The role of the thermocouple compensating conductor

Thermocouple compensating thermal electrode wire is to extend the movement of the thermocouple cold end, and display instrument connection temperature measuring system.

choosing thermocouple compensating conductor to know the thermocouple compensation wire environment temperature and the industrial and mining conditions, according to the environment temperature conditions to choose the appropriate compensation wire sheath, general environment temperature in - 25 ~ 105 ℃ when choose PVF sheath, environment temperature in - 60 ~ 205 ℃ when the choice of perfluorinated ethylene as compensation wire sheath, and in - 60 ~ 260 ℃, choose ptfe as the thermocouple compensation wire sheath. So when the choice must pay attention to the mining conditions.

thermocouple compensation wire, to a certain temperature range, Including room temperature) With the matched the thermocouple thermoelectric emfs the nominal value of the same pair with the insulation wire, thermocouple and measuring devices with their connections, to compensate them with the error produced by the temperature change of the thermocouple junction.

compensation conductor should be notice:

1. The choice of the compensating conductor

compensation conductor must according to the type of thermocouple used properly choose and use occasion. K type should I choose k type, for example, accidentally compensating lead wires, according to the using situation, choose the operating temperature range. Usually work temperature for - kx 20 ~ 100 ℃, wide range of for - 25～200℃。 Common error of plus or minus 2. Level 5 ℃, the precision of plus or minus 1. 5℃。

2。 Contact between

and thermocouple closer to terminal 2 contact as soon as possible, try to keep two junction temperature. And meter terminal junction temperature consistent as far as possible, instrument cabinets have a fan, don't make contact place to protect the fan blowing straight to contact.

3。 Using length

because of thermocouple signal is very low, for microvolt level, if you use the distance is too long, the signal attenuation and the interference of high-voltage electrical coupling in the environment, can make the thermocouple signal distortion, cause inaccurate measurement and control temperature, serious when produce temperature fluctuations in the control.

according to our experience, usually use the length of the thermocouple compensation wire control within 15 meters is better, if more than 15 meters, it is recommended to use temperature transmitter to transmit signal. Temperature transmitter is the potential value of the corresponding temperature is converted into direct current stream, strong anti-jamming.

4。 Wiring

the compensating conductor wiring must be far away from power lines and interference sources. Where can't avoid crossing, also adopts cross method, as far as possible not parallel.

5。 Shielding compensation conductor

in order to improve the anti-interference of thermocouple wire, shielding compensation conductor can be used. For the interference sources more occasions, the effect is better. Strictly grounding, but must will shield or shield does not have the effect of shielding, enhance interference instead.