一种基于国产芯片的热电偶断线检测方法

A Method of Thermocouple Broken Wire Detection Based on Domestic Chip

热电偶作为温度测量仪表中常用的测温元件,具有测温准确度较高、结构简单、动态响应速度快,测温范围较宽等优点,在火电以及化工行业得到了大量的应用。本文就其工作原理以及如何设计基于国产ADC芯片的热电偶测量模件断线检测功能进行了详细的分析,具体方法为通过微处理器、比较器和模拟开关芯片,利用电压基准源,在无恒流源的情况下能够高效地实现现场热电偶信号输入回路的断线检测,既能简化电路缩减硬件成本,又能适配国产化热电偶测量模件,极大地保证了整个控制系统的安全性及可靠性。

As a common temperature measuring element in temperature measuring instruments,thermocouples have the advantages of high temperature measuring accuracy,simple structure,fast dynamic response and wide temperature measuring range,and are widely used in thermal power and chemical industry.This paper gives a detailed analysis of its working principle and how to design the broken line detection function of thermocouple measurement module based on domestic ADC chip.The specific method is to use the voltage reference source through the microprocessor,the comparator and the analog switch chip to efficiently realize the broken line detection of the field thermocouple signal input circuit without a constant current source,which can simplify the circuit and reduce the hardware cost,it can also adapt to the domestic thermocouple measuring module,which greatly ensures the safety and reliability of the entire control system.