《水處理技術(shù)（雙語）》課件-過程控制基礎(chǔ)知識

Processcontrolbasics過程控制基礎(chǔ)知識01

過程控制是生產(chǎn)過程的自動化控制的簡稱，是自動化技術(shù)的重要組成部分。Processcontrolistheabbreviationfortheautomaticcontrolofproductionprocessesandisanimportantpartofautomationtechnology.02是對生產(chǎn)過程中的溫度、壓力、流量、液（物）位、成分和物性（物體性能）等工藝參數(shù)進行控制，Itisthecontrolofprocessparameterssuchastemperature,pressure,flow,liquid(material)level,compositionandphysicalproperties(objectproperties)intheproductionprocess.使其保持為定值或按照一定規(guī)律變化，以確保產(chǎn)品質(zhì)量和生產(chǎn)安全，并使生產(chǎn)過程按照最優(yōu)目標自動進行。sothattheyarekeptataconstantvalueorchangeaccordingtoacertainruletoensureproductqualityandproductionsafetyandtomaketheproductionprocessautomaticaccordingtotheoptimaltarget.過程控制的概念Theconceptofprocesscontrol1.由被控過程和自動化儀表組成Composedofcontrolledprocessesandautomationinstruments2.被控過程復(fù)雜多樣，通用控制系統(tǒng)難以設(shè)計Thecontrolledprocessiscomplexanddiverse,anditisdifficulttodesignageneralcontrolsystem3.控制方案豐富多彩，控制要求越來越高Thecontrolschemeiscolorfulandthecontrolrequirementsaregettinghigherandhigher4.控制過程大多屬于慢變過程與參量控制Mostofthecontrolprocessesareslow-varyingprocessesandparametriccontrol5.定值控制是過程控制的主要形式Constantvaluecontrolisthemainformofprocesscontrol圖為過程控制流程圖Thediagramshowstheprocesscontrolflowchart過程控制的特點Characteristicsofprocesscontrol隨著中國社會經(jīng)濟的飛速發(fā)展,科學(xué)技術(shù)的不斷進步,過程控制也逐漸擴大了應(yīng)用范圍,并且重要性逐年凸顯。WithChina'srapidsocio-economicdevelopmentandthecontinuousadvancementofscienceandtechnology,processcontrolisgraduallyexpandingitsscopeofapplicationandbecomingmoreandmoreimportanteveryyear.常常體現(xiàn)在石油、化工、電力、冶金、水處理、食品、飲料、制藥、建材、核能等方面。Itisoftenfoundinpetroleum,chemical,electricpower,metallurgy,watertreatment,food,beverage,pharmaceutical,buildingmaterials,nuclearenergyandotherareas.過程控制運用領(lǐng)域Processcontrolapplicationareas過程控制的要求Requirementsforprocesscontrol它包括安全性、穩(wěn)定性、經(jīng)濟性。Itincludessafety,stabilityandeconomy.安全性：是指在整個生產(chǎn)過程中，要確認人身和設(shè)備的安全，這是最重要的，也是最基本的要求。常采用越限報警、聯(lián)鎖保護、在線故障診斷、容錯控制系統(tǒng)等方法來保證生產(chǎn)運行的安全性。Safety:Itmeansthatthesafetyofpeopleandequipmentshouldbeconfirmedduringthewholeproductionprocess,whichisthemostimportantandbasicrequirement.Out-of-limitalarms,interlockingprotection,onlinefaultdiagnosisandfault-tolerantcontrolsystemsareoftenusedtoensurethesafetyofproductionoperation.過程控制的要求Requirementsforprocesscontrol穩(wěn)定性：是指系統(tǒng)具有抑制外部干擾、保持生產(chǎn)過程長期穩(wěn)定運行的能力，這也是過程控制能夠正常運行的基本保證。Stability:referstotheabilityofthesystemtosuppressexternaldisturbancesandmaintainthelong-termstableoperationoftheproductionprocess,whichisthebasicguaranteethattheprocesscontrolcanoperatenormally.過程控制的要求Requirementsforprocesscontrol經(jīng)濟性：是指要求生產(chǎn)成本低而且效率高，這是也現(xiàn)代工業(yè)生產(chǎn)所追求的目標。Economical:therequirementforlowproductioncostsandhighefficiency,whichisalsothegoalofmodernindustrialproduction.過程控制的組成Componentsofprocesscontrol01控制器：接收傳感器的信號與給定值比較，作出控制決策送指令給執(zhí)行器Controller:Receivesthesignalfromthesensorandcomparesitwiththegivenvalue,makescontroldecisionsandsendsinstructionstotheactuator02執(zhí)行器：執(zhí)行控制器指令，改變操縱變量，對生產(chǎn)過程實施控制作用

Actuator:executesthecontroller'sinstructions,changesthemanipulatedvariablesandimplementsthecontrolrolefortheproductionprocess03傳感器：也叫變送器，對被控變量進行檢測并轉(zhuǎn)換成標準信號送控制器

sensors:alsocalledtransmitters,thecontrolledvariablesaredetectedandconvertedintostandardsignalssenttothecontroller04被控對象：被控制的生產(chǎn)過程或設(shè)備Controlledobject:theproductionprocessorequipmenttobecontrolled1）被控量y(t)：也叫被控參數(shù)，被控過程內(nèi)要求保持穩(wěn)定的工藝參數(shù)。Thecontrolledquantityy(t):alsocalledthecontrolledparameter,theprocessparameterthatisrequiredtobekeptstablewithinthecontrolledprocess.2）控制變量q(t)：也叫控制參數(shù)或控制輸出（CO），使被控參數(shù)保持期望值的物料量或能量值，工程上有時也稱為控制介質(zhì)。

Controlvariableq(t):alsocalledcontrolparameterorcontroloutput(CO),theamountofmaterialorenergyvaluerequiredtomaintainthedesiredvalueofthecontrolledparameter,sometimesreferredtoasthecontrolmediuminengineering.3）干擾量f(t)：也稱干擾因素或擾動，除被控參數(shù)外，作用于被控過程并引起被控參數(shù)變化的各種因素。

theamountofdisturbancef(t):alsoknownasdisturbancefactorsordisturbances,inadditiontothecontrolledparameters,theroleofthecontrolledprocessandcausechangesinthecontrolledparametersofvariousfactors.4）設(shè)定值r(t)：也叫輸入值，與被控參數(shù)相對應(yīng)的設(shè)定值。setvaluer(t):alsocalledinputvalue,thesetvaluecorrespondingtotheparameterbeingcontrolled.5）反饋值z(t)：被控參數(shù)經(jīng)測量變送后的實際測量值。Feedbackvaluez(t):Theactualmeasuredvalueofthecontrolledparameterafterthemeasuredtransmission6）偏差e(t)：設(shè)定值與反饋值之差。Deviatione(t):Thedifferencebetweenthesetvalueandthefeedbackvalue.7）控制變量u(t)：也稱控制作用，是控制器的輸出值（控制信號）。Controlvariableu(t):alsoknownasthecontroleffect,istheoutputvalueofthecontroller(controlsignal).過程控制的常用術(shù)語Commontermsusedinprocesscontrol01按被控參數(shù)分：溫度控制、壓力控制、流量控制、液位控制、成分控制……Accordingtothecontrolledparameters:temperaturecontrol,pressurecontrol,flowcontrol,liquidlevelcontrol,compositioncontrol......02按被控量的多少分：單值控制、多值控制Accordingtothenumberofcontrolledquantities:singlevaluecontrol,multi-valuecontrol03按控制結(jié)構(gòu)分：開環(huán)控制、閉環(huán)控制（例如PID)Bycontrolstructure:open-loopcontrol,closed-loopcontrol(e.g.PID)過程控制分類Processcontrolclassification1）定義：若系統(tǒng)的輸出信號對控制作用沒有影響，則稱為開環(huán)控制系統(tǒng)。Definition:Iftheoutputsignalofthesystemhasnoeffectonthecontrolaction,itiscalledanopen-loopcontrolsystem.開環(huán)控制Open-loopcontrol開環(huán)控制Open-loopcontrol2）優(yōu)點：結(jié)構(gòu)相對較簡單、維護容易、成本低。被控量的控制精度取決于系統(tǒng)各環(huán)節(jié)的精度Advantages:relativelysimplestructure,easymaintenanceandlowcost.Thecontrolaccuracyofthecontrolledquantitydependsontheaccuracyofeachlinkofthesystem3）缺點：對元器件要求較高、抗干擾能力差。無法自動補償系統(tǒng)干擾對被控量帶來的影響。Disadvantages:highrequirementsforcomponents,poorimmunitytointerference.Cannotautomaticallycompensatefortheeffectsofsystemdisturbancesonthecontrolledquantity.1）定義：系統(tǒng)的輸出信號對控制作用有直接影響的控制系統(tǒng)，就稱為閉環(huán)控制系統(tǒng)。在閉環(huán)控制系統(tǒng)中，系統(tǒng)的輸出信號通過反饋環(huán)節(jié)返回到輸入端，形成閉合環(huán)路，故又稱為反饋控制系統(tǒng)。

閉環(huán)控制ClosedloopcontrolDefinition:Acontrolsysteminwhichtheoutputsignalofthesystemhasadirecteffectonthecontrolactionisknownasaclosed-loopcontrolsystem.Inaclosed-loopcontrolsystem,theoutputsignalofthesystemisreturnedtotheinputthroughafeedbacklink,formingaclosedloop,soitisalsoknownasafeedbackcontrolsystem.閉環(huán)控制Closedloopcontrol2）優(yōu)點：抗干擾能力強?？刂凭仁墉h(huán)節(jié)的轉(zhuǎn)換精度較小。Advantages:Highresistancetointerference.Controlaccuracyislessaffectedbytheconversionaccuracyofthelink.3）缺點：Disadvantages：

控制作用對干擾作用有時間滯后。Controlactionhasatimelagagainstdisturbingeffects.

控制過程可能產(chǎn)生振蕩。Controlprocessmayproduceoscillations.

結(jié)構(gòu)復(fù)雜、維護不易、可能存在穩(wěn)定性問題。Complexstructure,noteasytomaintain,mayhavestabilityproblems.自動化儀表的相關(guān)知識Knowledgeofautomationinstrumentation1）定義：自動化儀表由若干自動化元件構(gòu)成的，具有較完善功能的自動化技術(shù)工具。Definition:Automationinstrumentationconsistsofanumberofautomationcomponents,withamorecompletefunctionofautomationtechnologytools.自動化儀表一般同時具有測量、顯示、記錄或測量、控制、報警等數(shù)種功能。Automationinstrumentsgenerallyhaveseveralfunctionsatthesametime,suchasmeasuring,displaying,recordingormeasuring,controlling,andalarming.過程控制的要求Requirementsforprocesscontrol2）分類ClassificationA.按儀表用途不同分為：檢測儀表、顯示儀表、轉(zhuǎn)換和傳輸儀表、調(diào)節(jié)控制儀表、執(zhí)行器。

Accordingtothedifferentusesofinstrumentsaredividedinto:detectioninstruments,displayinstruments,conversionandtransmissioninstruments,regulationandcontrolinstruments,actuators.B.按儀表的組成形式不同分為：基地式儀表、單元組合式儀表、組裝式電子綜合控制裝置、集中分散型控制系統(tǒng)。Accordingtothedifferentformsofinstrumentcomposition:basetypeinstrument,unitcombinationinstrument,assembledelectronicintegratedcontroldevice,centralizeddecentralizedcontrolsystem.過程控制的要求Require