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Selection and precautions for compensation wires

Time:2019-02-22 View:79

1, compensation wire selection

The compensation wire must be correctly selected according to the type of thermocouple used and the occasion of use. For example, the k pair should select the compensation wire of the k pair, and then select the operating temperature range according to the use occasion.


2. Connect the contact

Keep the two contacts of the thermocouple terminal as close together as possible, and then keep the temperature of the two contacts similar. Make the temperature of the instrument terminal connection as consistent as possible, and where there is a fan in the instrument cabinet, the contact should be protected and do not let the fan blow directly to the contact, otherwise it will bring unnecessary trouble.

3. Length of use

Because the signal of the thermocouple is very low, it is at the microvolt level, if the distance is too long, the signal will be attenuated by the lengthening of the length and the interference of strong electricity in the environment, which is enough to lead to the signal distortion of the thermocouple, resulting in inaccurate measurement and control of temperature, and temperature fluctuations will occur in serious control.

According to our experience, it is usually better to use the length of the thermocouple compensation wire to control within 15 meters, if more than 15 meters, it is recommended to use a temperature transmitter to transmit signals. The temperature transmitter converts the potential value corresponding to the temperature into direct current transmission, which has strong anti-interference.

4. Wiring position

Compensation wire wiring must be away from power lines and interference sources. Where crossing cannot be avoided, it is also possible to use a cross way, not parallel.

5. Shield compensation wire

In order to improve the anti-interference of thermocouple wire, shielding compensation wire can be used. For the occasions with more on-site interference sources, the effect is better. However, the shielding layer must be strictly grounded, otherwise the shielding layer not only does not play a shielding role, but enhances the interference.