运用PID控制英文文献.docx
- 文档编号:8208911
- 上传时间:2023-01-29
- 格式:DOCX
- 页数:27
- 大小:30.17KB
运用PID控制英文文献.docx
《运用PID控制英文文献.docx》由会员分享,可在线阅读,更多相关《运用PID控制英文文献.docx(27页珍藏版)》请在冰豆网上搜索。
运用PID控制英文文献
ApplicationNote83402
OriginalInstructions
PIDControl
WoodwardwishestothankandacknowledgeE.I.DuPontDeNemours&Company,Inc.forgranting
permissiontouseinformationpresentedinDuPont'sELIASInstrumentationTrainingProgrambookletinthis
Woodwardpublication.DuPont'scopyrighttotheabovementiondocumentisasfollows:
Copyright(1970)E.I.DuPontDeNemours&Company,Inc.
[WrittenbyLarryMcLeister]
WoodwardGovernorCompanyreservestherighttoupdateanyportionofthispublicationatanytime.Informationprovided
byWoodwardGovernorCompanyisbelievedtobecorrectandreliable.However,noresponsibilityisassumedbyWoodward
GovernorCompanyunlessotherwiseexpresslyundertaken.
©Woodward1992
AllRightsReserved
ApplicationNote83402PIDControl
Woodward1
Contents
CHAPTER1.INTRODUCTION.........................................................................2
ProcessControlLoop.............................................................................................2
AutomaticControl...................................................................................................3
ControlLoop...........................................................................................................4
ControlModes........................................................................................................4
ControlModes(CarAnalogy).................................................................................5
ProportionalControl................................................................................................5
Integral(Reset).......................................................................................................5
Derivative(PreactandRateTime).........................................................................5
ControlResponses.................................................................................................6
CHAPTER2.SINGLE-MODECONTROL.........................................................7
On-OffControl........................................................................................................7
ProportionalResponse...........................................................................................9
ProportionalGain(EffectofSettings).....................................................................9
Chapter2Summary.............................................................................................10
Chapter2ReviewQuestions................................................................................10
CHAPTER3.INTEGRALANDDERIVATIVECONTROL....................................11
Proportional+Integral(OpenLoop).....................................................................11
Integral..................................................................................................................12
Proportional+Integral(ClosedLoop)..................................................................13
Integral(EffectsofSettings).................................................................................14
DerivativeResponse............................................................................................15
Derivative(Minutes)..............................................................................................16
Proportional+Derivative(ClosedLoop)..............................................................17
Derivative(EffectsofSettings).............................................................................18
Proportional+Integral+Derivative(ClosedLoop)..............................................19
Chapter3Summary.............................................................................................19
Chapter3Review.................................................................................................20
CHAPTER4.TUNINGGUIDELINES..............................................................22
ControllerTuningMethodSample........................................................................24
ControllerFieldTuningGeneral...........................................................................25
ControllerFieldTuningProcedure.......................................................................27
PIDControlApplicationNote83402
2Woodward
Chapter1.
Introduction
ProcessControlLoop
Withthisblockdiagramofacontrolloop,thefollowingcanbeshown:
Thedashessurroundingthemeasurementtransmitter,thecontrolstation,and
thecontrollerindicatethe"local"controlstationsinceallpartsarewithinone
case.
Thedashessurroundingthecontrolstationandcontrolleronlyindicatethe
"remote"controlstation.
Thecontrollerinthiscasemaybemountedoneofthreeways:
onthecontrolstation
behindthecontrolpanelonarackwithothercontrollers
inthefieldonornearthecontrolvalve.
Itmayalsobeanintegralpartofthecontrolstationastheoneusedinthetraining
setup.
Bothtypesofcontrolstationswillhavesomewayofindicating(orrecording)the
processvariable,somemeansforadjustingthedesiredsetpoint,andameansfor
readingthecontrolleroutputtothecontrolvalve.The"local"controlstationmayor
maynothaveameansfor"manually"controllingthecontrolvalve.The"remote"
willalwayshavethisfacility.The"local"controlstationrequiresfrequentvisitation
todeterminequalityofcontrol.The"remote"stationiscentrallylocated,therefore
reducingtraveltimeandallowingside-by-sidecontrolqualityscanning.
ApplicationNote83402PIDControl
Woodward3
Thefunctionofeachblockofthediagramisasfollows:
1.Measurementtransmitter—measurestheprocessvariable(temperature,
pressure,level,flow,oranalysis)andconvertsthemeasurementtounits
usefultothecontroller(psig,kPa,etc)orsomeelectronicvaluesuchas4–20
mA.
2.Thecontrolstationprovidesfacilityforsettingthedesiredcontrolpoint,
readingthevalueofthemeasurement,transferringtheoperationfrommanual
toautomaticorautomatictomanual,andallowsmanualloadingofthecontrol
valve.
3.Thecontrollertakesthesetpointvalueofthecontrolstation,comparesits
valuetothemeasurementandreactstothedifferenceaccordingtothevalues
setoneachresponse,proportional,resetandderivative.
4.Theoutputsignalfromthecontrollerpositionsthecontrolvalve.
5.Theprocesschangesresultingfromthevalvechangesarefeltbythe
measurementandtheprocedurecontinues.
AutomaticControl
Thischartisasimplifiedformofthepreviouschart.Therearethreethingsthattake
place:
measurement
decision
action
Measurement,ofcourse,istheprocessvariabletobecontrolled.
Thedecisionisthecontroller.
Theactionisthecontrolvalve,sometimescalledthefinalelement.
Notethatthearrowsflowcontinuouslyasdoesthefunctionofanyclosedloop
controlsystem.Allsectionsofthecontrolsystemarecontinuouslyconnected,even
thoughactiondoesnottakeplaceunlessachangetakesplacethatresultsinthe
processvariablemeasureddeviatingfromthesetpoint(desiredcontrolpoint).
PIDControlApplicationNote83402
4Woodward
Tobreaktheconnectionbetweenanysectionoftheloopwouldresultinanopen
loopconfiguration.Ofcourse,theprocesswillthennotrespondtocontrolleraction.
However,aslaterchartswillshow,openloopconfigurationisauniquewayof
observingcontrolleractionsorresponsesonanindividualbasisandwithoutthe
interferingprocessresponse.
ControlLoop
Measurement(Transmitter)
1.Temperature
2.Pressure
3.Level
4.Flow
5.X-Analysis
Decision(Controller)
1.Setpointvs.measurement
2.Controllerresponse
Action(FinalElement)
1.Controlvalve
2.Pump
3.Rheostat
Controlloopcomponentsconsistofthoseshownontheabovechart.Asmentioned
earlier,threethingstakeplaceinaclosedloopcontrolsystem—Measurement,
Decision,Action,wheneverthesystemisinautomatic.Themeasurementsection
isconnecteddirectlytotheprocessandtransmitsthevariabletobecontrolledto
thecontrolstation,usuallysomedistanceaway.Thecontrolstation,which
technicallyincludesthecontroller,allowscomparisonbetweenthedesiredcontrol
point(setpoint)andthemeasuredcontrolpoint.Theamountofthedeviation,the
rateofthedeviationandthedurationofthedeviationallpredictcontrollerresponse
accordingtothecontroller'sgain,derivativeandresetsettings.
Theactionissimplytheresultofthecontrolleroutput.Itmaybesomethingother
thanacontrolvalve.
ControlModes
On-OffOr(Deadband)
Proportionalor(Prop_Gn)
Integralor(Int_Gn)
Derivativeor(S_D_R)
Asmentionedearlier,modesofcontrolrefertothevarioustypesofcontrol
available.Alsoitmustberememberedthatthetypeofcontrolshouldmatchthe
process.Forexample,on-offcontrolisquiteadequateforhomeheatingsystems,
butwouldbeveryunsatisfactoryinmostpetroleum/chemicalapplicationsbecause
ofitscycliccharacteristic.
Proportionalcontroleliminatesthecycliccharacteristicsoftheon-offmode.
IntegralandDerivativearerefinementsofandworkinconjunctionwithproportional
control.Specialstudiesofeachfollow.
ApplicationNote83402PIDControl
Woodward5
ControlModes(CarAnalogy)
ON-OFF—Onespeedwindshieldwiperinlightrain.
Onewaytodescribetermsnormallyunfamiliaristodrawananalogytosomething
whichisfamiliar.
TheanalogyhereforOn-Offcontrolisturningthewindshieldwiper"on"then"off".
Itsspeedisnotchanged.Itissimplyturned"on"foronewipe,thenturnedoff.
A
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 运用 PID 控制 英文 文献