The selection of compensation wire has a great influence on the accuracy of thermocouple temperature measurement, and instrument operators must be familiar with the performance and indicators of various compensation wires. Next, the main compensation wire use precautions to make a brief introduction.

1. For S type thermocouple and R type thermocouple, there are two kinds of compensation wires SC and RC, both of which belong to compensation type compensation wires, and the accuracy is low in all kinds of compensation wires. The error is small in the range of 0-60 ° C, but there is a large error in the range of 100-150 ° C. If the measurement accuracy is high, the temperature of the compensation contact must be kept below 100 ° C.

2, K type thermocouple compensation wire has KC type and KX type. KX is a extended-type compensation wire, the characteristic curve is linear in a wide temperature range, the error is small, but the cost is high and the resistance is large. Therefore, in the case that the use temperature is not high and the temperature measurement accuracy requirements are not too strict, the cheaper compensation type compensation wire KC type should be used.

Problems to pay attention to when using compensation wires:

1, all kinds of compensation wires can only be paired with the corresponding model of thermocouple, different models can not be used.

2, the compensation wire has positive and negative poles. When used, the positive and negative poles of the compensation wire should not be connected incorrectly, otherwise it will not only fail to compensate, but also cause a large measurement error. It has been proved that the error caused by the wrong polarity of the compensated wire is about twice that of the uncompensated wire.

3, the temperature of the thermocouple and compensation wire connection point shall not exceed the specified use temperature. Because the specified operating temperature is exceeded, the thermoelectric characteristics of the compensation wire and the thermocouple differ greatly, resulting in measurement errors.

4, because the thermoelectric characteristics of the compensation wire and the thermocouple are not exactly the same, the temperature of the two contacts at the connection is required to be the same, otherwise it will cause measurement error.

5, according to the different requirements of the equipped display instrument to choose the diameter of the compensation wire. For example, the compensation wire connected with the moving coil instrument can be selected with a thicker wire diameter, so that its resistance value is smaller, so that it will not exceed the external resistance value specified by the instrument.

6. In order to facilitate installation, multiple strands of compensation wires can be selected, and waterproof, anti-corrosion and fireproof compensation wires can also be selected according to needs.