PLC在加热炉温控制系统中的应用外文翻译Word下载.docx
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本科毕业论文(设计)
开题报告
论文题目:
PLC在加热炉温控制系统中的应用
学生姓名:
学号:
专业:
指导教师:
2012年11月
外文翻译
译文:
PLC Temperature Control of an Electric Heating Furnace
Abstract:
This paper introduces a temperature control system for fin electric heating fumace based on the PLC technology and the electronic rectifier technology.y.The hardware and software of the system are also outlined.
Keyword:
programmable logic controller;
heating furnace;
PID
1Introduction
Hotstoveusingsimplebittypeconstanttemperaturecontrolmethod,temperaturecontrolprecisionisnothigh,thetemperaturecontrolisofunidirectionalrising,largeinertia,largetimedelay,time-varyingcharacteristics,andtheheating,thermalinsulationisdependentontheresistancewireheating,cooling,relyonthenaturalenvironmentforcoolingoraddfurnacematerial,oncetheovershootisdifficulttousecontrolmeanstobringthetemperature.Accordingtomathematicalmodelofcontrolledobjectisdifficulttodeterminepreciselythecharacteristics,thesystemconsistsofPLCasthecorecontroller,accordingtothetemperaturechangeofthePIDcontroller,thecollectionoftemperaturedata,andthenthroughthePLCoutputcontrol,regulatingthyristorconduction,toachieveaccuratecontroloftemperature.Inthispaper,thecontrolobjectiscommonlyusedinthemetallurgicalindustryinHX1typeelectricheatingfurnace,furnacetemperaturefor20-600°
2Systemstructure
.ThehardwaredeviceismainlycomposedofPC,programmablecontroller,temperaturesensor,temperaturetransmitter,solidstaterelaysandelectricheatingfurnace.Asshowninfigure1.
Fig1theblockdiagramofthecontrolsystemofheatingfurnace
Thecontrolsystemofcontrolinformationanddatainformationinthecomputercentralizedmanagement,allocation,makethesystemmoresimple,effective,theusercanbrowse,printingvariousfielddata,statements,andalsotocontrolthespotoperationcontrol.Thetemperaturecontrolsystemofsingleloopcontrolsystem,bytheMitsubishiCoFx2NseriesPLCasthecorecomponent,temperaturedetectionusingplatinumthermalresistanceKrlOO,usedforreal-timedetectionoftemperatureoutput,theRTDmoduleisplacedafterthebigintoanaloginputmoduleFx2N4AD,convertedintodigitalquantity,theuserprocedure,callthePLCinternalPIDthecontrolalgorithm,aPIDoperationalvalues,thevaluesareconvertedintotimevalue,toatime-varyingPWMwavetocontrolzerovoltagetriggersolidstaterelaySSR,toregulatetheelectricheatingwireworkingcurrent,torealizetheheatingfurnacetemperaturecontrolsystem.ThesoftwarepartWindowsXPastheoperatingsystem,theindustrialcontrolconfigurationsoftwareMCGSastheapplicationserverplatform.BetweencomputerandPLCthroughtheMPIportconnection,therealizationofPCandPLCcommunication.Bythecomputertocompletethetemperaturesetting,temperatureandvariouscontrolparametersreal-timemonitoring.
3PIDcontrolalgorithmtoachievethePLC
UsingprogrammablecontrollerforanalogPIDcontrol,youcanusethePIDprocesscontrolmodule,andthismoduleisexpensive,economyispoor.ThesystemusesthePIDfunctioninstruction,whenP1Dfunctioninstructionwiththeanalogquantitywhenusedtogether,notonlycanbesimilartothePIDprocesscontrolmodule,andtheeconomyisgood.Duetotheheatingfurnaceislargedelay,largeinertialinkcontrolobject,thesystemadoptstheintegralseparationPIDalgorithmandBangpositionBangcontrolmethods,namelyatthebeginningoftheprocess,theCambodianguitarorsubstantiallyincreasethesetvalue,byusingtheBangBangcontrol,preventexcessivedeviation,integralaccumulation,thesystemcausedbylargerovershootevenoscillation,sothatthesystemstabilitydecline.Andtotheprocessofthelate,whenthedeviationtothespecifiedrange,increasetheintegralaction,inordertoimprovethecontrolprecision.Intheactualprocessofdebugging,afterseveralrevisionsofcontrolparameters,canachievegoodcontrolparameters,toachievetherequiredprecision.
PLCmainprogramflowdiagramasshowninfigure2,
Fig2
ThePIDalgorithmprogramflowdiagramasshowninFigure3
Fig3
4PIDalgorithmforconvertingthePWMwaveoutput
Theadjustmentofthetemperaturecontrolisthecontrolofthebidirectionalthyristorturn-ontime,therebychangingtheheatingwireheatingpowertorealizethetemperaturecontrol.Firstofall,thePIDoperationresultisconvertedintoaninternaltimertimingvalue,todeterminethedelaytime.Thissystemadoptsthepowerregulatingcircuit,controlapowercycleintheactualconductiontime,theoutputMVisconvertedtoatimevaluemode.Duetotheuseofaninternaltimertimebasefor10ms,T200,andbecausethepowercycleselectedforTz,sotheactualheating