Since the material of the thermocouple is generally relatively valuable (especially when the metal is used), and the distance from the temperature measurement point to the instrument is very far, in order to save the thermocouple material and reduce the cost, the compensation wire is usually used to extend the cold end (free end) of the thermocouple to the control room where the temperature is relatively stable and connected to the instrument terminal. It must be pointed out that the role of the thermocouple compensation wire only extends the hot electrode, so that the cold end of the thermocouple moves to the instrument terminal in the control room, which itself cannot eliminate the influence of the cold end temperature change on the temperature measurement, and does not compensate. Therefore, other correction methods should be used to compensate the influence of cold end temperature t0≠0℃ on temperature measurement.

When using the thermocouple compensation wire, you must pay attention to the model match, the polarity can not be connected wrong, and the temperature of the compensation wire and the thermocouple connection can not exceed 100℃.