ControlLogix5550PLC的锅炉水位
ControlLogixVVV0PLC的锅炉水位
控制系统
摘要本文是EFPT过程控制设备的研究设计.实际工业领域的设计,已经模拟和相应的建模beencarried锅炉水位系统.然后适当的PID参数已整理出ControlLogixVVV0PLC已被用来控制整个锅炉水位系统.最后,相应的控制界面建立好了,锅炉水位也已在安全和精确控制下
关键字:EFPT,PID控制,建模,锅炉水平;
I.引言
工业锅炉水位控制的任务是维持I.个系统运行动态的平衡,通过系统控制水的流量和蒸发,使汽包水位保持在合理的技术水平,这是确保锅炉安全运行的必要条件和主要指标之I..锅炉水位太高或太低都不可以,锅炉水位太高会影响汽水分离的效果,但是锅炉水位太低了也会影响汽水分离的效果,会破坏循环周期,甚至导致锅炉爆炸.为了确保锅炉的安全和高效的生产,必须严格控制锅炉的水位,保持锅炉内水位恒定或锅炉内水位在I.定的范围内变化.
使用LogixVVV0PLC的I/O模块,控制器,把罗克韦尔自动化公司推出EFPT过程控制实验装置作为控制对象,该系统带来了在I.个小型锅炉系统的精确控制锅炉的水位,把传感器和执行器的锅炉水位用于工业生产.
II系统概述
锅炉水位控制系统由EFPT过程控制设备,变频器,LogixVVV0PLC和I.台电脑组成.EFPT过程控制设备主要是模拟加热和I.个微型小锅炉的供水和排水系统.在工业生产中使用的传感器和驱动器在I.个小型锅炉系统,实现过程控制.该系统的执行机构不仅包括仪表,还有AC逆变器,加热控制器,加热器等.该系统通过I.个小型锅炉供热,供水和排水系统,是可靠和视觉模拟的工业现场.????
选定锅炉水位为控制变量.被控对象组成的水槽,磁力泵,锅炉和管道阀门.微硕士VISEIXIII.IV-ODAIV0变频器作为 *好棒文|www.hbsrm.com +Q: ^351916072*
执行机构采取LogixVVV0控制锅炉水位.组态软件RSViewIIIII和触摸屏PanelViewI.000相结合,实现实时监控.在设计上,设计简单的单回路锅炉液位值调整被选定为研究对象.该系统的组成如图I..????
图I.锅炉水位设定值调节系统
?变频器作为执行机构的设计,直接接收PLC的类比I/O端口输出,并转换成使变频器频率带动扬程水泵III相电机,改变进气口,锅炉水位调整到在最后的动态平衡.和配置软件用于监控画面设计,以实现计算机和触摸屏的锅炉水位长途和现场监测.
III建立被控对象的数学模型
建立控制系统数学模型的主要任务之I.是确定被控对象的数学模型.I.般来说,建立过程控制的数学模型的基本方法有两种:机理分析与实验方法.然而,为控制对象,其结构和内部流程是非常复杂的,它是很难确定的对象,只是通过自身内部的物理过程,并解决了系统的微分方程.此外,考虑非线性因素,分析机制,用I.些数学推导的近似和假设.虽然这些近似和假设有实践基础,但不能完全反映实际情况,甚至造成不可估量的影响.???
?因此,在本设计中,选择实验方法建立被控对象的数学模型.这种造型的基础上,在实际生产过程中,也就是说,建立数学模型为控制对象,通过过程识别和参数估计的输入和输出.在这个设计中,阶跃响应曲线法用于识别过程的数学模型.II0Hz的阶跃扰动输入信号施加到被控对象,并且,随着时间的变化可以映射输出的响应曲线.经过分析,控制对象的传递函数可以被定义.在实验的过程中,对象进行了多次测试.使用RSLogixV000趋势的监测功能曲线,I.0多个被控对象的阶跃响应曲线已被记录.平均,稳定时间,所有的参数:
TS≈VIIIIII..VIIVs,稳定值:H(∞)=VVIII.V,高峰时间:TP=IIIIXIV.IVs超调量:σ≈IIIX％.根据理论分析,控制对象是最有可能的II阶对象.
然而,区别是非常明显的理想II阶被控对象的阶跃响应曲线和实际曲线之间.所以理想的曲线不能反应其实际的特点.据推断,控制的对象可能是第II阶控制对象,其中包括零.的尝试和错误的方法和MATLAB仿真工具,用于获取曲线的参数接近被控对象的响应曲线的平均动态参数.如图II所示?????
图IIMATLAB绘制的控制对象的曲线
从图片可以看出,控制系统的近似传递函数
(I.)
可根据以下规则做I.些调整:??
I.)当零接近虚轴,稳定时间将更长,冲会更大,高峰时间会更小.与零闭幕虚轴,效果更明显.??
II)闭环主导根尖动态性能的影响是增加的高峰时间,减少超调量和调整时间.非参数模型来描述受控对象.换句话说,其中约描述受控对象的阶跃响应曲线是由于控制对象的复杂性和不确定性.
IV安装控制器参数
IV.I.控制算法的选择
近似??被控对象的数学模型建立后,形成I.个完整的反馈控制系统,可以提高开环控制系统的性能.PID调节器,即比例积分微分控制器是I.个控制环,广泛地应用于工业控制系统里的反馈机制.PID控制器通过调节给定值与测量值之间的偏差,给出正确的调整,从而有规律地纠正控制过程.PID控制器算法涉及到III个部分:比例,积分,微分.比例控制是对当前偏差的反应,积分控制是新近错误总数的反应,而微分控制则是错误变化率的反应.这III种控制的结合可用来调节过程系统,例如调节阀的位置, *好棒文|www.hbsrm.com +Q: ^351916072*
或者加热系统的电源调节.根据具体的工艺要求,通过PID控制器的参数整定,从而提供调节作用.控制器的响应可以被认为是对系统偏差的响应.注意I.点的是,PID算法不I.定就是系统或系统稳定性的最佳控制.I.些应用可能只需要运用I.到两种方法来提供适当的系统控制.这是通过把不想要的控制输出置零取得.在控制系统中存在P,PI,PD,PID调节器.PI调节器很普遍,因为微分控制对测量噪音非常敏感.积分作用的缺乏可以防止系统根据控制目标而达到它的目标值.PID是I.个理想的控制律,积分引入的比例,这可以消除残差,加上衍生的行动,这也提高了系统的稳定性的基础.根据控制对象的特点和实验室条件下,建立I.个单I.的闭环反馈控制回路为控制对象,PID算法用于实现锅炉水位控制.水平控制示意图如图III????
在I.定程度上打开出口阀,使液压放电不变.水位在给定体积的反馈比较的过程变量,可以得到的偏差.PID指令PID运算上的偏差,其结果是控制变量,因此可以改变变频器的频率来控制泵的转速.如果液面偏高,结果使控制变量较小,流入率降低,使液面降低,如果是偏低的水平上,结果使控制变量较大,增加的流入率,高液位.
IV.IIPID参数整定????
由于控制对象的传递函数包括I.个零的II阶环节,计算工作负荷相当大,无论在理论方法使用时调整PID参数根轨迹法,频率??特性法.和过程的数学模型只能反映动态参数的约,所以这是由理论计算得到的参数值的可靠性并不X分准确,将在现场不断调整.因此,工程参数优化选择,以寻求在设计PID参数.工程优化的常用方法是动态特性参数,稳定的边界法,衰减曲线法和外地经验,设置方法等,在PID参数的过程中,IV:I.衰减曲线法通过.步骤如下:???
?I.)在封闭系统中,调节器的积分时间设定最大(TI≈∞)和微分时间TD设置为零(TD=0).比例的巨大价值,多次执行给定值扰动实验,这I.比例将逐渐减少,直到记录曲线呈现到IV:I.削弱.然后,这I.比例称为IV:I.削弱比例σS两个相邻波峰之间的距离被称为阻尼周期Ts.在实验中,水平的定量检测为II00mm,然后得到系统的响应曲线和重组IV:I.衰减曲线(粗红线图IV????
测量:δS≈VIII,TS≈II.II;
??II)根据下面的公式,每个参数的监管?
?δ=0.VIII,δS≈VI.IV;?
?TI=0.III,TS≈VI.VI;??T
D=0.I.,TS≈II.II;?
?III)根据这些结果,调节参数设置.然后观察系统的动态过程和参数作出调整,以确定最佳工艺参数.
V监测设计??????
罗克韦尔自动化公司的RSViewIIIII软件和PanelBuilderIIIII软件分别用于显示器屏幕设计完成动画显示,参数设置,报表输出,电流曲线显示,历史曲线显示等功能.电脑和触摸屏实现远程和现场的锅炉液位控制.系统监视器的图像画面如图V所示??
图V监控系统主画面
?实现配置的主要工作是建立水位控制对象,使动画显示的场景.控制对象包括,inletting水流量,出口的水流量和锅炉水位的数值对象.当动画建立连接后,被称为基本图形元素和动画元件库在用户窗口,以构建配置图.由国家定义的图形对象和数据对象设置相应的属性和动画连接状态的定义.在完成设计开发系统,您可以切换到运行模式进行实时监测,控制系统和测试配置.
VI结论
?本文介绍了数学模型的建立控制对象的PID参数整定的PLC控制,ControlLogixVVV0EFPT过程控制系统的组成和运行.组态软件的使用扩展的通信功能.通过实验测试,控制曲线的超调小,过渡时间短,所以控制效果是比较理想的.这是可靠和直观的设备是适用于科研和教学,并在实际工业生产中具有重要的应用价值.
附件II:外文原文
BoilerlevelcontrolsystembasedonControlLogixVVV0PLC
Abstract-ThispaperisaresearchdesignbasedonEFPTprocesscontroldevice.Inthedesign,actualindustryfieldhasbeensimulatedandcorrespondingmodelinghasbeencarriedonfortheboilerlevelsystem.ThentheappropriatePIDparameterhasbeensortedoutandControlLogiaVVV0PLChasbeenusedtocontroltheentireboilerlevelsystem.
Atlast,acorrespondingcontrolinterfacehasbeenestablishedandtheboilerlevelhasbeenunderasafeandaccuratecontrol
Keywords:EFPT,PID,Modeling,Boilerlevel;
I.Introduction
Thetaskoftheindustrialboilerlevelcontrolistomaintainadynamicbalancebycontrollingthewaterflowandevaporation,sothatthedrumlevelcanbemaintainedinthetechnologicallevel,whichisanecessityforensuringsafeoperationandalsooneofthemainindicatorsoftheboilersnormaloperation.Waterlevelwhichistoohighwillaffecttheeffectofthesteam-waterseparation,buttoolowitiswillbreakringcycleorevencauseboilerexplosion.Toensureasafeandefficientproduction,theboilerlevelmustbestrictlycontrolledinmaintainingconstantorchangingonlyaccordingtoacertainrule.
UsingLogixVVV0PLCwithanalogyI/Omodules,launchedbyRockwellAutomationCompanyascontrollers,andEFPTprocesscontrolexperimentaldeviceascontrolobject,thissystemhavebroughttheboilerwaterlevelunderanaccuratecontrolinaminiboilersystemwithsensorsandactuatorsthatusedinindustrialproduction.
Fig.I.Boilerlevelsettingvalueadjustmentsystem
IISystemOverview
ThissystemiscomposedofanEFPTprocesscontroldevice,aninverter,aLogixVVV0PLCandacomputer.EFPTprocesscontroldeviceisasimulatedheatingandwatersupplyanddrainagesystemforamicro-smallboiler.Itrealizesprocesscontrolinaminiboilersystemwithsensorsandactuatorsusedinindustrialproduction.Theactuatorincludesnotonlymeasuringappliance,butalsoACinverter,heatingcontroller,heaterandsoon.Thesystemsimulatesindustryscenethroughamini-boilerheating,watersupplyanddrainagesystem,whichisreliableandvisual.
Inthedesign,boilerLevelwasselectedasthecontrolledvariable.Thecontrolledobjectiscomposedofthewatertrough,theforcepump,theboilerandthepipe-linevalve.MicroMasterVISEIXIII.IV-ODAIV0inverteristakenastheactuatorandtheboilerleveliscontrolledbyLogixVVV0.ConfigurationsoftwareRSViewIIIIIandtouchscreenPanelViewI.000arecombinedtorealizethereal-timemonitoring.Inthedesign,asimpledesignofsingle-loopboilerliquidlevelvalueadjustmentisselectedforthestudy.ThecompositionofthesystemisshowninFig.I..
Inthedesign,theinverterasanactuatordirectlyreceivesPLCanalogyI/Oportoutput,andconvertersintofrequencyofinvertersoastodrivetheIII-phasemotorintheliftpump,changetheinlet,andadjusttheboilerleveltothedynamicbalanceatlast.Andtheconfigurationsoftwareisusedtodesignmonitoringpicturetorealizethecomputerandthetouchscreentotheboilerlevellong-distanceandthescenemonitoring.
IIIEstablishingMathematicsmodelforthechargedobject
Oneofthemaintasksofestablishingcontrolsystemmathematicalmodelistodeterminethemathematicalmodelofthecontrolledobject.Generally,therearetwokindsofbasicmethodsforestablishingprocesscontrolmathematicalmodel:mechanismanalysisandexperimentalmethod.However,forcontrolledobjectwhosestructureandinternalprocessisverycomplex,itisverydifficulttodeterminetheobjectjustbyitsowninternalphysicalprocessandtosolveoutthedifferentialequationssystematically.Besides,consideringthenonlinearfactor,mechanismanalysisusedsomeapproximationandhypothesisformathematicaldeduction.Althoughtheseapproximationandassumptionshavepracticalbasis,butnotfullyreflectactualsituation,andevencauseincalculableeffects.
Therefore,inthisdesign,theexperimentalmethodischosentoestablishamathematicalmodelforcontrolledobject.Thiskindofmodelingisbasedontheinputandoutputintheactualproductionprocess,thatistosay,establishingmathematicalmodelforthecontrolledobjectthroughprocessidentificationandparameterestimation.Inthisdesign,stepresponsecurvemethodisusedtoidentifymathematicalmodelsoftheprocess.AII0Hzstepdisturbanceinputsignalisappliedtothechargedobject,andtheresponsecurveoftheoutputthatchangeswithtimecanbemapped.Aftertheanalysis,thetransferfunctionofthecontrolledobjectcanbedefined.Intheprocessofexperiment,theobjectwasconductedseveraltests.UsingRSLogixV000trendmonitoringfunctioncurve,morethanI.0chargedobjectstepresponsecurvehavebeenrecorded.Toalltheparametersforaverage,steadytime:ts≈VIIIIII..VIIVs,steadyvalue:h(∞)=VVIII.V,peaktime:tp=IIIIXIV.IVsovershoot:a%}IIIX%.Accordingtothetheoreticalanalysis,thecontrolledobjectisthemostlikelysecond-orderobject.
However,thedifferenceisveryapparentbetweentheidealsecond-ordercontrolledobjectstepresponsecurveandtheactualcurves.Sotheidealcurvecantresponsetoitsactualcharacteristics.Itisinferredthatthecontrolledobjectmaybethesecond-ordercontrolledobjectthatincludeszero.ThetryanderrormethodandMATLABsimulationtoolsareusedtogetacurvewhoseparametersareclosetotheaveragedynamicparametersofthecontrolledobjectsresponsecurve.ItisshowninFig.II.
Someadjustmentscanbemadeaccordingtothefollowingrules:
I.)Whenthezeroisclosertotheimaginaryaxis,settlingtimewillbelongerandtheovershootwillbebiggerandpeaktimewillbesmaller.Withthezeroclosingtotheimaginaryaxis,theeffectismoreobvious.
II)Theeffectwhichtheclosedloopdominantapiceshaveondynamicperformanceisincreasingthepeaktime,reducingtheovershootandadjustingtime.Nonparametricmodelisusedtodescribethecontrolledobject.Inotherwords,stepresponsecurvewhichapproximatelydescribethecontrolledobjectisusedbecauseofthecontrolledobjectscomplexityanduncertainty.
IVTheinstallationofcontrollerparameter
IV.I.Theselectionofcontrolalgorithm
Afterestablishingtheapproximatemathematicalmodelofthecontrolledobject,acompletefeedbackcontrolsystemcanbeformedtoimprovetheperformanceoftheopen-loopcontrolsystem.PIDisanidealcontrollawinthatintegralisintroducedbasingontheproportion,whichcaneliminatetheresidualerror,plusthederivativeaction,whichcanalsoimprovethestabilityofthesystem.Accordingtothecharacteristicsofthecontrolledobjectandlaboratoryconditions,asingle-loopfeedbackcontrolloopforthecontrolledobjectisestablished,andPIDalgorithmisusedtorealizeboilerlevelcontrol.TheschematicdiagramoflevelcontrolisshowninFig.III.
Opentheoutletvalvetoacertaindegree,andmakethehydraulicdischargeinvariable.Comparingtheprocessvariablesofthewaterlevelinfeedbackwiththegivenvolume,thedeviationcanbeobtained.PIDinstructiondoesPIDoperationonthedeviation,andtheresultsisacontrolvariable,sothefrequencyoftheinvertercanbechangedtocontroltherotatespeedofthepump.Iftheliquidlevelisonthehighside,theresultsmakethecontrolvariablesmaller,and
reducetherateofinflow,makeliquidlevellower;ifthelevelisonthelowside,theresultsmakethecontrolvariablelarger,andincreasetherateofinflow,makeliquidlevelhigher.
IV.IITheParameterTuningofPID
Becausethetransferfunctionofthecontrolledobjectincludesazerosecond-orderlink,thecomputationworkloadisquitebigregardlessofusingtheroot-locusmethodorthefrequencycharacteristiclawamongtheorymethodswhentuningPIDparameter.Andtheprocessmathematicalmodelcanonlyreflectdynamicparameterapproximately,sothereliabilityoftheparametervaluewhichisobtainedbythetheoreticalcalculationisnotveryaccurateanditwillbeadjustedconstantlyinthescene.Therefore,engineeringparametertuningischosentoseekthePIDparameterinthedesign.Thecommonmethodofengineeringtuningaredynamiccharacteristicparameters,thestableboundarylaw,thedecaycurvelawandfieldexperiencesettingmethod,etc.IntheprocessofPIDparameters,theIV:I.decaycurvelawis
adopted.Thestepsare:
I.)Intheclosedsystem,regulatorsintegraltimeissetthelargest(Ti≈∞)anddifferentialtimeTdissetzero(Td=0).Theproportionistakenthegreatvaluetoperformthegivenvalueperturbationexperimentrepeatedly,andtheproportionisreducedgraduallyuntiltherecordcurvepresentsuptoIV:I.weaken.ThentheproportioniscalledIV:I.weakenproportionss
andthedistancesbetweentwoneighboringwaveridgesarecalledIV:I.dampedcycleTs.Intheexperiment,thelevelquantitativetestissetfortheII00mm,andthenthesystemresponsecurveisobtainedandreorganizedIV:I.decaycurve(thickredlineisshowninFig.IV
Thusmeasuring:δs≈VIII,Ts≈II.II;
II)Accordingtothefollowingformula,eachparameteroftheregulatorsis
δ=0.VIII,δs≈VI.IV;
Ti=0.III,Ts≈VI.VI;
Td=0.I.,Ts≈II.II
III)Accordingtotheseresults,regulatorparametersareset.Thenthedynamicprocessofsystemisobservedandtheparametersaremadeadjustmenttodeterminetheoptimumparameters.
VMonitoringDesign
RSViewIIIIIsoftwareandPanelBuilderIIIIIsoftwareofRockwellAutomationCompanyarerespectivelyusedtodesignmonitorscreentocompletesuchfunctionasanimatingdisplay,parametersetting,reportoutput,thecurrentcurvedisplayandhistorycurvedisplayandsoon.Andmakethecomputerandtouchscreenachievetheremoteandon-sitecontroltotheboilerliquidlevel.ThepicturescreenofsystemmonitorisshowninFig.V
Themainworkofrealizingconfigurationistoestablishlevelcontrolobjectsandmakeanimatingdisplayscenes.Controlledobjectsincludeinlettingwaterflow,exportingwaterflowandthenumericalobjectoftheboilerlevel.Whenanimationconnectionisestablished,thebasicgraphicelementsandanimationcomponentlibraryarecalledintheuserwindowtoconstructconfigurationdiagram.Graphicobjectsanddataobjectsdefinedbythestatearesetinthestateofthecorrespondingattributeandanimationconnectionisdefined.Havingfinishedthedesignof
thedevelopingsystem,youcanswitchtorunmodetocarryonthereal-timemonitoringtothecontrolsystemandtestconfiguration.
VIConclusions
ThispaperhasintroducedthecompositionandrunningofEFPTprocesscontrolsystembasedonControlLogixVVV0PLCcontrol,themathematicalmodelestablishingofcontrolledobjectandtheparametertuningofPID.Theuseofconfigurationsoftwareextendsthecommunicationfunction.Throughexperimentaltesting,thecontrolcurvesovershootissmallandthetransitiontimeisshort,sothecontroleffectisquiteideal.Thisdevicebeingreliableandintuitiveissuitableforscientificresearchandteaching,andhasimportantapplicationvalueintheactualindustrialproduction.
控制系统
摘要本文是EFPT过程控制设备的研究设计.实际工业领域的设计,已经模拟和相应的建模beencarried锅炉水位系统.然后适当的PID参数已整理出ControlLogixVVV0PLC已被用来控制整个锅炉水位系统.最后,相应的控制界面建立好了,锅炉水位也已在安全和精确控制下
关键字:EFPT,PID控制,建模,锅炉水平;
I.引言
工业锅炉水位控制的任务是维持I.个系统运行动态的平衡,通过系统控制水的流量和蒸发,使汽包水位保持在合理的技术水平,这是确保锅炉安全运行的必要条件和主要指标之I..锅炉水位太高或太低都不可以,锅炉水位太高会影响汽水分离的效果,但是锅炉水位太低了也会影响汽水分离的效果,会破坏循环周期,甚至导致锅炉爆炸.为了确保锅炉的安全和高效的生产,必须严格控制锅炉的水位,保持锅炉内水位恒定或锅炉内水位在I.定的范围内变化.
使用LogixVVV0PLC的I/O模块,控制器,把罗克韦尔自动化公司推出EFPT过程控制实验装置作为控制对象,该系统带来了在I.个小型锅炉系统的精确控制锅炉的水位,把传感器和执行器的锅炉水位用于工业生产.
II系统概述
锅炉水位控制系统由EFPT过程控制设备,变频器,LogixVVV0PLC和I.台电脑组成.EFPT过程控制设备主要是模拟加热和I.个微型小锅炉的供水和排水系统.在工业生产中使用的传感器和驱动器在I.个小型锅炉系统,实现过程控制.该系统的执行机构不仅包括仪表,还有AC逆变器,加热控制器,加热器等.该系统通过I.个小型锅炉供热,供水和排水系统,是可靠和视觉模拟的工业现场.????
选定锅炉水位为控制变量.被控对象组成的水槽,磁力泵,锅炉和管道阀门.微硕士VISEIXIII.IV-ODAIV0变频器作为 *好棒文|www.hbsrm.com +Q: ^351916072*
执行机构采取LogixVVV0控制锅炉水位.组态软件RSViewIIIII和触摸屏PanelViewI.000相结合,实现实时监控.在设计上,设计简单的单回路锅炉液位值调整被选定为研究对象.该系统的组成如图I..????
图I.锅炉水位设定值调节系统
?变频器作为执行机构的设计,直接接收PLC的类比I/O端口输出,并转换成使变频器频率带动扬程水泵III相电机,改变进气口,锅炉水位调整到在最后的动态平衡.和配置软件用于监控画面设计,以实现计算机和触摸屏的锅炉水位长途和现场监测.
III建立被控对象的数学模型
建立控制系统数学模型的主要任务之I.是确定被控对象的数学模型.I.般来说,建立过程控制的数学模型的基本方法有两种:机理分析与实验方法.然而,为控制对象,其结构和内部流程是非常复杂的,它是很难确定的对象,只是通过自身内部的物理过程,并解决了系统的微分方程.此外,考虑非线性因素,分析机制,用I.些数学推导的近似和假设.虽然这些近似和假设有实践基础,但不能完全反映实际情况,甚至造成不可估量的影响.???
?因此,在本设计中,选择实验方法建立被控对象的数学模型.这种造型的基础上,在实际生产过程中,也就是说,建立数学模型为控制对象,通过过程识别和参数估计的输入和输出.在这个设计中,阶跃响应曲线法用于识别过程的数学模型.II0Hz的阶跃扰动输入信号施加到被控对象,并且,随着时间的变化可以映射输出的响应曲线.经过分析,控制对象的传递函数可以被定义.在实验的过程中,对象进行了多次测试.使用RSLogixV000趋势的监测功能曲线,I.0多个被控对象的阶跃响应曲线已被记录.平均,稳定时间,所有的参数:
TS≈VIIIIII..VIIVs,稳定值:H(∞)=VVIII.V,高峰时间:TP=IIIIXIV.IVs超调量:σ≈IIIX％.根据理论分析,控制对象是最有可能的II阶对象.
然而,区别是非常明显的理想II阶被控对象的阶跃响应曲线和实际曲线之间.所以理想的曲线不能反应其实际的特点.据推断,控制的对象可能是第II阶控制对象,其中包括零.的尝试和错误的方法和MATLAB仿真工具,用于获取曲线的参数接近被控对象的响应曲线的平均动态参数.如图II所示?????
图IIMATLAB绘制的控制对象的曲线
从图片可以看出,控制系统的近似传递函数
(I.)
可根据以下规则做I.些调整:??
I.)当零接近虚轴,稳定时间将更长,冲会更大,高峰时间会更小.与零闭幕虚轴,效果更明显.??
II)闭环主导根尖动态性能的影响是增加的高峰时间,减少超调量和调整时间.非参数模型来描述受控对象.换句话说,其中约描述受控对象的阶跃响应曲线是由于控制对象的复杂性和不确定性.
IV安装控制器参数
IV.I.控制算法的选择
近似??被控对象的数学模型建立后,形成I.个完整的反馈控制系统,可以提高开环控制系统的性能.PID调节器,即比例积分微分控制器是I.个控制环,广泛地应用于工业控制系统里的反馈机制.PID控制器通过调节给定值与测量值之间的偏差,给出正确的调整,从而有规律地纠正控制过程.PID控制器算法涉及到III个部分:比例,积分,微分.比例控制是对当前偏差的反应,积分控制是新近错误总数的反应,而微分控制则是错误变化率的反应.这III种控制的结合可用来调节过程系统,例如调节阀的位置, *好棒文|www.hbsrm.com +Q: ^351916072*
或者加热系统的电源调节.根据具体的工艺要求,通过PID控制器的参数整定,从而提供调节作用.控制器的响应可以被认为是对系统偏差的响应.注意I.点的是,PID算法不I.定就是系统或系统稳定性的最佳控制.I.些应用可能只需要运用I.到两种方法来提供适当的系统控制.这是通过把不想要的控制输出置零取得.在控制系统中存在P,PI,PD,PID调节器.PI调节器很普遍,因为微分控制对测量噪音非常敏感.积分作用的缺乏可以防止系统根据控制目标而达到它的目标值.PID是I.个理想的控制律,积分引入的比例,这可以消除残差,加上衍生的行动,这也提高了系统的稳定性的基础.根据控制对象的特点和实验室条件下,建立I.个单I.的闭环反馈控制回路为控制对象,PID算法用于实现锅炉水位控制.水平控制示意图如图III????
在I.定程度上打开出口阀,使液压放电不变.水位在给定体积的反馈比较的过程变量,可以得到的偏差.PID指令PID运算上的偏差,其结果是控制变量,因此可以改变变频器的频率来控制泵的转速.如果液面偏高,结果使控制变量较小,流入率降低,使液面降低,如果是偏低的水平上,结果使控制变量较大,增加的流入率,高液位.
IV.IIPID参数整定????
由于控制对象的传递函数包括I.个零的II阶环节,计算工作负荷相当大,无论在理论方法使用时调整PID参数根轨迹法,频率??特性法.和过程的数学模型只能反映动态参数的约,所以这是由理论计算得到的参数值的可靠性并不X分准确,将在现场不断调整.因此,工程参数优化选择,以寻求在设计PID参数.工程优化的常用方法是动态特性参数,稳定的边界法,衰减曲线法和外地经验,设置方法等,在PID参数的过程中,IV:I.衰减曲线法通过.步骤如下:???
?I.)在封闭系统中,调节器的积分时间设定最大(TI≈∞)和微分时间TD设置为零(TD=0).比例的巨大价值,多次执行给定值扰动实验,这I.比例将逐渐减少,直到记录曲线呈现到IV:I.削弱.然后,这I.比例称为IV:I.削弱比例σS两个相邻波峰之间的距离被称为阻尼周期Ts.在实验中,水平的定量检测为II00mm,然后得到系统的响应曲线和重组IV:I.衰减曲线(粗红线图IV????
测量:δS≈VIII,TS≈II.II;
??II)根据下面的公式,每个参数的监管?
?δ=0.VIII,δS≈VI.IV;?
?TI=0.III,TS≈VI.VI;??T
D=0.I.,TS≈II.II;?
?III)根据这些结果,调节参数设置.然后观察系统的动态过程和参数作出调整,以确定最佳工艺参数.
V监测设计??????
罗克韦尔自动化公司的RSViewIIIII软件和PanelBuilderIIIII软件分别用于显示器屏幕设计完成动画显示,参数设置,报表输出,电流曲线显示,历史曲线显示等功能.电脑和触摸屏实现远程和现场的锅炉液位控制.系统监视器的图像画面如图V所示??
图V监控系统主画面
?实现配置的主要工作是建立水位控制对象,使动画显示的场景.控制对象包括,inletting水流量,出口的水流量和锅炉水位的数值对象.当动画建立连接后,被称为基本图形元素和动画元件库在用户窗口,以构建配置图.由国家定义的图形对象和数据对象设置相应的属性和动画连接状态的定义.在完成设计开发系统,您可以切换到运行模式进行实时监测,控制系统和测试配置.
VI结论
?本文介绍了数学模型的建立控制对象的PID参数整定的PLC控制,ControlLogixVVV0EFPT过程控制系统的组成和运行.组态软件的使用扩展的通信功能.通过实验测试,控制曲线的超调小,过渡时间短,所以控制效果是比较理想的.这是可靠和直观的设备是适用于科研和教学,并在实际工业生产中具有重要的应用价值.
附件II:外文原文
BoilerlevelcontrolsystembasedonControlLogixVVV0PLC
Abstract-ThispaperisaresearchdesignbasedonEFPTprocesscontroldevice.Inthedesign,actualindustryfieldhasbeensimulatedandcorrespondingmodelinghasbeencarriedonfortheboilerlevelsystem.ThentheappropriatePIDparameterhasbeensortedoutandControlLogiaVVV0PLChasbeenusedtocontroltheentireboilerlevelsystem.
Atlast,acorrespondingcontrolinterfacehasbeenestablishedandtheboilerlevelhasbeenunderasafeandaccuratecontrol
Keywords:EFPT,PID,Modeling,Boilerlevel;
I.Introduction
Thetaskoftheindustrialboilerlevelcontrolistomaintainadynamicbalancebycontrollingthewaterflowandevaporation,sothatthedrumlevelcanbemaintainedinthetechnologicallevel,whichisanecessityforensuringsafeoperationandalsooneofthemainindicatorsoftheboilersnormaloperation.Waterlevelwhichistoohighwillaffecttheeffectofthesteam-waterseparation,buttoolowitiswillbreakringcycleorevencauseboilerexplosion.Toensureasafeandefficientproduction,theboilerlevelmustbestrictlycontrolledinmaintainingconstantorchangingonlyaccordingtoacertainrule.
UsingLogixVVV0PLCwithanalogyI/Omodules,launchedbyRockwellAutomationCompanyascontrollers,andEFPTprocesscontrolexperimentaldeviceascontrolobject,thissystemhavebroughttheboilerwaterlevelunderanaccuratecontrolinaminiboilersystemwithsensorsandactuatorsthatusedinindustrialproduction.
Fig.I.Boilerlevelsettingvalueadjustmentsystem
IISystemOverview
ThissystemiscomposedofanEFPTprocesscontroldevice,aninverter,aLogixVVV0PLCandacomputer.EFPTprocesscontroldeviceisasimulatedheatingandwatersupplyanddrainagesystemforamicro-smallboiler.Itrealizesprocesscontrolinaminiboilersystemwithsensorsandactuatorsusedinindustrialproduction.Theactuatorincludesnotonlymeasuringappliance,butalsoACinverter,heatingcontroller,heaterandsoon.Thesystemsimulatesindustryscenethroughamini-boilerheating,watersupplyanddrainagesystem,whichisreliableandvisual.
Inthedesign,boilerLevelwasselectedasthecontrolledvariable.Thecontrolledobjectiscomposedofthewatertrough,theforcepump,theboilerandthepipe-linevalve.MicroMasterVISEIXIII.IV-ODAIV0inverteristakenastheactuatorandtheboilerleveliscontrolledbyLogixVVV0.ConfigurationsoftwareRSViewIIIIIandtouchscreenPanelViewI.000arecombinedtorealizethereal-timemonitoring.Inthedesign,asimpledesignofsingle-loopboilerliquidlevelvalueadjustmentisselectedforthestudy.ThecompositionofthesystemisshowninFig.I..
Inthedesign,theinverterasanactuatordirectlyreceivesPLCanalogyI/Oportoutput,andconvertersintofrequencyofinvertersoastodrivetheIII-phasemotorintheliftpump,changetheinlet,andadjusttheboilerleveltothedynamicbalanceatlast.Andtheconfigurationsoftwareisusedtodesignmonitoringpicturetorealizethecomputerandthetouchscreentotheboilerlevellong-distanceandthescenemonitoring.
IIIEstablishingMathematicsmodelforthechargedobject
Oneofthemaintasksofestablishingcontrolsystemmathematicalmodelistodeterminethemathematicalmodelofthecontrolledobject.Generally,therearetwokindsofbasicmethodsforestablishingprocesscontrolmathematicalmodel:mechanismanalysisandexperimentalmethod.However,forcontrolledobjectwhosestructureandinternalprocessisverycomplex,itisverydifficulttodeterminetheobjectjustbyitsowninternalphysicalprocessandtosolveoutthedifferentialequationssystematically.Besides,consideringthenonlinearfactor,mechanismanalysisusedsomeapproximationandhypothesisformathematicaldeduction.Althoughtheseapproximationandassumptionshavepracticalbasis,butnotfullyreflectactualsituation,andevencauseincalculableeffects.
Therefore,inthisdesign,theexperimentalmethodischosentoestablishamathematicalmodelforcontrolledobject.Thiskindofmodelingisbasedontheinputandoutputintheactualproductionprocess,thatistosay,establishingmathematicalmodelforthecontrolledobjectthroughprocessidentificationandparameterestimation.Inthisdesign,stepresponsecurvemethodisusedtoidentifymathematicalmodelsoftheprocess.AII0Hzstepdisturbanceinputsignalisappliedtothechargedobject,andtheresponsecurveoftheoutputthatchangeswithtimecanbemapped.Aftertheanalysis,thetransferfunctionofthecontrolledobjectcanbedefined.Intheprocessofexperiment,theobjectwasconductedseveraltests.UsingRSLogixV000trendmonitoringfunctioncurve,morethanI.0chargedobjectstepresponsecurvehavebeenrecorded.Toalltheparametersforaverage,steadytime:ts≈VIIIIII..VIIVs,steadyvalue:h(∞)=VVIII.V,peaktime:tp=IIIIXIV.IVsovershoot:a%}IIIX%.Accordingtothetheoreticalanalysis,thecontrolledobjectisthemostlikelysecond-orderobject.
However,thedifferenceisveryapparentbetweentheidealsecond-ordercontrolledobjectstepresponsecurveandtheactualcurves.Sotheidealcurvecantresponsetoitsactualcharacteristics.Itisinferredthatthecontrolledobjectmaybethesecond-ordercontrolledobjectthatincludeszero.ThetryanderrormethodandMATLABsimulationtoolsareusedtogetacurvewhoseparametersareclosetotheaveragedynamicparametersofthecontrolledobjectsresponsecurve.ItisshowninFig.II.
Someadjustmentscanbemadeaccordingtothefollowingrules:
I.)Whenthezeroisclosertotheimaginaryaxis,settlingtimewillbelongerandtheovershootwillbebiggerandpeaktimewillbesmaller.Withthezeroclosingtotheimaginaryaxis,theeffectismoreobvious.
II)Theeffectwhichtheclosedloopdominantapiceshaveondynamicperformanceisincreasingthepeaktime,reducingtheovershootandadjustingtime.Nonparametricmodelisusedtodescribethecontrolledobject.Inotherwords,stepresponsecurvewhichapproximatelydescribethecontrolledobjectisusedbecauseofthecontrolledobjectscomplexityanduncertainty.
IVTheinstallationofcontrollerparameter
IV.I.Theselectionofcontrolalgorithm
Afterestablishingtheapproximatemathematicalmodelofthecontrolledobject,acompletefeedbackcontrolsystemcanbeformedtoimprovetheperformanceoftheopen-loopcontrolsystem.PIDisanidealcontrollawinthatintegralisintroducedbasingontheproportion,whichcaneliminatetheresidualerror,plusthederivativeaction,whichcanalsoimprovethestabilityofthesystem.Accordingtothecharacteristicsofthecontrolledobjectandlaboratoryconditions,asingle-loopfeedbackcontrolloopforthecontrolledobjectisestablished,andPIDalgorithmisusedtorealizeboilerlevelcontrol.TheschematicdiagramoflevelcontrolisshowninFig.III.
Opentheoutletvalvetoacertaindegree,andmakethehydraulicdischargeinvariable.Comparingtheprocessvariablesofthewaterlevelinfeedbackwiththegivenvolume,thedeviationcanbeobtained.PIDinstructiondoesPIDoperationonthedeviation,andtheresultsisacontrolvariable,sothefrequencyoftheinvertercanbechangedtocontroltherotatespeedofthepump.Iftheliquidlevelisonthehighside,theresultsmakethecontrolvariablesmaller,and
reducetherateofinflow,makeliquidlevellower;ifthelevelisonthelowside,theresultsmakethecontrolvariablelarger,andincreasetherateofinflow,makeliquidlevelhigher.
IV.IITheParameterTuningofPID
Becausethetransferfunctionofthecontrolledobjectincludesazerosecond-orderlink,thecomputationworkloadisquitebigregardlessofusingtheroot-locusmethodorthefrequencycharacteristiclawamongtheorymethodswhentuningPIDparameter.Andtheprocessmathematicalmodelcanonlyreflectdynamicparameterapproximately,sothereliabilityoftheparametervaluewhichisobtainedbythetheoreticalcalculationisnotveryaccurateanditwillbeadjustedconstantlyinthescene.Therefore,engineeringparametertuningischosentoseekthePIDparameterinthedesign.Thecommonmethodofengineeringtuningaredynamiccharacteristicparameters,thestableboundarylaw,thedecaycurvelawandfieldexperiencesettingmethod,etc.IntheprocessofPIDparameters,theIV:I.decaycurvelawis
adopted.Thestepsare:
I.)Intheclosedsystem,regulatorsintegraltimeissetthelargest(Ti≈∞)anddifferentialtimeTdissetzero(Td=0).Theproportionistakenthegreatvaluetoperformthegivenvalueperturbationexperimentrepeatedly,andtheproportionisreducedgraduallyuntiltherecordcurvepresentsuptoIV:I.weaken.ThentheproportioniscalledIV:I.weakenproportionss
andthedistancesbetweentwoneighboringwaveridgesarecalledIV:I.dampedcycleTs.Intheexperiment,thelevelquantitativetestissetfortheII00mm,andthenthesystemresponsecurveisobtainedandreorganizedIV:I.decaycurve(thickredlineisshowninFig.IV
Thusmeasuring:δs≈VIII,Ts≈II.II;
II)Accordingtothefollowingformula,eachparameteroftheregulatorsis
δ=0.VIII,δs≈VI.IV;
Ti=0.III,Ts≈VI.VI;
Td=0.I.,Ts≈II.II
III)Accordingtotheseresults,regulatorparametersareset.Thenthedynamicprocessofsystemisobservedandtheparametersaremadeadjustmenttodeterminetheoptimumparameters.
VMonitoringDesign
RSViewIIIIIsoftwareandPanelBuilderIIIIIsoftwareofRockwellAutomationCompanyarerespectivelyusedtodesignmonitorscreentocompletesuchfunctionasanimatingdisplay,parametersetting,reportoutput,thecurrentcurvedisplayandhistorycurvedisplayandsoon.Andmakethecomputerandtouchscreenachievetheremoteandon-sitecontroltotheboilerliquidlevel.ThepicturescreenofsystemmonitorisshowninFig.V
Themainworkofrealizingconfigurationistoestablishlevelcontrolobjectsandmakeanimatingdisplayscenes.Controlledobjectsincludeinlettingwaterflow,exportingwaterflowandthenumericalobjectoftheboilerlevel.Whenanimationconnectionisestablished,thebasicgraphicelementsandanimationcomponentlibraryarecalledintheuserwindowtoconstructconfigurationdiagram.Graphicobjectsanddataobjectsdefinedbythestatearesetinthestateofthecorrespondingattributeandanimationconnectionisdefined.Havingfinishedthedesignof
thedevelopingsystem,youcanswitchtorunmodetocarryonthereal-timemonitoringtothecontrolsystemandtestconfiguration.
VIConclusions
ThispaperhasintroducedthecompositionandrunningofEFPTprocesscontrolsystembasedonControlLogixVVV0PLCcontrol,themathematicalmodelestablishingofcontrolledobjectandtheparametertuningofPID.Theuseofconfigurationsoftwareextendsthecommunicationfunction.Throughexperimentaltesting,thecontrolcurvesovershootissmallandthetransitiontimeisshort,sothecontroleffectisquiteideal.Thisdevicebeingreliableandintuitiveissuitableforscientificresearchandteaching,andhasimportantapplicationvalueintheactualindustrialproduction.
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