymaintainsalsobecomeseasy.Causestheidenticalequipmentpossiblytobecomemoreimportantlyafterthealterprocedurechangeproductionprocess.Thisverysuitablemulti-varieties,smallbatchproductionsituation.the2.5volumeissmall,theweightislight,theenergyconsumptionislow.TakesubminiaturePLCastheexample,recentlyproducedthevarietybasesizeissmallerthan100mm,theweightissmallerthan150g,thepowerlossonlycountsthetile.Becausethevolumesmallveryeasytoloadinthemachinery,realizestheintegrationofmachineryidealcontroldevice.Sincelong,PLCisintheindustrialautomationcontroldomainthroughoutthemainbattlefield,hasprovidedtheveryreliablecontrolapplicationforvariousautomationcontroldevice.Itcanprovidesafereliableandthequiteperfectsolutionfortheautomatedcontrolapplication,suitsinthecurrentIndustrialenterprisetotheautomatedneed.Sincethe1980s,asaresultofthecomputertechnologyandmicroelectronictechnologysrapidlyexpand,theenormousimpetusPLCdevelopment,thePLCfunctionwhichcausedstrengtheneddaybyday.IfPLCmaycarryonthesimulationquantitycontrol,thepositioncontrolandthePIDcontrolandsoon,easytorealizetheflexiblemanufacturesystem.Thelong-distancecorrespondencefunctionrealizescausesPLCevenmorepowerful.Atpresent,intheadvancedcountries,PLChasbecometheindustrialcontrolthestandardequipment,hascoveredallIndustrialenterprisenearlyusingthesurface.PLCisonekindofsolidstateelectronicinstallation,itusestheprocedurewhichstorestocontrolmachinesmovementorthecraftworkingprocedure.PLCisusesfortosubstitutefortraditionaltheblack-whitecontrol,compareswithit,PLCismoreoutstandingthanintheperformancetheblack-whitecontrollogic,thereliabilityisspeciallyhigh,thedesignconstructioncycleisshort,thedebuggingrevises,moreoverthevolumetobesmallconveniently,thepowerlossislow,theusemaintenanceisconvenient.Therefore,thisarticlehasstudiedbasedontheprogrammablecontroller(PLC)electricmotorsynthesismonitoringandprotectivesystemsmethod.Makestheelectricmotormovementthethree-phaseasynchronousmachine.Becausethethree-phaseasynchronousmotorrotorsrotationalspeedislowerthantherotaryfieldtherotationalspeed,therotorwindinghastherelativemotionwiththemagneticfield,buttheinducedemfandtheelectriccurrent,andhavetheelectromagnetismtorquewiththemagneticfieldinteraction,realizestheenergyevolution.Compareswiththesingle-phaseasynchronousmotor,thethree-phaseasynchronousmotorperformancecharacteristicisgood,andmaysaveeachmaterial.Thecrookedsubstructuresdifference,thethree-phaseasynchronousmotormaydivideintothecagetypeandwindthreadthetypetwokinds.Thecagetyperotorsasynchronousmotorstructureissimple,themovementisreliable,theweightislight,thepricewascheap,obtainedthewidespreadapplication,itsmajorobjectwasthevelocitymodulationdifficulty.Theregulatingrheostatresistancemayimproveelectricmotorsstartingabilityandadjustelectricmotorsrotationalspeed.Thethree-phaseasynchronousmotorwillchangethevoltagenottochangetherotationalspeed,commonlyusedchangesthenumberofpolepairs.Changesthethree-phasepowersourcesfrequency.Changesliding,abovetwocommonvelocitymodulationmethod.Thechangenumberofpolepairsneedstolookthattheelectricalmachineryiswhetherappropriate,ifinwerediodeselectricalmachinerycannotchange,afteranotherwasthechange,itsoutputcorrespondinglywillalsochange,wasnotthesteplesschange.Thechangeslidingusescopespeaksthedot,onlyuses,incomparesthehighefficiencytowindthreadontheelectricalmachinery,thesmallelectricalmachinerysrotordoesnotwindthread,changedtherotorinducedemfthefrequencytochangeelectricmotorsrotationalspeed.Moreoverthesimplethemeansarechangeintotheelectricmotortheslipperydifferenceelectricalmachinery,mightthesteplessspeedregulation,becauseinthevelocitymodulationprocess,theelectricalmachineryrotationalspeedwasinvariable,likethisoutputtherotationalspeedtobepossibletomovehasnotaffectedverylowlytotheelectricalmachinery.PLC的特點PLC英文全稱ProgrammableLogicController,中文全稱為可編程邏輯控制器，定義是:一種數(shù)字運算操作的電子系統(tǒng)，專為在工業(yè)環(huán)境應(yīng)用而設(shè)計的。它采用一類可編程的存儲器，用于其內(nèi)部存儲程序，執(zhí)