热电偶试验系统误差的纠正方法

Reducing the System Error in the Thermocouple Experiment

热电偶在现代电测温控系统及仪表中应用非常广泛,标定和掌握热电偶的热电势温度特性非常重要。采用K型、E型热电偶为研究对象,试验发现,随温度的改变,热电势的测量结果与参考值相比,有延迟性。为了减小延迟性给标定热电偶的温度特性带来的误差,分升温和降温两个过程测量热电偶的热电势,然后取平均值,结果显示该方法很好地消除了由于延迟性导致的系统误差。

In the modern temperature control systems and electrical instruments, the thermocouples are widely used to measure the temperature. For thermocouples, it is very important to calibrate and understand the temperature characteristics of thermoelectric potential. In this paper, the K-type and E-type thermocouples are used to design experiments and measure the temperature characteristics. It is found that the thermoelectric potential has a certain hysteresis with the change of temperature. In order to reduce the error caused by the hysteresis to the temperature characteristics of the thermocouple, the thermoelectric potential is measured respectively with heating and cooling processes and take the average value. It is found that the system error is effectively reduced by using this method.