外文文献原稿及译文.docx

外文文献原稿及译文.docx

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外文文献原稿及译文

外文文献原稿和译文

原稿

AboutProgrammableLogiccontrollers（PLCs）

PLCs（programmablecontroller）isusedinavarietyofautomaticcontrolsystemandprocesscontrolhub.Theycontainmultipleinputandoutput,inputandoutputisusedtotransistorsandothercircuit,analogswitchandrelaytocontroltheequipment.PLCsoftwareinterface,standardcalculatorinterface,specializedlanguageprogrammingandnetworkequipment.

ProgrammablelogiccontrollerI/Ochannelrulesincludingallinputoutputcontactandcontact,toexpandcapacityandthelargestnumberofchannels.Contactnumberisthesumofinputandoutputpoints.PLCcanspecifyanycombinationofthesevalues.Extensionunitscanbestackorconnectedtoeachothertoincreasethetotalcontrol.Thelargestnumberofchannelsareinanextensionsystem,thetotalnumberofmaximuminputandoutputchannels.PLCsystemrulesincludescanningtime,numberofinstructions,datastorageandstorageprogram.ScantimeisusedtomonitorinputandoutputmoduleofPLCneedtime.StandardoperationinstructionisusedinPLCsoftware.Datastorageistheabilitytostoredata.Programmemoryistheabilitytocontrolsoftware.

UsedforprogrammablecontrollerinputdevicesincludingDC,AC,intermediaterelay,thermocouple,RTD,frequencyorpulse,transistorsandinterruptsignalinput;OutputdevicesincludeDC,AC,intermediaterelay,frequencyorpulse,transistor,three-terminaltwo-waythyristorswitchcomponents;PLCprogrammingequipmentincludingcontrolpanel,handleandcomputer.

Programmablecontrolisusedtocontrolavarietyofsoftwareprogramminglanguage.Theselanguagesincludingiec61131-3,sequentialtable（SFC）,actionblockdiagram（FBD）,ladderdiagram（LD）,andthestructureofthetext（ST）,instructionsequences（IL）,relayladderdiagram（RIL）,flowcharts,ClanguageandBasiclanguage.Iec61131-3programmingenvironmentcansupportfivelanguages,withinternationalstandardstoregulate,SFC,respectively,FBD,LD,STandIL.Thisallowsmorevendorcompatibilityandavarietyoflanguages.SFCisakindofgraphlanguage,itprovidestheprogramminginordertocooperate,cansupporttheorderselectionandtiedforchoice,tochoosebetweenthem.RuntimeFBDwithabig,establishedthecomplicatedprocess,intheformofgraphs.Standardmathematicalandlogicaloperationcanbecombinedwithuserinteractionandinterfaceoperation.LDissuitablefordiscretecontrolandinterlocklogicdiagramlanguage.ItisfullycompatiblewithFBDondiscretecontrol.STisakindoftextlanguage,usedforcomplexmathematicalandcomputationalprocess,languageisnotapplicabletochart.ILissimilartothecombinationofcodinglow-levellanguages.Itisusedinrelativelysimplelogicalinstructions.Relayladderdiagramandladderdiagramisusedforprogrammablecontrollerisanimportantprogramminglanguage.Ladderdiagramprogrammingisdesignedtorelaylogicdiagramrepresentationoftheprogram.Flowchartisagraphiclanguage,foruseinacontrolleroroperationsdescribedintheorderofapplicationsoftware,itisusedtoestablishastandardcomponentofrecycledruntime.Clanguageisahigh-levelprogramminglanguage,suitableforprocessingthemostcomplicatedcalculation,acontinuousdataacquisitiontask.IttypicallyruninPCdebugging.BASIClanguageisusedtohandlethenumberofconsecutivedataacquisitionandinterfaceoperationofhigh-levellanguage.

Programmablecontrolleralsospecificationofmanycomputerinterfaceequipment,networkrulesandcharacteristics.PLCenergyequipmentandrunningenvironmentisalsoveryimportant.

Thedevelopmenthistoryofprogrammablecontroller

In1968,generalmotors（GM）,accordingtotheneedsofthedevelopmentofthemarketsituationandputforwardthe"manyvarieties,smallbatch,newcarbrandmodel"strategy.Toimplementthisstrategy,relyingontheoriginalindustrialcontroldeviceobviouslynot,andtheremustbeakindofnewindustrialcontroldevice,itcanbewiththechangeoftheproducts,flexibleandeasilychangecontrolschemetodifficulttomeetthedifferentrequirementsofcontrol.

In1969,thefamousAmericandigitalequipmentcorporation（DEC）accordingtothefunctionrequirementsofGM,developedthenewindustrialcontroldevice,andtheGMofavehicletorunautomatedproductionlineforthefirsttimetosucceed.Accordingtothisnewtypeofindustrialcontroldevicescanbeprogrammedtochangecontrolschemethischaracteristic,andthesituationofthespecializedforLogiccontrol,saysthenewindustrialcontroldevicefortheProgrammablecontrol（ProgrammableLogicController）,hereinafterreferredtoasPLC.

From1968tonow,thePLChasexperiencedfourgeneration:

mostofthefirstgenerationofPLCwithamachinedevelopment,withthecorememorystorage,onlythelogiccontrolfunction.InthesecondgenerationofPLCproductsfor8-bitmicroprocessorandsemiconductormemory,PLCproductseriation.ThethirdgenerationofPLCproductwithhighperformancemicroprocessorandchipisusedingreatquantitiesinthePLCCPU,PLCspeedgreatlyimproved,thusenablingittodevelopinthedirectionofmulti-functioncommunicationsandnetworking.ThefourthgenerationofPLCproductsnotonlycomprehensiveuse16-bitand32-bithigh-performancemicroprocessors,high-performanceslicemicrocontrollerprocessor,RISC（Reducedinstructionsetcomputer）ReducedinstructionsystemCPUandotheradvancedCPU,andmorethanoneprocessorinaPLCconfiguration,multi-channelprocessing.Alsoproducedalargenumberofembeddedmicroprocessormodule,onlymakesthefourthgenerationofPLCproducthasthefunctionoflogicalcontrol,processcontrol,motioncontrol,datacontrol,networkedcontrolfunctionsreallyworthyofthenameofmulti-functionalcontroller.Atthesametime,thePLCnetworkcomposedofPLChasalsobeenrapiddevelopment.PLCandindustrialcontrolofPLCnetworkinfactoryenterprisesbecomethepreferreddevice,composedofPLCmulti-stagedistributedPLCnetworkbecomeindispensablefundamentalpartofCIMSsystem.PeoplespokehighlyoftheimportanceofPLCanditsnetwork,itisoneofthethreepillarsofmodern.

Selectingmachinemodel

MarketpopularPLCproductsmanufacturerinChinawiththefollowingcompanies:

（1）schneidercompany,includingtheintroductionofearlyfromModiconcompanybythetianjininstrumentinstrumentandmeterplantproducts,productsarenowQuantum,PremiumandMomentum;

（2）rockwellcompany（includingABcompany）PLCproducts,productsarenowSLCandMicroLogixControlLogixetc.

（3）ofSiemensPLCproducts,productsarenow400/300/S7-200series;

（4）gePLCproducts;

（5）thecompany'sproductssuchasomron,mitsubishi,Fuji,panasonic,oneofthemostpopularisthemitsubishiFXseries.

ThebasicprincipleofPLCselectionis:

intheinput/outputquantitymeettherequirementsunderthepremiseofshouldchoosethemostreliable,maintenance,andusethemostconvenientandcost-effectiveoptimalproducts.

SelectingI/O

PLCisanindustrialcontrolsystem,thecontrolobjectisindustrialproductionequipmentortheproductionprocessofindustrialproducts,workingenvironmentistheindustrialproductionfield.ItconnectstheindustrialproductionprocessisachievedbyI/Ointerfacemodule.PLChasalotofI/Ointerfacemoduleincludingswitchinputmodule,theswitchoutputmodule,analoginputmoduleandanalogoutputmoduleandspecialmodule,weshoulduseaccordingtothecharacteristicsoftheirimplementationoptions.

（1）determinethenumberofinput/output

Accordingtotherequirementsofthecontrolsystem,determinethenumberofinput/outputrequired,shouldincreasethesparequantityof10%20%,inordertoincreasecontrolfunctioninanytime.

（2）theswitchquantityinput/output

Switchinput/outputinterfaceandcantakethesignalsfromthesensorsandswitchesandcontrolequipment.Atypical24-240-vacinput/outputsignals,5-240-vdcinput/outputsignals.

（3）theanaloginput/output

Analoginput/outputinterfacecanacceptthesignalgeneratedbythesensor.Theseinterfacescanbeusedtomeasureturnoverrate,temperatureandpressure,andthustocontrolthevoltageorcurrentoutputdevice.Rangefortheseinterfaces-10-10v,+0to10v,4-20ma,or10to50ma.

SomemanufacturersonthePLCdesignspecialdedicatedanaloginterface,soitcanreceivelowlevelsignal.Ingeneral,thisinterfacemodulecanbeusedtoreceivedifferenttypesofthermocoupleandRTDmixedsignal.

（4）specialfunctioninput/output

WhenselectingaPLC,usermayfacedsomespecialtypesofinput/outputandsomebecauseofthelocationofthelimitedinput/outputandfastresponseandfrequencyproblemcausedbythenonstandardinput/output.Now,theusershouldconsiderwhethertoacceptbythemarketormanufacturerstoprovideaspecialmodule,throughadedicatedpartofthemoduleanddisposedata,soastoreducetheuseoftheCPU,improvetheefficiencyofthetaskprocessing,tominimizefailurecausedbyhighlimitcontrol.

PLCstatus

InaPLC,thelackofkeyboardandotherinputandoutputdevicesisaveryworthyofattention.InPLCfrontusuallyhaveacertainamountofstatusindicators.Usuallyindicatesthat:

Thestart-up-aslongasthePLCcharged,itwillbestarted.

Programisrunning-thiswillindicatewhetherrunningorifnoprogramisrunning.

Errordisplay-whenPLChasalargehardwareorsoftwareerrors,itwillbedisplayed.

Theselightsareusuallyusedfordebugging.AcertainnumberofbuttonwillalsobeprovidedtothePLChardware.Themostcommonbuttonisarun/programmingselectionswitch,wheninkeepingthestate,itwillbetransferredtotheprogramming;Whentheproductionstatu