TemperatureTransmitter溫度變送器落版在此謝聰XieCong主講教師Teacher溫度變送器TemperatureTransmitter溫度變送器Temperaturetransmitter標(biāo)準(zhǔn)信號(hào)Standardsignal讓數(shù)據(jù)在設(shè)備間順暢“溝通”Sothatdata"communicate"smoothlybetweendevices溫度信號(hào)Temperaturesignal溫度變送器TemperatureTransmitterCaseimport案例導(dǎo)入化工生產(chǎn)中常見(jiàn)的反應(yīng)釜溫度控制場(chǎng)景中，溫度傳感器實(shí)時(shí)監(jiān)測(cè)反應(yīng)釜內(nèi)的溫度，但它輸出的信號(hào)無(wú)法直接被控制系統(tǒng)識(shí)別和處理。Inacommonreactortemperaturecontrolscenarioinchemicalproduction,thetemperaturesensormonitorsthetemperatureinthereactorinrealtime,

butthesignalitoutputscannotbedirectlyidentifiedandprocessedbythecontrolsystem.Caseimport案例導(dǎo)入它將溫度傳感器輸出的非標(biāo)準(zhǔn)信號(hào)轉(zhuǎn)換為標(biāo)準(zhǔn)信號(hào)，如DC4～20mA或1～5V，使控制系統(tǒng)能夠準(zhǔn)確地接收和處理溫度數(shù)據(jù)，從而及時(shí)調(diào)整反應(yīng)條件，確保反應(yīng)在安全、高效的狀態(tài)下進(jìn)行。Itconvertsthenon-standardsignaloutputbythetemperaturesensorintoastandardsignal,suchasDC4~20mAor1~5V,sothatthecontrolsystemcanaccuratelyreceiveandprocessthetemperaturedata,therebyadjustingthereactionconditionsintimeandensuringsafeandefficientreaction.溫度變送器TemperatureTransmitterWorkingprincipleoftemperaturetransmitter溫度變送器的工作原理Workingprincipleoftemperaturetransmitter溫度變送器的工作原理是將熱電偶、熱電阻等溫度傳感器輸出的非標(biāo)準(zhǔn)檢測(cè)信號(hào)，轉(zhuǎn)換為符合控制系統(tǒng)要求的標(biāo)準(zhǔn)信號(hào)，以實(shí)現(xiàn)傳感器信號(hào)與控制系統(tǒng)的適配。Istoconvertthenon-standarddetectionsignaloutputbytemperaturesensorssuchasthermocouplesandthermalresistorsintostandardsignalsthatmeettherequirementsofthecontrolsystem,soastorealizetheadaptationofthesensorsignaltothecontrolsystem.溫度變送器的核心任務(wù)Thecoremissionofatemperaturetransmitter模擬控制系統(tǒng)的信號(hào)標(biāo)準(zhǔn)SignalstandardsforanalogcontrolsystemsⅡ型：DC0～10mA、0～10VTypeII:DC0-10mA,0-10VⅢ型：DC4～20mA、1～5VTypeIII:DC4~20mA,1~5V數(shù)字控制系統(tǒng)的信號(hào)標(biāo)準(zhǔn)SignalstandardsfordigitalcontrolsystemsFF協(xié)議、HART協(xié)議FFprotocol,HARTprotocolWorkingprincipleoftemperaturetransmitter溫度變送器的工作原理模擬式溫度變送器Analogtemperaturetransmitter結(jié)構(gòu)相對(duì)簡(jiǎn)單Relativelysimplestructure響應(yīng)速度快Fastresponse成本低廉LowcostWorkingprincipleoftemperaturetransmitter溫度變送器的工作原理DDZ-III型溫度變送器可與熱電偶、熱電阻配套使用，將傳感器信號(hào)轉(zhuǎn)換成標(biāo)準(zhǔn)4~20mA直流信號(hào)輸出。DDZ-IIItemperaturetransmittercanbeusedinconjunctionwiththermocouplesandthermalresistorstoconvertsensorsignalsintostandard4~20mADCsignaloutput.模擬式溫度變送器Analogtemperaturetransmitter傳感元件

Sensingelement

輸入電路

Inputcircuit

被測(cè)溫度

Measuredtemperature

電信號(hào)

Electricalsignal

＋反饋電路

Feedbackcircuit

－輸出電流4~20mA

Outputcurrent4~20mA

放大電路

Amplificationcircuit

DDZ-Ⅲ型溫度變送器組成原理圖SchematicDiagramofDDZ-ⅢTemperatureTransmitterCompositionWorkingprincipleoftemperaturetransmitter溫度變送器的工作原理如圖所示為熱電偶溫度變送器的輸入電路，Et為熱電偶的輸出電勢(shì)，其輸出回路中串接一個(gè)電橋電路，以實(shí)現(xiàn)熱電偶的冷端補(bǔ)償和零點(diǎn)遷移。Thefigureshowstheinputcircuitofthethermocoupletemperaturetransmitter.Etistheoutputpotentialofthethermocouple,withanelectricbridgecircuitconnectedinseriesintheoutputcircuitthereoftorealizethecoldendcompensationandzeroshiftofthethermocouple.輸入電路Inputcircuit

熱電偶溫度變送器輸入電路

InputcircuitofthermocoupletemperaturetransmitterRCu用銅絲繞制，與熱電偶冷端處同一溫度環(huán)境，起冷端溫度補(bǔ)償作用。RCu

iswoundwithcopperwire,whichisinthesametemperatureenvironmentasthecoldendofthethermocouple,andplaystheroleoftemperature

compensationatthecoldend.通過(guò)調(diào)整RP1動(dòng)觸點(diǎn)可實(shí)現(xiàn)變送器零點(diǎn)遷移。ThezeroshiftofthetransmitterisrealizedbyadjustingtheRP1movingcontact.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

熱電偶溫度變送器輸入電路

Inputcircuitofthermocoupletemperaturetransmitter輸入電路輸出電壓U0的計(jì)算公式為T(mén)heoutputvoltageUoformulaoftheinputcircuitisasfollowsU0=Et+URCu

?

URP1

=Et+I1RCu?

URP1RCu上的壓降URCu為I1RCu，當(dāng)冷端溫度為t0、熱端溫度為t時(shí)，熱電偶輸出熱電勢(shì)Et比標(biāo)準(zhǔn)熱電勢(shì)少E(t0,0)，因此需通過(guò)ΔUΔRCu=E(t0,0)進(jìn)行補(bǔ)償，進(jìn)而可據(jù)此計(jì)算出補(bǔ)償電阻RCu的大小。Where,thevoltagedropURCuacrossRCuisI1RCu.Whenthecoldendtemperatureist0andthehotendtemperatureist,sincethethermoelectricpotentialEtoutputbythethermocouplewillbeE(t0,0)lessthanthestandardthermoelectricpotential,itshouldbecompensatedbyΔUΔRCu=E(t0,0),andthevalueofthecompensationresistorRCucanbecalculatedaccordingly.U0=Et+URCu?URP1=Et+I1RCu?URP1Workingprincipleoftemperaturetransmitter溫度變送器的工作原理如果儀表測(cè)量起點(diǎn)定為0℃，當(dāng)熱電偶冷端溫度為0℃,熱端溫度也為0℃時(shí)，Et=0，可調(diào)整電位器RP1，使0℃時(shí)輸入電路輸出電壓U0放大后，變送器輸出電流為起點(diǎn)4mA。Whenthetemperatureofthecoldendofthethermocoupleis0℃andthetemperatureofthehotendisalso0℃ifthemeasurementstartingpointoftheinstrumentissetat0℃,Et=0,thepotentiometerRP1canbeadjustedsothattheoutputcurrentofthetransmitteraftertheoutputvoltageU0oftheinputcircuitisamplifiedat0℃isthestartingpointof4mA.如果測(cè)量起點(diǎn)不為0℃，假定為500℃，同樣調(diào)整電位器RP1，代入上式計(jì)算后的U0值經(jīng)放大后，使500℃時(shí)變送器輸出電流為起點(diǎn)4mA，這種大幅度的零點(diǎn)調(diào)整稱(chēng)為零點(diǎn)遷移。Ifthemeasurementstartingpointisnot0°C,assumingthatitis500°C,thepotentiometerRP1isadjustedinthesamemanner.AftertheU0valuecalculatedbysubstitutingitintotheaboveformulaisamplified,theoutputcurrentofthetransmitterat500°Cisthestartingpointof4mA.Thislargezeroadjustmentiscalledzeroshift.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理零點(diǎn)遷移和改變放大系數(shù)的方法methodsofzeroshiftandadjustmentoftheamplificationcoefficient壓縮儀表量程，使儀表工作區(qū)間和量程與實(shí)際生產(chǎn)過(guò)程工作溫度區(qū)間一致，從而提高變送器測(cè)量精度。Compresstheinstrumentrange.Thisadjuststheinstrument'sworkingrangeandmeasurementrangetoalignwiththeactualworkingtemperaturerangeoftheproductionprocess,therebyenhancingthemeasurementaccuracyofthetransmitter.例如某熱電偶溫度變送器輸出標(biāo)準(zhǔn)信號(hào)為DC4~20mA，標(biāo)準(zhǔn)設(shè)定測(cè)量溫度范圍為0~1500°C，但某生產(chǎn)過(guò)程工作溫度僅在500~1000°C

間變化，直接使用該變送器會(huì)造成測(cè)量區(qū)間浪費(fèi)。Forexample,AthermocoupletemperaturetransmitteroutputsastandardsignalofDC4~20mA,andthemeasurementtemperaturerangesetinthestandardis0~1,500℃.Theworkingtemperatureofacertainproductionprocessonlyvariesbetween500and1,000°C.Usingthistransmitterdirectlywillcausewasteofmeasurementinterval.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理溫度/℃Temperature/℃溫度/℃Temperature/℃溫度/℃Temperature/℃變送器輸出電流隨溫度在0~1500°C范圍內(nèi)變化。Inwhichtheoutputcurrentofthetransmittervarieswiththetemperatureintherangeof0~1500°C.a.未遷移a.Noshift使輸出電流對(duì)應(yīng)溫度范圍發(fā)生改變。Causingtheoutputcurrenttocorrespondtoadifferenttemperaturerange.b.零點(diǎn)正向遷移（調(diào)整RP1）b.Zeropositiveshift(adjustRP1)讓變送器輸出電流更精準(zhǔn)地對(duì)應(yīng)500~1000°C的實(shí)際工作溫度區(qū)間，從而提高測(cè)量精度。Causingtheoutputcurrentofthetransmittermoreaccuratelycorrespondingtotheactualworkingtemperaturerangeof500~1,000°C,therebyimprovingmeasurementaccuracy.c.零點(diǎn)正向遷移(調(diào)整RP1)縮小量程(調(diào)整RP2)c.Zeropositiveshift(adjustRP1)Reducerange(adjustRP2)Workingprincipleoftemperaturetransmitter溫度變送器的工作原理由于熱電偶輸出熱電勢(shì)為微小電壓信號(hào)，放大電路需采用高增益低漂移運(yùn)算放大器，并采取抗干擾措施。Thethermoelectricpotentialoutputbythethermocoupleisatinyvoltagesignal.

Theamplificationcircuitmustadoptahigh-gainandlow-driftoperationalamplifierwhileimplementinganti-interferencemeasures.放大電路Amplificationcircuitucm

變送器受到共模干擾ucm的影響

Thetransmitterisaffectedbycommon-modeinterferenceucm

耐火材料的漏電阻與漏電容Leakageresistanceandleakagecapacitanceofrefractorymaterials.將變送器懸空（不接地），可使uAB=0，消除差模干擾。Atthistime,thetransmitterissuspended(ungrounded),uAB=0,andthedifferentialmodeinterferenceiseliminated,Workingprincipleoftemperaturetransmitter溫度變送器的工作原理反饋電路要完成量程調(diào)整和非線性校正兩個(gè)功能。Thefeedbackcircuitshouldcompletetwofunctions:rangeadjustmentandnonlinearcorrection.反饋電路Feedbackcircuit量程調(diào)整通過(guò)調(diào)整反饋電位器RP2改變放大系數(shù)實(shí)現(xiàn)；TherangeadjustmentisrealizedbyadjustingthefeedbackpotentiometerRP2tochangetheamplificationfactor;非線性校正則借助非線性反饋校正網(wǎng)絡(luò)達(dá)成。Thenonlinearcorrectionisachievedbymeansofanonlinearfeedbackcorrectionnetwork.工作流程

TheworkflowisasfollowsEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路

Powersupplycircuit輸入電路Inputcircuit

輸出電路

Outputcircuit

反饋電路

FeedbackcircuitEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路

Powersupplycircuit輸入電路Inputcircuit

輸出電路

Outputcircuit

反饋電路

Feedbackcircuit輸入電路處理熱電偶信號(hào)TheinputcircuitprocessesthethermocouplesignalEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路

Powersupplycircuit輸入電路Inputcircuit

輸出電路

Outputcircuit

反饋電路

Feedbackcircuit放大電路對(duì)信號(hào)進(jìn)行放大TheamplificationcircuitamplifiesthesignalEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路

Powersupplycircuit輸入電路Inputcircuit

輸出電路

Outputcircuit

反饋電路

Feedbackcircuit反饋電路實(shí)現(xiàn)量程調(diào)整和非線性校正ThefeedbackcircuitrealizesrangeadjustmentandnonlinearcorrectionEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路

Powersupplycircuit輸入電路Inputcircuit

輸出電路

Outputcircuit

反饋電路

Feedbackcircuit輸出電路輸出4-20mA直流信號(hào)及1-5V電壓信號(hào)Theoutputcircuitoutputsa4-20mADCsignalanda1-5VvoltagesignalEtDDZ-III型熱電偶溫度變送器的簡(jiǎn)化電路圖

ThesimplifiedcircuitdiagramofDDZ-IIIthermocoupletemperaturetransmitter.Workingprincipleoftemperaturetransmitter溫度變送器的工作原理

放大電路

Amplificationcircuit

電源電路