Temperature compensation of cold junction of thermocouple sensor

Since the materials of thermocouples are generally more expensive (especially when precious metals are used), and the distance between the temperature measurement point and the instrument is very long, in order to save thermocouple materials and reduce costs, compensation wires are usually used to connect the cold end of the thermocouple (free End) extend into the control room where the temperature is relatively stable, and connect to the terminal of the instrument. It must be pointed out that the function of the thermocouple compensation wire is only to extend the hot electrode and move the cold end of the thermocouple to the instrument terminal of the control room. By itself, it cannot eliminate the influence of the temperature change of the cold end on the temperature measurement and cannot compensate. Therefore, other correction methods are needed to compensate for the influence of the cold junction temperature t0≠0°C on the temperature measurement. When using the thermocouple compensation wire, you must pay attention to the matching of the model, the polarity can not be wrong, and the temperature of the compensation wire and the thermocouple connection end can not exceed 100 ℃.