基于AD590的热电偶冷端方法优化设计  

Optimized design of thermsocouple cold junction compensation method based on AD590

作　　者：李亚政 甄国涌[1,2] 贾兴中[1,2] 樊虎 陈冲冲 Li Yazheng;Zhen Guoyong;Jia Xingzhong;Fan Hu;Chen Chongchong(State Key Laboratory of Electronic Testing Technology,North University of China,Taiyuan 030051,China;Key Laboratory of Instrument Science and Dynamic Testing,Ministry of Education,North University of China,Taiyuan 030051,China;The Third Military Representative Office of Air Force Equipment Department in Beijing,Beijing 100710,China)

机构地区：[1]中北大学电子测试技术国家重点实验室,太原030051 [2]中北大学仪器科学与动态测试教育部重点实验室,太原030051 [3]空装驻北京地区第三军代室,北京100710

出　　处：《电子测量技术》2021年第12期156-160,共5页Electronic Measurement Technology

基　　金：国家重点研发计划(2018YFF01010500)项目资助。

摘　　要：为了确保测量温度的准确性,需要对热电偶电路进行冷端补偿。目前使用AD590对热电偶测温进行冷端补偿时,存在电路不对称与安全性不高等问题。本设计针对S型热电偶的冷端补偿进行优化,将热电偶输入电路与AD590冷端补偿电路进行分离,冷端补偿电路输出电压作为偏置电压与热电偶信号叠加,并对叠加后的信号进行放大、滤波等调理。测试结果表明,优化后的电路共模抑制比提高了约50 dB,冷端补偿精度控制在±0.20%FS范围内,可以提高热电偶输入电路的对称性与安全性。In order to ensure the accuracy of the temperature measurement, it is necessary to perform cold junction compensation on the thermocouple circuit. At present, when using AD590 to perform cold junction compensation for thermocouple temperature measurement, there are problems such as circuit asymmetry and low safety. This design is optimized for the cold junction compensation of the S-type thermocouple. The thermocouple input circuit is separated from the AD590 cold junction compensation circuit. The output voltage of the cold junction compensation circuit is used as the bias voltage to superimpose the thermocouple signal, and the superimposed signal perform amplification, filtering and other conditioning. The test results show that the common mode rejection ratio of the optimized circuit is increased by about 50 dB, and the cold junction compensation accuracy is controlled within ±0.20%FS, which can improve the symmetry and safety of the thermocouple input circuit.

关 键 词：热电偶 冷端补偿电路 AD590 

分 类 号：TN212[电子电信—物理电子学]