The use of the thermocouple compensating conductor

Thermocouple compensating lead wires we introduced before, when we were in the use of a large number of thermocouple wire cost consumption is very big, so more saving aspect is the need for compensation conductor, choose these extension wire, alloy wire as they are, in a temperature range is very similar to the net thermoelectric potential of thermocouple itself. In the high temperature section of the measuring circuit can't use this extension of the wire. Can put the extension wire connected to the medium temperature area and the reference points in between the lines. Of course main use of the specific as follows:

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.

thermocouple wires and the corresponding accessories need to combine, and thermocouple materials used to die materials into interface and other metal accessories is better, often use copper wires in side of reference point, and you can buy an alloy solder, the thermocouple potential rate and copper thermoelectric potential rate, so as to minimize thermoelectric potential of local production.