外文翻译--PLC在冰蓄冷中央空调系统控制中的应用.doc

英文文献PLCintheicestoragecentralair-conditioningsystemofcontrol1IntroductionInPLCin30yearswhichdeveloped,itpassesthroughdevelopsunceasingly,alreadycouldunifysimulatesI/O,thenetworkcorrespondsaswellasusesnewprogrammingstandardlikeIEC61131-3.However,engineersonlymustusedigitalI/OandfewsimulationsI/Onumberaswellassimpleprogrammingskillonpotential80%industrialapplication.PLChasbeenwidelyusedinallindustrialsectors.Accordingto"TheUnitedStatesmarketinformation"WorldPLCandsoftwaremarketreport,in1995theglobalsoftwarePLCanditseconomiesofscaleofabout5billionUSdollars5.Aselectronictechnologyandthedevelopmentofcomputertechnology,Becauseusestraditionalthetooltobepossibletosolve80%industrialapplication,likethisintenselyneedstohavelowcostsimplePLC；ThuspromotedthelowcostminiaturePLCgrowth,ithastheusefultrapezoidallogicalprogrammingdigitalI/O.However,thishasalsocreatedthediscontinuityinthecontroltechnology,ontheonehand80%applicationneedtousethesimplelowcostcontroller,butontheotherhandother20%applicationthenhavesurpassedthefunctionwhichthetraditioncontrolsystemcanprovide.Engineerisdevelopingthese20%applicationtoneedtohavethehighercirculationspeed,theseniorcontrolalgorithm,themoresimulationsfunctionaswellascanwellandtheenterprisenetworkintegration.In80andthe90s,thesemustdevelop"20%application"engineershadconsideredusesPCintheindustrycontrol.PCprovidesthesoftwarefunctionmaycarryouttheseniortask,providestherichprogrammingandtheuserenvironment,andthePCCOTSpartenablescontrolengineerthetechnologywhichdevelopsunceasinglytouseinotherapplications.Thesetechnologiesincludingfloatingpointprocessor；HighspeedI/Omainline,likePCIandethernet；Fixeddatamemory；softwaredevelopmentkit.MoreoverPCalsocanprovidetheincomparableflexibility,highlyeffectivesoftwareaswellasseniorlowcosthardware.Icethermalstorageairconditioningisthecentralpowergridcouldberedundant-nighticeelectricityintheformofcoldstorage,inthedaytimepeakhoursofelectricitytoprovideair-conditioningservicesmeltingice.Asmostpartsofourcountryatnightthanduringthedaymuchlowerprice,usingicecoldstoragecentralair-conditioningcangreatlyreduceuseroperatingcosts.Icestoragecentralair-conditioningsystemconfigurationofequipmentthanconventionalairconditioningsystemtoincreasesome,requireahigherdegreeofautomation,butitautomaticallytomeettherequirementsoftheair-conditionedbuildingsalldayeverydayundertheconditionsoftheenergyhehasexhaustedall,thebiggestlimitstosaveoperatingcosts.thePLCfunctionsaregreatlyenhanced,withthefollowingcharacteristics:(1)highreliability.PLCbenefitedfromthehigh-reliabilityhardwareandsoftwareonaseriesofanti-jammingmeasuresandthecycleofitsspecialscanningmethodsofwork.(2)withrichI/Ointerfacemodule.PLCfordifferentindustrialfieldsignalandthecorrespondingI/Omodulesandindustrialdevicesorequipmentatthesceneofadirectconnection.Inadditiontoimprovingperformance,italsohasavarietyofman-machinedialogueinterfacemodulestotheindustrialcompositionoflocalareanetworks,italsomultiplecommunicationsnetworkinterfacemodule.(3)modularstructure.Tomeettheneedsofvariousindustrialcontrol,inadditiontoasmallPLCunit,thevastmajorityofPLCaremodularstructure.PLCvariouscomponents,includingtheCPU,powersupply,I/O,etc.ismodularindesignfromtherackandcableswillconnecteachmodule,thesystemssizeandfunctioninaccordancewiththeneedsofusersofitsownportfolio.(4)easytolearnprogramming.MostofthePLCprogrammingrelaycontrolcircuitsimilartotheladderdiagramform,theuser,donothavecomputerexpertise,itiseasytogeneralengineeringandtechnicalpersonnelunderstandandmaster.(5)Installationissimpleandeasymaintenance.PLCdoesnotrequirespecializedequipmentroominavarietyofindustrialenvironmentscanbedirectlyrun.Variousmodulesarerunandfaultindicationdevices,user-friendlyunderstandingoftheoperationandfindfault.Themodularstructure,soanyfailureofamodule,userscanreplacethemodule,allowingthesystemtorapidlyresumeoperation.Second,thecharacteristicsandApplicationofindustrialPC2ControlsystemThecontrolsystemconsistsofthecrew(FloorControlWorkstation)andPC(centralmanagementworkstation),withthecrewusingprogrammablelogiccontroller(PLC)withthetouchscreen,PCusingindustrial-gradecomputersandprinters,systemconfigurationnecessaryiftheannexcommunicationsequipmentinterfaces,networkinterfacecards,modemsandsoon,toachievetheparametersofthestoragesystemandintelligentautomaticoperation.Underthecrewatthesceneandtouch-screensystemscancontrol,parametersettingsanddata.PCremotemanagementandprint,itcontainsthecrewandallofthefeaturestouchscreen.Followingthesystemasawholecrewofindustrialprogrammablelogiccontrollerasthecore,toachieveautomaticcontrol.Controlequipmentanddevicesincluding:detectionsensorcomponents,electricvalves,converter,etc.Underthe2.1-Systems(Regionalworkstations)2.1.1TP21touchscreenTP27usedasacolortouch-screenoperatorpanel,completelyreplaceconventionalbutton,lightsdevice,thecontrolcabinetinterviewedmoretidy.Moreover,TP27touchscreenatthesceneshowedthatthestatecanberealized,systemsettings,modeselection,parametersetting,faultrecording,recordload,time-of-day,real-timedata,loadcurveandreportingstatistics,andotherfunctions,Chineseintuitiveandfriendlyuserinterface.2.1.2SIEMENSPLCSIMATICS7-300SeriesPLCappliedtoallwalksoflife,allkindsofoccasionsinthedetection,monitoringandcontrolautomation,itspowerfulfeaturestobothoperateindependently,orlinkedtoanetworkabletoachievecomplexcontrolfunctions.Theproductfeaturesphotoelectricisolation,andhighelectromagneticcompatibility；highindustrialapplicability,allowingtheambienttemperatureof60；hasastronganti-jammingandanti-vibrationandimpactresistance,intheharshenvironmentoftheworkhasbeenwidelyapplications.IalsomeansfreedomofcommunicationsS7-300PLC,averyuniquefeatures,itmakesS7-300PLCwithanycommunicationprotocolcanopenotherequipment,communicationscontroller,orPLCS7-300canbedefinedbytheusersthemselvescommunicationsprotocols(forexampleASCIIprotocol),baudrateof1.5Mbit/s(adjustable).Thusthescopeofthecommunicationscanbegreatlyincreased,thecontrolsystemconfigurationmoreflexibleandconvenient.Anyserialinterfacewithperipherals,suchas:printerorbarcodereaders,thedrive,amodem(Modem),theupperPCcanbeconnectedtothemachine.Userscanprogramtodevelopcommunicationprotocoltoexchangedata(suchas:ASCIIcharactercode),RS232interfacewiththeequipmentavailablePC/PPIfreecablelinkingcommunicationscommunication.1.ChipandChipHolderslntegratedCircuisareusuallycalledIcsorchips.Thayarecomplexcircuits,whichhavebennetchedontotinychipsofsemiconductor(silicon).Thechipispackagedinaplasticholderwithpinsspacedona0.1(2.54mm)grid,whichwillfittheholesonstipboard.Veryfinewiresinisdethepackagelinkthechiptothepins.2.PinnumbersThepinsarenumberedanti-clockwisearoundtheIC(chip)startingnearthenotchordot.Itshowsthenumberingfor8-pinand14-pinIcs,buttheprincipleisthesameforallsizes.3.Chipholders(DILsockets)ICs(chip)areeasilydamagededbyheatwhensolderingandtheirshortpinscannotbeprotectedwithaheatsink.Insteadweuseachipholder,strictlycalledaDILsocket(DIL=DualIn-Line),whichcanbesafelysolderedontothecircuitboard.Thechipispushedintotheholderwhenallsoldingiscomplete.Chipholdersareonlyneddedwhensoldingsotheyarenotusedonbreaboards.Commerciallyproducedcircuitboardsoftenhavechipssoldereddirectlytotheboardwithoutachipholder,usuallythisisdonebyamachinewhichisabletoworkveryquickly.Pleasedonnotattemptodothisyourselfbecauseyouarelikelytodestorythechipanditwillbedifferenttoremovewithoutdamagebyde-soldering.4.RemovingachipfromitsholderIfyouneedtoremoveachipitcanbegentlyprizedoutoftheholderwithasmallflat-bladescrewdriver.Carefullyleverupeachendbyinsertingthescrewdriverbladebetweenthechipanditsholderandgentlytwistingthescrewdrive.Takecaretostatreliftingatbothendsbeforeyouattempttoremovethechip,otherwiseyouwillbendandpossiblybreakthepins.5,BipolarIntegratedCircuitsMOSIntegratedCircuitsHistorically,bipolarIntegratedCircuitsusedtobemuchmorepopularthanMOSIntegratedCircuits,particularlyforsmall-sacelogicCircuits.Thereweretwomajorreasonsforthis:first,bipolar-junctiontransistorsoriginallycouldbemanufacturedmorereliablythanMOStransistors,andsecond,theywerefaster,AsthereliabitityofMOStransistorsimproved,andasintegratedCircuitsbecamemorecomplex,whichmadethelowerpowerandsmallsizeofMOSlogicmoreimportant,thepopularityofBJTlogicdecreased,however,BJTtechnologyisstillpopularforthehighestfrequencylogiccircuits.WhenthePCoffline,underthecontrolofthenextcrew,theentiresystemcanoperatenormally.2.2PCSystem(centralmanagementworkstation)2.2.1PCPCthatisbycontrolcentre,mainlybythePCandlaserprintercomponents,SIMATICWINCCsoftwareplatformusedbytheentireChineseuserinterface,friendlyman-machinedialogue.Managementandoperation,canbeobservedbyPC-displayallkindsofinformationtounderstandthecurrentandpreviouscontrolledtheentireicestoragesystemandtheoperationofallparameters,andequipmentthroughthemouseprintmanagementandtheimplementationoftasks.2.2.2WINCCsoftwareplatformWINCCsoftwareinthefieldofautomationcanbeusedforalloperatorcontrolandmonitoringtasks.Processcontrolcanbeintheeventsclearlyshow,canshowthatthecurrentstaterecordsinaccordancewiththeorder,alltherecordeddatacanbedisplayedorselectsummaryform,ormayberequiredforediting,andoutputprintstatementsandtrends.WINCCabletocontroltheprocessofthecriticalearlystagesofthereport,andthesignalcanbedisplayedonthescreen,andcanalsousevoicedemonstrated.Itsupporttheuseofon-linehelpandoperationalguidelinestoeliminatefault.WINCCaspecializedworkstationscanbeusedtocontroltheprocesssothattheimportantprocessinformationisnotshielded.-Aidedsoftwarestrategyassuranceprocessisnotillegalaccess,andprovidefortheindustrialenvironmentnowrongintheoperation.WINCCisMICRSOFTWINDOWS98orWINDOWSNT4.0operatingsystem,runningonaPCobject-orientedclass32applications,throughWindowsOLEandODBCstandardmechanism,asanidealcommunicationspartnerstoenterWINDOWSworld,andthereforecanbeeasilyWINCCtointegrateacompany-widedataprocessingsystem.3Icestoragesystemcontrol3.1Controlobjectives,scopeandmainlycontrolledequipmentStorageControlSystemcontrolpurposes:Throughtherefrigerationhost,icestoragedevices,plateheatexchanger,thesystempumps,coolingtowers,pipingsystemregulatingvalvecontrol,icestoragesystemadjustmentofthestatusoftheoperationmode,inthemosteconomicalcircumstancestotheterminaltoprovideastablewatersupplytemperature.Atthesametime,improvethelevelofautomation,improvethemanagementefficiencyandreducelaborintensitymanagement.Controloftheicestoragesystem,includingtheentirestateoftheparameters,equipmentstatusandcontrol,themaincontrolequipment:duplexstatusconsole,electricvalves,coolingtowers,coolingwaterpumps,icestoragedevices,theprimaryglycolpump,plateheatexchanger,sub-glycolpumps.3.2ControlControlfunctionsincludetheicestoragesystemstability,andeconomicoperationofthe