PLC英文文献翻译Word文档格式.docx

PLC英文文献翻译Word文档格式.docx

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slaborstrength,reducetheestablishmentonthepersonnel.Thetargetcontrolofthehardrealizationinmanycomplicatedproductionlines,wholeandexcellentturn,thebestdecisionetc.,well-trainedoperationwork,technicalpersonnelorexpert,governorbutcanjudgeandoperateeasily,canacquirethesatisfiedresult.Theresearchtargetoftheartificialintelligencemakesuseofthecalculatorexactlytocarryout,imitatetheseintelligencesbehavior,moderatingtheworkthroughperson'

sbrainandcalculators,withthemodethatperson'

smachinecombine,forresolvetheverycomplicatedproblemtolookforthebestpath

Wecomeinsightofthecontrolthatlinksaftertheelectricappliancesinvarioussituation,thatisalreadythethattimegenerationpast,nowofafteruseinthemoldaperhapssimpleequipmentsofgrass-rootscontrolthattheelectricappliancescandoforthelowlevelonly;

AndthePLCemergencealsobecametheepoch-makingtopic,addingthevividsoftwarecontrolthroughaveryandstablehardware,makingtheautomationheadforthenewhightide.

ThePLCbiggestcharacteristicsliein:

Theelectricalengineeringteacheralreadynolongerelectrichardwareuptoomanycalculationsofcost,aslongasordertheimportationthatthebuttonswitchortheimportationofthesensorsordertolinkthePLCupcansolveproblem,passtooutputtoordertheconjunctioncontactmachineorcontrolthestartequipmentsofthebigpoweraftertheelectricappliances,buttheexportationequipmentsdirectconjunctionofthesmallpowercan.

PLCinternalcontainmenthavetheCPUoftheCPU,andtaketohaveanI/Oforexpandofexteriortoconnectapeople'

saddressandsavingmachinethreebigpiecestoconstitute,CPUcoreisfromanormanyistiredtoaddthemachinetoconstitute,mathematicsthattheyhavethelogicoperationability,andcanreadtheproceduresavethecontentsofthemachinetodrivethehomologoussavingmachineandI/Ostoconnectafterpassthecalculation;

TheI/Oaddinnerpartistiredtheinputandoutputsystemofthemachineandexteriorlink,anddeposittherelateddataintotheproceduresavingmachineordatasavingmachine;

ThesavingmachinecandepositthedatathattheI/Oinputinthesavingmachine,andinworkadjustingtobecometiredtoaddthemachineandI/Ostoconnect,savingmachineseparatelysavingmachineRAMoftheproceduresavingmachineROManddates,theROMcandodepositofthedatapermanenceinthesavingmachine,butRAMonlyfortheCPUcomputesthetemporarycalculationusageofhourofbufferspace.

ThePLCanti-interferenceisveryandexcellent,ourrootneednotconcernitsservicelifeandtheworksituationbad,theseallproblemshavealreadynolongerbecomethetopicthatwefail,butstaytoourisaconcerntocometointernalresourcesofmakeuseofthePLCtostrengthenthecontrolabilityoftheequipmentsforus,makeourequipmentsmoregentle.

PLClanguageisnotweimagineofeditcollectedmaterialsthelanguageorlanguageofCstocarryonweavingthedistance,butthetrapezoiddiagramthattheadoptionisoriginalaftertheelectricappliancestocontrol,maketheelectricalengineeringteacherwhileweavingtowritetheprocedureveryeasycomprehendedthePLClanguage,andalotofnon-electricityprofessionalalsoveryquicklyknowandgodeepintotothePLC.

TounderstandthePLC'

scommunicationsversatility,let'

sfirstdefinethetermsusedindescribingthevarioussystems.

ASCII:

Thisstandsfor"

AmericanStandardCodeforInformationInterchange."

AsshowninFig.1,whentheletter"

A"

istransmitted,forinstance,it'

sautomaticallycodedas"

65"

bythesendingequipment.Thereceivingequipmenttranslatesthe"

backtotheletter"

A."

Thus,differentdevicescancommunicatewitheachotheraslongasbothuseASCIIcode.

ASCIImodule:

ThisintelligentPLCmoduleisusedforconnectingPLCstootherdevicesalsocapableofcommunicatingusingASCIIcodeasavehicle.

Bustopology:

Thisisalinearlocalareanetwork（LAN）arrangement,asshowninFig.2A,inwhichindividualnodesaretappedintoamaincommunicationscableatasinglepointandbroadcastmessages.Thesemessagestravelinbothdirectionsonthebusfromthepointofconnectionuntiltheyaredissipatedbyterminatorsateachendofthebus.

CPU:

centralprocessingunit,"

whichactuallyisthatpartofacomputer,PLC,orotherintelligentdevicewherearithmeticandlogicaloperationsareperformedandinstructionsaredecodedandexecuted.

Daisychain:

ThisisadescriptionoftheconnectionofindividualdevicesinaPLCnetwork,where,asshowninFig.3,eachdeviceisconnectedtothenextandcommunicationssignalspassfromoneunittothenextinasequentialfashion.

Distributedcontrol:

Thisisanautomationconceptinwhichportionsofanautomatedsystemarecontrolledbyseparatecontrollers,whicharelocatedincloseproximitytotheirareaofdirectcontrol（controlisdecentralizedandspreadoutoverthesystem）.

Hostcomputer:

Thisisacomputerthat'

susedtotransferdatato,orreceivedatafrom,aPLCinaPLC/computernetwork.

Intelligentdevice:

ThistermdescribesanydeviceequippedwithitsownCPU.

I/O:

inputsandoutputs,"

whicharemodulesthathandledatatothePLC（inputs）orsignalsfromthePLC（outputs）toanexternaldevice.

Kbps:

thousandbitspersecond,"

whichisarateofmeasureforelectronicdatatransfer.

Mbps:

millionbitspersecond."

Node:

Thistermisappliedtoanyoneofthepositionsorstationsinanetwork.Eachnodeincorporatesadevicethatcancommunicatewithallotherdevicesonthenetwork.

Protocol:

Thedefinitionofhowdataisarrangedandcodedfortransmissiononanetwork.

Ringtopology.ThisisaLANarrangement,asshowninFig.2C,inwhicheachnodeisconnectedtotwoothernodes,resultinginacontinuous,closed,circularpathorloopformessagestocirculate,usuallyinonedirection.Someringtopologieshaveaspecial"

loopback"

featurethatallowsthemtocontinuefunctioningevenifthemaincableissevered.

RS232.ThisisanIEEEstandardforserialcommunicationsthatdescribesspecificwiringconnections,voltagelevels,andotheroperatingparametersforelectronicdatacommunications.TherealsoareseveralotherRSstandardsdefined.

Serial:

Thisisanelectronicdatatransferschemeinwhichinformationistransmittedonebitatatime.

Serialport:

Thisthecommunicationsaccesspointonadevicethatissetupforserialcommunications.

Startopology.ThisisaLANarrangementinwhich,asshowninFig.2B,nodesareconnectedtooneanotherthroughacentralhub,whichcanbeactiveorpassive.Anactivehubperformsnetworkdutiessuchasmessageroutingandmaintenance.Apassivecentralhubsimplypassesthemessagealongtoallthenodesconnectedtoit.

Topology:

ThisrelatestoaspecificarrangementofnodesinaLANinrelationtooneanother.

Transparent:

Thistermdescribesautomaticeventsorprocessesbuiltintoasystemthatrequirenospecialprogrammingorpromptingfromanoperator.

Nowthatwe'

refamiliarwiththeseterms,let'

sseehowtheyareusedindescribingtheavailablePLCnetworkoptions.

PLCnetworkoptions

PLCnetworksprovideyouwithavarietyofnetworkingoptionstomeetspecificcontrolandcommunicationsrequirements.TypicaloptionsincluderemoteI/O,peer-to-peer,andhostcomputercommunications,aswellasLANs.Thesenetworkscanprovidereliableandcost-effectivecommunicationsbetweenasfewastwoorasmanyasseveralhundredPLCs,computers,andotherintelligentdevices.

ManyPLCvendorsofferproprietarynetworkingsystemsthatareuniqueandwillnotcommunicatewithanothermakeofPLC.Thisisbecauseofthedifferentcommunicationsprotocols,commandsequences,error-checkingschemes,andcommunicationsmediausedbyeachmanufacturer.

However,itispossibletomakedifferentPLCs"

talk"

tooneanother;

what'

srequiredisanASCIIinterfacefortheconnection（s）,alongwithconsiderableworkwithsoftware.

RemoteI/0systems

AremoteI/Oconfiguration,asshowninFig.4A,hastheactualinputsandoutputsatsomedistancefromthecontrollerandCPU.Thistypeofsystem,whichcanbedescribedasa"

master-and-slave"

configuration,allowsmanydistantdigitalandanalogpointstobecontrolledbyasinglePLC.Typically,remoteI/OsareconnectedtotheCPUviatwistedpairorfiberopticcables.

RemoteI/Oconfigurationscanbeextremelycost-effectivecontrolsolutionswhereonlyafewI/Opointsareneededinwidelyseparatedareas.Inthissituation,it'

snotalwaysnecessary,orpracticalforthatmatter,tohaveacontrollerateachsite.NorisitpracticaltoindividuallyhardwireeachI/OpointoverlongdistancesbacktotheCPU.Forexample,remoteI/Osystemscanbeusedinacquiringdatafromremoteplantorfacilitylocations.Informationsuchascycletimes,counts,durationorevents,etc.thencanbesentbacktothePLCformaintenanceandmanagementreporting.

InaremoteI/Oconfiguration,themastercontrollerpollstheslavedI/Oforitscurrent