In the process of measurement, if the temperature of the reference end changes, even the temperature range is large, the measurement accuracy of the thermocouple will be seriously distorted. In order to stabilize the reference end and eliminate the distortion caused by the reference end, it is necessary to compensate the reference end; on the other hand, the thermocouple is generally expensive, and the distance from the temperature measuring point to the temperature measuring instrument is usually short. In order to reduce the cost and save the thermocouple, the compensation wire is usually used to connect the reference end to the control room with constant temperature, and then to the temperature measuring instrument.

According to GB / t4989-2013, compensation conductors are divided into two types: extension cables (E) and compensating cables (c). The former can only extend the reference end, and can not eliminate the influence when the reference end is not equal to 0 ° C; the latter can not only extend the reference end, but also eliminate the temperature measurement error caused by the reference end is not equal to 0 ° C. The compensation wire must be used with its matching thermocouple.

The hardware of the 16 channel temperature measurement system includes industrial computer, data acquisition card, display, etc.