Thermocouple cold junction compensation

Thermocouple cold end temperature compensation in industrial production, due to the thermocouple material are relatively expensive, especially when using precious metals, but temperature measuring point to the instrument in the distance, the distance between the thermocouple materials to save and reduce production cost, usually using compensation conductor should be extended the free end of the cold junction of the thermocouple to be stable temperature control room, finally connected to the meter terminals. Must pay attention to the matter, thermocouple compensation function extension hot electrode wire only, to move into the control room of the cold junction of the thermocouple meter terminal, it itself does not remove the cold end temperature change on the influence of temperature, can't act as compensation. So, still need to use other correction method to compensate of the cold end temperature t0 indicates influence on measuring temperature 0 ℃.

must pay attention to when using thermocouple compensating conductor model matching, absolutely can't wrong, it's important to compensate to the wire connected to the thermocouple temperature should not exceed 100 ℃, otherwise it will affect the normal production operation.

platinum-rhodium thermocouple principle and selection of

platinum-rhodium thermocouple working principle is: platinum rhodium thermocouple is based on two different components of the two ends of synthesis loop conductor, when the two junction temperature is not at the same time, will produce thermal current in the circuit. If with the work of the reference junction of the thermocouple, when there is a difference in temperature display instrument will indicate the thermocouple thermoelectric potential corresponding temperature value.

platinum-rhodium thermocouple choice: measure the normal temperature during 1200 ~ 1600 ℃ recommend using double platinum rhodium thermocouple ( Platinum rhodium - 30 Platinum rhodium (6) , measure the normal temperature during 1000 ~ 1300 ℃ suggest using single platinum-rhodium thermocouple ( Platinum rhodium - 10 Platinum) , so in the operating temperature range to guarantee the operation life of platinum-rhodium thermocouple, improve the quality of the products.