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Numéro de publicationCN103542954 B
Type de publicationOctroi
Numéro de demandeCN 201310470168
Date de publication9 déc. 2015
Date de dépôt10 oct. 2013
Date de priorité10 oct. 2013
Autre référence de publicationCN103542954A
Numéro de publication201310470168.4, CN 103542954 B, CN 103542954B, CN 201310470168, CN-B-103542954, CN103542954 B, CN103542954B, CN201310470168, CN201310470168.4
Inventeurs章伟杰, 朱武亭, 张文
Déposant上海发电设备成套设计研究院
Exporter la citationBiBTeX, EndNote, RefMan
Liens externes:  SIPO, Espacenet
一种高精度的热电偶输入模块及测量方法 A high-precision thermocouple input module and measurement methods Langue du texte original : Chinois
CN 103542954 B
Résumé  Langue du texte original : Chinois
本发明涉及一种高精度的热电偶输入模块,包括隔离器、放大器、模数转换单元、控制器、数模转换单元及电子开关,隔离器与热电偶相连,放大器的输出端模数转换单元,模数转换单元的输出端连接控制器,其特征在于:隔离器的接地端在接地的同时向外引出接地接口,隔离器的电压输出端同时向外引出两个接口,控制器根据由模数转换单元获得的信号向数模转换单元输出反馈信号,数模转换单元的输出端向外引出输出接口。 The present invention relates to a high-precision thermocouple input module, including isolators, amplifiers, analog-digital conversion unit, a controller, digital-analog conversion unit and electronic switches, isolators and thermocouple connected, the output of the amplifier analog to digital conversion unit , the output of analog to digital conversion unit connected to a controller, wherein: ground isolator interfaces leads to the ground outside the ground at the same time, the voltage output of the isolator, while outwardly leads to two interfaces, the controller according to the mold signal digital conversion unit to obtain a feedback signal to the digital-analog conversion unit output, the output of the digital-analog conversion unit outwardly leads output interface. 本发明的另一技术方案是提供了一种高精度的热电偶输入测量方法,采用上述的热电偶输入模块。 Another aspect of the present invention is to provide a highly accurate thermocouple input measurement method using the above-mentioned thermocouple input module. 本发明的优点是:保证热电偶信号整体绝对精度在0.1~0.2℃,相对精度能达到0.005~0.01%,能够满足工业控制过程的真正需要。 Advantages of the present invention are: to ensure absolute accuracy thermocouple signal overall 0.1 ~ 0.2 ℃, relative accuracy can reach 0.005% to 0.01%, to meet the real needs of the industrial control process.
Revendications(3)  Langue du texte original : Chinois
1.一种高精度的热电偶输入模块,包括隔离器、放大器、模数转换单元(ADC)、控制器、数模转换单元(DAC)及电子开关,隔离器与热电偶相连,放大器的输出端连接模数转换单元(ADC),模数转换单元(ADC)的输出端连接控制器,其特征在于:隔离器的接地端在接地的同时向外引出接地接口(4),隔离器的电压输出端同时向外引出两个接口,分别为第一电压输出接口( I)及第二电压输出接口( 3 ),控制器根据由模数转换单元(ADC)获得的信号向数模转换单元(DAC)输出反馈信号,数模转换单元(DAC)的输出端向外引出输出接口( 2 ),通过电子开关的动作使得放大器的同相输入端(SA)与第一电压输出接口(I)连接,同时放大器的反相输入端(SB)与接地接口(4)连接,或者使得放大器的同相输入端(SA)与输出接口(2)连接,同时放大器的反相输入端(SB)与接地接口(4)连接,或者使得放大器的同相输入端(SA)与输出接口( 2 )连接,同时放大器的反相输入端(SB )与第二电压输出接口( 3 )连接; 所述放大器为可编程运算放大器; 所述电子开关共有两个,均为单刀双掷电子开关。 A high-precision thermocouple input module, including isolators, amplifiers, analog-digital conversion unit (ADC), the controller, digital-analog conversion unit (DAC) and electronic switches, isolators and thermocouple connected to the output of the amplifier end analog to digital conversion unit (ADC), analog to digital conversion unit (ADC) connected to the output controller, wherein: ground isolator drawn out of the ground at the same time grounding connector (4), isolation voltage while the output of outwardly leads to two interfaces, respectively, a first voltage output interface (I) and a second voltage output interface (3), the controller based on signals from the analog to digital conversion unit (ADC) to acquire digital-analog conversion unit ( DAC) output feedback signal, digital-analog conversion unit (DAC) of the output of externally derived output interface (2), by the operation of the electronic switch allows the amplifier inverting input terminal (SA) of the first voltage output interface (I) is connected, while the inverting input of the amplifier (SB) and the ground connector (4) is connected, or so-inverting input of the amplifier (SA) and the output interface (2) is connected, while the inverting input of the amplifier (SB) and ground interfaces ( 4) connection, or so-inverting input of the amplifier (SA) and the output interface (2) is connected, while the inverting input of the amplifier (SB) and the second voltage output interface (3); said amplifier is a programmable operation amp; the electronic switch has two, both SPDT electronic switch.
2.如权利要求1所述的一种高精度的热电偶输入模块,其特征在于:所述模数转换单元(ADC)和所述数模转换单元(DAC)选用12位精度的转换器。 2. A high-precision thermocouple input module according to claim 1, characterized in that: the analog to digital conversion unit (ADC) and the digital-analog conversion unit (DAC) 12-bit precision converter.
3.一种高精度的热电偶输入测量方法,采用如权利要求1所述的热电偶输入模块,其特征在于,步骤为: 第一步、操作电子开关,使得放大器的同相输入端(SA)与第一电压输出接口(I)连接,同时放大器的反相输入端(SB)与接地接口(4)连接,将放大器的放大倍数设置为A,控制器获得模数转换单元(ADC)的输出电压Vp的初始值,根据输出电压Vp的初始值及其对应的温度Tp,将热电偶输入模块的上限量程值定义为Tp+A°C,下限量程值定义为Tp-AtC,根据分度号查表找到与Tp+A°C相对应的热电动势VO ; 第二步、操作电子开关,使得放大器的同相输入端(SA)与输出接口(2)连接,同时放大器的反相输入端(SB )与接地接口( 4 )连接,调整控制器的反馈电压Vf,使得输出接口( 2 )上的参考电压Vref= VO+Δ 1,Δ I为放大器及模数转换单元(ADC)的输入综合误差; 第三步、操作电子开关,使得放大器的同相输入端(SA)与输出接口(2)连接,同时放大器的反相输入端(SB)与第二电压输出接口(3)连接,将放大器的放大倍数设置为B,B远大于Α,此时,放大器的同相输入端(SA)上的参考电压Vref= VO+Δ 1,放大器的反相输入端(SB)上的电压为隔离器的输出电压Vi,端差值为V0+Al-Vi,减去放大器及模数转换单元(ADC)的输入综合误差Δ I后,最终模数转换单元(ADC)的输出电压Vp=VO+Δ 1-V1-Δ 1=VO-Vi,该热电动势对应的温度Ti,则最终的温度值为Tp+A-Ti。 3. A high-precision measurement thermocouple input, thermocouple input module as claimed in claim 1, characterized in that the steps of: a first step, the operation of electronic switches, so that the noninverting input terminal of the amplifier (SA) connected to a first voltage output interface (I), while the inverting input of the amplifier (SB) and the ground connector (4) is connected to the amplifier magnification is set to A, the controller output is obtained analog to digital conversion unit (ADC) of The initial value of the voltage Vp, according to the initial value of the output voltage Vp and the corresponding temperature Tp, the upper range value is defined thermocouple input module is Tp + A ° C, the lower limit of the range value is defined as Tp-AtC, in accordance with sub-degree No. lookup to find and Tp + A ° C corresponding to a thermal electromotive force VO; the second step, operating the electronic switch so that the amplifier inverting input terminal (SA) and the output interface (2) is connected, while the inverting input of the amplifier (SB ) and ground connector (4) is connected, adjust the controller feedback voltage Vf, so that the output interface (reference voltage Vref 2) on = VO + Δ 1, Δ I amplifier and analog-to-digital conversion unit (ADC) input integrated error ; the third step, operation of the electronic switch so that the amplifier inverting input terminal (SA) and the output interface (2) is connected, while the inverting input of the amplifier (SB) and the second voltage output connector (3) connected to the amplifier Magnification is set to B, B is much larger than Α, at this time, the amplifier inverting input terminal reference voltage Vref (SA) on = VO + Δ 1, voltage at the inverting input of the amplifier (SB) on the isolator output voltage Vi, the difference between the end of V0 + Al-Vi, subtracting amplifier and analog-digital conversion unit (ADC) input of the integrated error Δ I, the final analog-digital conversion unit (ADC) output voltage Vp = VO + Δ 1- V1-Δ 1 = VO-Vi, the thermoelectromotive force corresponding to the temperature Ti, the final temperature value Tp + A-Ti.
Description  Langue du texte original : Chinois
一种高精度的热电偶输入模块及测量方法 A high-precision thermocouple input module and measurement methods

技术领域 TECHNICAL FIELD

[0001] 本发明涉及一种高精度的热电偶输入模块及测量方法,用于提高热电偶或毫伏等小信号的测量精度,属于自动控制仪表技术领域。 [0001] The present invention relates to a high-precision thermocouple input module and the measuring methods used to improve the accuracy of thermocouple or millivolt signals and other small, automatic control instruments belonging to the technical field.

背景技术 Background technique

[0002] 热电偶是由两种不同成份的金属线在其端部连接以形成闭合回路,直接用作测量介质温度的一端叫做工作端(也称为测量端),另一端叫做冷端(也称为补偿端),当工作端与冷端之间存在温度差时,回路中就会有电流通过,此时两端之间就存在热电动势(塞贝克效应),根据情况选择不同的金属材质便会得出大约与温度差成比例的电压输出。 [0002] Thermocouple wire is composed of two different components connected at their ends to form a closed circuit, as a direct measurement of the medium temperature is called the end of the working end (also referred to as measuring end), and the other end is called the cold end (also called compensation side), when there is between the working end and the cold end temperature difference, there will be current through the loop, then there is the thermal electromotive force (Seebeck effect) between the two ends, depending on the circumstances choose a different metal it will come about with the temperature difference is proportional to the voltage output. 但是这个电压都很非常小,例如比较最常见的镍铬-镍硅K分度热电偶-270 °C〜1372 °C对应的热电势为-6.458mV〜54.886mV,镍铬-铜镍合金E分度热电偶_270°C〜1000°C对应的热电势为-9.835mV 〜76.373mV。 However, this voltage is very very small, for example, comparing the most common nickel-chromium - nickel silicon thermocouple of K -270 ° C~1372 ° C corresponding to the thermoelectric power is -6.458mV~54.886mV, nickel-chromium - copper-nickel alloy E indexing thermocouple _270 ° C~1000 ° C corresponding to the thermoelectric power is -9.835mV ~76.373mV.

[0003] 分散控制系统(DCS)或可编程控制系统(PLC)等控制系统的热电偶输入模块的信号处理方法是获得由热电偶产生的热电动势(毫伏电压信号),将其作为模拟电信号经过放大器放大到伏电压信号,再经由模数转换器(ADC)输入到控制芯片的数字数据中,由控制芯片或交由上位机根据分度号查表或采用温度估算模型公式处理来转换成实际温度。 [0003] The signal processing method for distributed control system (DCS) or programmable control system (PLC) and other control systems thermocouple input module is to obtain thermal emf (mV voltage signal) generated by a thermocouple, which is an analog electrical signals are amplified to volt signal, and then input via the analog to digital converter (ADC) to control the chip's digital data, the control by the host computer based on chips or indexing number look-up table or the use of temperature estimation process to convert the model formula into the actual temperature.

[0004] 早期由于半导体技术相对落后,为了克服控制芯片处理速度慢且存储器容量小的问题,采用各种各样的温度估算模型公式来处理。 [0004] Early As the semiconductor technology is relatively backward, in order to overcome control chip processing speed and less memory capacity problems, using a variety of formulas to deal with the temperature estimation model. 随着控制芯片处理速度和存储容量的技术指标大幅度的提升,采用最原始的查表来克服温度估算模型公式与实际温度的微小的误差。 With greatly enhanced control chip processing speed and storage capacity Technical indicators using the most primitive look-up table to overcome the small temperature error model estimation formula and the actual temperature.

[0005] 从表面上来看,热电偶信号测量精度会集中到模数转换器(ADC)上,一般模数转换器采用12位,虽然模数转换器理论分辨率为1/4096 (即万分之二),但是由于放大器和模数转换器等元器件的参考电压和电阻等元器件的温飘等等原因,实际上整个热电偶信号的测量精度一般为0.1〜0.2%之间,即使有些厂家将模数转换器提高到13位或14位、甚至15位,但整体测量精度并不能提高多少。 [0005] On the surface, the measurement accuracy will focus thermocouple signal to digital converter (ADC), the general 12-bit analog to digital converter, although the ADC theoretical resolution of 1/4096 (ie very bis), but since the reference voltage and resistance components such as amplifiers and ADC components of temperature drift and other reasons, virtually the entire measurement accuracy thermocouple signal is generally between 0.1 to 0.2%, even though some ADC manufacturers will increase to 13 or 14, or even 15, but the overall accuracy did not improve much.

[0006] 在工业过程控制中,这种相对精度对于执行机构的阀位开度、压力、流量、液位、电压电流等等过程变量问题并不大,但是对于温度信号,由于它没有具体的量程范围,一般情况下热电偶输入模块为兼容各种分度号的热电偶信号,采用的热电势信号会有足够的上限裕度,折算成温度量程上限会达到200(TC,这时相对精度折算成绝对值会到2°C〜4°C。而实际上,低温度一般会发生在设备启动过程,当工业过程正常运行时,主要的温度过程参数会在一个较高的温度下进行小幅度的变化。例如600MW超超临界火力发电机组锅炉过热器出口温度在50%额定工况以上时温度基本在560±10°C之间运行,温度变化范围在20°C,而如果作为锅炉安全保护信号使用,跳炉值也仅为597°C,温度变化为+37°C这时2°C〜4°C的绝对误差就显得非常严重。 [0006] In industrial process control, the relative accuracy of the valve opening actuator, pressure, flow, level, voltage, current, and so the process variable problem is not big, but the temperature signal, because it does not specifically range, under normal circumstances thermocouple input module is compatible with all indexing number of thermocouple signals, thermoelectric power signal used in the upper have enough margin, converted into the upper limit of the temperature range will reach 200 (TC, then the relative accuracy It will be converted into an absolute value to 2 ° C~4 ° C. In fact, low temperatures will generally occur in the device startup process, when the normal operation of the industrial process, the temperature of the main process parameters will be small at a higher temperature changes in amplitude. For example 600MW ultra-supercritical thermal power unit boiler superheater outlet temperature when the temperature substantially between 560 ± 10 ° C run at more than 50% of the rated operating conditions, the temperature range at 20 ° C, but if, as the boiler safety protection signal use, jump furnace value is only 597 ° C, the temperature change is + 37 ° C then absolute error 2 ° C~4 ° C it is very serious.

发明内容 SUMMARY OF THE INVENTION

[0007] 本发明要解决的技术问题是保证热电偶信号的精度。 [0007] The technical problem to be solved is to ensure the accuracy of the thermocouple signal.

[0008] 为了解决上述技术问题,本发明的一个技术方案是提供了一种高精度的热电偶输入模块,包括隔离器、放大器、模数转换单元、控制器、数模转换单元及电子开关,隔离器与热电偶相连,放大器的输出端模数转换单元,模数转换单元的输出端连接控制器,其特征在于:隔离器的接地端在接地的同时向外引出接地接口,隔离器的电压输出端同时向外引出两个接口,分别为第一电压输出接口及第二电压输出接口,控制器根据由模数转换单元获得的信号向数模转换单元输出反馈信号,数模转换单元的输出端向外引出输出接口,通过电子开关的动作使得放大器的同相输入端与第一电压输出接口连接,同时放大器的反相输入端与接地接口连接,或者使得放大器的同相输入端与输出接口连接,同时放大器的反相输入端与接地接口连接,或者使得放大器的同相输入端与输出接口连接,同时放大器的反相输入端与第二电压输出接口连接。 [0008] In order to solve the above problems, one aspect of the present invention is to provide a highly accurate thermocouple input module, including isolators, amplifiers, analog-digital conversion unit, a controller, digital-analog conversion unit and an electronic switch, Isolator thermocouple is connected the output of the amplifier analog to digital conversion unit, the output of analog to digital conversion unit to connect the controller, wherein: ground isolator interfaces leads to the ground outside the ground at the same time, the voltage isolation the output of both interfaces simultaneously drawn outwardly, respectively, the first voltage and the second voltage output interface output interface, a controller based on a signal obtained by the analog-digital conversion unit of a feedback signal to the output of the digital-analog conversion unit, the output of digital-analog conversion unit end outwardly leads to the output interface, through the operation of the electronic switch allows the amplifier inverting input terminal and the first voltage output interface, while the interface is connected to the inverting input of the amplifier to ground, or so that the amplifier inverting input terminal and the output interface, while the inverting input of the amplifier and a ground interface, or allows the amplifier inverting input terminal and the output interface, while the inverting input of the amplifier and a second voltage output connector.

[0009] 优选地,所述放大器为可编程运算放大器。 [0009] Preferably, the programmable amplifier is an operational amplifier.

[0010] 优选地,所述电子开关共有两个,均为单刀双掷电子开关。 [0010] Preferably, the electronic switch has two, both SPDT electronic switch.

[0011] 优选地,所述模数转换单元和所述数模转换单元选用12位精度的转换器。 [0011] Preferably, the analog-digital conversion unit and the digital-analog conversion unit 12-bit precision converter.

[0012] 本发明的另一技术方案是提供了一种高精度的热电偶输入测量方法,采用上述的热电偶输入模块,其基本思路是: [0012] Another aspect of the present invention is to provide a highly accurate thermocouple input measurement method using the above-mentioned thermocouple input module, the basic idea is:

[0013] 降低放大器的放大倍数,预测实际测量温度值后将温度的上下限量程基准点从超大量程范围切片分割成小量程范围。 [0013] reduce the magnification of the amplifier, predict the actual measured temperature after the temperature of the upper and lower limit reference points away from large-scale range of the slice is divided into small range. 控制器利用数模转换器作为反馈端与输入端形成一个闭环回路,调整放大器的参考基准值以克服输入端和反馈端的综合误差。 The controller uses analog converter as the feedback terminal and the input to form a closed loop, adjust the amplifier reference value in order to overcome a comprehensive error reference input and the feedback side. 大幅度提高放大器的放大倍数,结合修正过的放大器的参考基准值,经过控制器的计算得出高精度的热电偶信号对应的温度值特征在于,具体步骤为: Substantial increase in amplification of the amplifier, combined with corrected reference amplifier reference value, has been calculated to draw the controller features high-precision temperature thermocouple signal corresponding to that specific steps:

[0014] 第一步、操作电子开关,使得放大器的同相输入端与第一电压输出接口连接,同时放大器的反相输入端与接地接口连接,将放大器的放大倍数设置为A,控制器获得由模数转换单元的输出电压Vp的初始值,根据输出电压Vp的初始值及其对应的温度Tp,将热电偶输入模块的上限量程值定义为Tp+A°C,下限量程值定义为Tp-AtC,根据分度号查表找到与Tp+A°C相对应的热电动势VO ; [0014] First, operation of the electronic switches, so that the amplifier inverting input terminal connected to the first voltage output interface, while the inverting input terminal and a ground interface amplifier, the amplification of the amplifier is set to A, the controller obtained from The initial value of the output voltage Vp of the analog to digital conversion unit, based on the initial value of the output voltage Vp and the corresponding temperature Tp, the thermocouple input module upper range value is defined as Tp + A ° C, the lower limit of the range value is defined as Tp- AtC, according to indexing number lookup to find and Tp + A ° C corresponding to a thermal electromotive force VO;

[0015] 第二步、操作电子开关,使得放大器的同相输入端与输出接口连接,同时放大器的反相输入端与接地接口连接,调整控制器的反馈电压Vf,使得输出接口上的参考电压Vref=VO+Δ 1,△ I为放大器及模数转换单元的输入综合误差; [0015] The second step, operating the electronic switch so that the amplifier non-inverting input and output connectors, while the inverting input of the amplifier and the ground interface, tuning controller feedback voltage Vf, so that the reference voltage Vref output interface = VO + Δ 1, △ I amplifier and ADC input error means comprehensive;

[0016] 第三步、操作电子开关,使得放大器的同相输入端与输出接口连接,同时放大器的反相输入端与第二电压输出接口连接,将放大器的放大倍数设置为B,B远大于Α,此时,放大器的同相输入端上的参考电压Vref = VO+Δ 1,放大器的反相输入端上的电压为隔离器的输出电压Vi,端差值为VO+Δ 1-Vi,减去放大器及模数转换单元的输入综合误差Δ I后,最终模数转换单元的输出电压Vp = VO+Δ 1-V1-Δ I = VO-Vi,该热电动势对应的温度Ti,则最终的温度值为Tp+A-Ti。 [0016] The third step, operation of the electronic switch, making the amplifier non-inverting input and output connectors, while the inverting input of the amplifier and a second voltage output interface, the amplification of the amplifier is set to B, B is much larger than Α In this case, the amplifier inverting input terminal on the reference voltage Vref = VO + Δ 1, the voltage on the inverting input of the amplifier to the isolator output voltage Vi, end difference of VO + Δ 1-Vi, minus After entering the integrated error amplifier and analog-digital conversion unit Δ I, the output voltage Vp final analog-digital conversion unit = VO + Δ 1-V1-Δ I = VO-Vi, the thermal electromotive force corresponding temperature Ti, the final temperature value Tp + A-Ti.

[0017] 本发明的优点是:保证热电偶信号整体绝对精度在0.1〜0.2°C,相对精度能达到0.005〜0.01%,能够满足工业控制过程的真正需要。 Advantages [0017] The present invention is: to ensure absolute accuracy of the overall thermocouple signal 0.1~0.2 ° C, relative accuracy can reach 0.005~0.01%, to meet the real needs of the industrial control process.

附图说明 Brief Description

[0018]图1为本发明提供的一种高精度的热电偶输入模块示意图。 [0018] FIG. 1 of the present invention to provide a highly accurate thermocouple input module schematic.

具体实施方式 detailed description

[0019] 为使本发明更明显易懂,兹以优选实施例,并配合附图作详细说明如下。 [0019] In order that the invention may be more fully understood, hereby to a preferred embodiment, and the following detailed description with accompanying drawings.

[0020] 如图1所示,本发明提供的一种高精度的热电偶输入模块,包括隔离器、放大器、模数转换单元ADC、控制器、数模转换单元DAC及电子开关,隔离器与热电偶相连,放大器的输出端模数转换单元ADC,模数转换单元ADC的输出端连接控制器,其特征在于:隔离器的接地端在接地的同时向外引出接地接口4,隔离器的电压输出端同时向外引出两个接口,分别为第一电压输出接口I及第二电压输出接口3,控制器根据由模数转换单元ADC获得的信号向数模转换单元DAC输出反馈信号,数模转换单元DAC的输出端向外引出输出接口2,通过电子开关的动作使得放大器的同相输入端SA与第一电压输出接口I连接,同时放大器的反相输入端SB与接地接口4连接,或者使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与接地接口4连接,或者使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与第二电压输出接口3连接。 [0020] As shown, the present invention provides a highly accurate thermocouple input module, including isolators, amplifiers, analog-digital conversion unit ADC, controller, digital-analog conversion unit DAC and electronic switches, isolator 1 and thermocouple connected to the output of analog to digital conversion unit ADC amplifier, the output of the analog to digital conversion unit ADC connection controller, wherein: ground isolator interface leads to the ground outside the ground, while 4, isolation voltage the output of both interfaces simultaneously drawn outwardly, respectively, the first voltage and the second voltage output interface I output interface 3, a controller based on a signal from the analog-digital conversion unit ADC to obtain digital to analog conversion means DAC output feedback signal, the digital-analog conversion unit DAC output terminal leads outward output interface 2, through the operation of the electronic switch allows the amplifier inverting input terminal SA and the first voltage output interface I connected, while the amplifier 4 is connected to the inverting input terminal and the ground SB interface, or making 2-inverting input of the amplifier is connected to the output terminal SA interface, while the amplifier 4 is connected to the inverting input terminal and the ground SB interface, or allows the amplifier inverting input terminal SA 2 is connected to the output interface, while the inverting input of the first amplifier SB two voltage output interface 3 is connected.

[0021 ] 放大器为可编程运算放大器。 [0021] Operational amplifier is a programmable amplifier.

[0022] 电子开关共有两个,均为单刀双掷电子开关。 [0022] There are two electronic switches, electronic switches are single pole double throw.

[0023] 模数转换单元ADC和所述数模转换单元DAC选用12位精度的转换器,本领域技术人员也可以根据需要选用其他精度的转换器。 [0023] The analog-digital conversion unit ADC and the digital-analog converter DAC selection unit 12 precision converter, skilled in the art may also need to use other precision converters.

[0024] 利用上述模块的热电偶输入测量方法,其步骤为: [0024] With the above thermocouple input module measuring method, comprising the steps of:

[0025] 第一步、操作电子开关,使得放大器的同相输入端SA与第一电压输出接口I连接,同时放大器的反相输入端SB与接地接口4连接,将放大器的放大倍数设置为A,控制器获得由模数转换单元ADC的输出电压Vp的初始值,根据输出电压Vp的初始值及其对应的温度Tp,将热电偶输入模块的上限量程值定义为Tp+A°C,下限量程值定义为Tp-AtC,根据分度号查表找到与Tp+A°C相对应的热电动势VO ; [0025] First, operation of the electronic switch so that the amplifier SA-inverting input of the first voltage output interface I connected, while the inverting input of the amplifier SB interface 4 and the ground connection, the amplification of the amplifier is set to A, obtained from the initial value controller analog-digital conversion unit ADC output voltage Vp, based on the initial value of the output voltage Vp and its corresponding temperature Tp, the upper range value is defined as the thermocouple input module Tp + A ° C, the lower limit of the range value is defined as Tp-AtC, according to indexing number lookup to find and Tp + A ° C corresponding to a thermal electromotive force VO;

[0026] 第二步、操作电子开关,使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与接地接口4连接,调整控制器的反馈电压Vf,使得输出接口2上的参考电压Vref = VO+Δ 1,Al为放大器及模数转换单元ADC的输入综合误差; [0026] The second step, the operation of the electronic switch so that the amplifier inverting input terminal SA 2 is connected to the output interface, while 4 are connected, adjust the controller feedback voltage Vf amplifier inverting input terminal SB and ground interfaces, so that the output connector 2 on the reference voltage Vref = VO + Δ 1, Al amplifier and analog-to-digital conversion unit ADC input integrated error;

[0027] 上述第二步的推导过程为: [0027] The second step of the derivation of the above is:

[0028] 若调整控制器的反馈电压Vf为热电动势V0,则Vref参考电压=VO-A 2,Δ 2为反馈综合误差,则输出电压Vp = Vref- Δ I = VO- Δ 2- Δ I。 [0028] If the tuning controller of the feedback voltage Vf of the thermoelectromotive force V0, the reference voltage Vref = VO-A 2, Δ 2 is the integrated feedback error, the output voltage Vp = Vref- Δ I = VO- Δ 2- Δ I . 若要使得输出电压Vp = V0,则通过反向计算,需要将控制器的输出反馈电压Vf调整为VO+Δ 2+Δ 1,此时,Vref = Vf-A 2=νθ+Δ2+Δ 1-Δ2 = VO+Δ 10 To make the output voltage Vp = V0, the reverse calculation, you need to control the output feedback voltage Vf is adjusted to VO + Δ 2 + Δ 1, at this time, Vref = Vf-A 2 = νθ + Δ2 + Δ 1 -Δ2 = VO + Δ 10

[0029] 第三步、操作电子开关,使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与第二电压输出接口3连接,将放大器的放大倍数设置为B,B远大于Α,此时,放大器的同相输入端SA上的参考电压Vref = VO+Δ 1,放大器的反相输入端SB上的电压为隔离器的输出电压Vi,端差值为VO+ Δ 1-Vi,减去放大器及模数转换单元ADC的输入综合误差AI后,最终模数转换单元ADC的输出电压Vp = VO+ Δ 1-V1-Δ I = VO-Vi,该热电动势对应的温度Ti,则最终的温度值为Tp+A-Ti。 [0029] The third step, operation of the electronic switch allows the amplifier inverting input terminal SA 2 is connected to the output interface, while the inverting input of the amplifier and a second voltage SB output interface 3 is connected, the amplification of the amplifier is set to B, B is much larger than Α, at this time, the amplifier inverting input terminal SA reference voltage Vref on = VO + Δ 1, voltage at the inverting input of the amplifier on SB for the isolator output voltage Vi, end difference of VO + Δ 1 -Vi, after subtracting the integrated error AI input amplifier and the analog-digital conversion unit ADC, analog to digital conversion unit ADC final output voltage Vp = VO + Δ 1-V1-Δ I = VO-Vi, the thermoelectromotive force corresponding to the temperature Ti , the final temperature value Tp + A-Ti.

[0030] 以下结合数据来进一步说明本发明。 [0030] The following binding data to further illustrate the present invention.

[0031] 利用高精度的信号发生器对热电偶输入模块的第一通道输出27.025mV(此热电动势在K分度号对应650°C ),热电偶输入模块的工作过程如下(为便于理解,计算测量值时放大倍数被忽略): [0031] The use of high-precision signal generator to the first channel thermocouple input module output 27.025mV (this thermal emf in K dividing the corresponding 650 ° C), thermocouple input module works as follows (for ease of understanding, When calculating the measured value magnification is ignored):

[0032] 第一步、操作电子开关,使得放大器的同相输入端SA与第一电压输出接口I连接,同时放大器的反相输入端SB与接地接口4连接,设置放大器的放大倍数为50,得到Vp的初始值26.856mV,根据Vp的初始值26.878mV及对应的温度Tp (646.53°C ),将它的上限量程值定义为28.984mV(696.53 °C ),下限量程值定义为24.758mV(596.53°C )。 [0032] First, operation of the electronic switch so that the amplifier SA-inverting input of the first voltage output interface I connected, while the amplifier 4 is connected to the inverting input terminal SB and ground interfaces, set the magnification of the amplifier 50, to give Vp initial value 26.856mV, based on the initial value Vp 26.878mV and corresponding temperature Tp (646.53 ° C), the upper limit of its range is defined as 28.984mV (696.53 ° C), the lower limit of the range value is defined as 24.758mV (596.53 ° C).

[0033] 第二步、操作电子开关,使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与接地接口4连接,控制器的反馈电压Vf为28.984mV,通过输入端得到的Vp为28.704mV,通过反向计算,若要使得Vp为28.984mV,则将控制器的反馈电压Vf设定为29.264mV。 [0033] The second step, operating the electronic switch so that the amplifier inverting input terminal SA 2 is connected to the output interface, while the amplifier 4 is connected to the inverting input of the SB and ground interfaces, controller of the feedback voltage Vf is 28.984mV, by typing end resulting Vp is 28.704mV, through the reverse calculation, to make Vp is 28.984mV, then the controller of the feedback voltage Vf is set to 29.264mV.

[0034] 第三步、操作电子开关,使得放大器的同相输入端SA与输出接口2连接,同时放大器的反相输入端SB与第二电压输出接口3连接,设置放大器的放大倍数为500,此时,Vref为29.131mV,Vi为信号发生器的实际输入27.025mV,端差值为2.106,最终得到Vp为1.959mV,折算最终被测量信号的热电动势为27.025,对应的温度为650°C,测量误差为 [0034] The third step is operating the electronic switches, so that the amplifier 2 connected to the noninverting input terminal SA and the output interface, while the inverting input of the amplifier and a second voltage SB output interface 3 is connected, for setting amplification of the amplifier 500, this When, Vref is 29.131mV, Vi is the actual input 27.025mV signal generator, the difference is 2.106 end, Vp is finally obtained 1.959mV, the measured signal is finally converted thermoelectromotive force of 27.025, the corresponding temperature of 650 ° C, Measurement error is

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Classifications
Classification internationaleG01K7/02
Événements juridiques
DateCodeÉvénementDescription
29 janv. 2014C06Publication
9 déc. 2015C14Grant of patent or utility model