Location for setting thermocouple compensation temperature
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The field thermocouples are connected to the junction box via compensation cables, from where the signals are sent to the DCS. Currently, the DCS thermocouple acquisition module uses compensated thermoresistors; is it necessary to connect compensation resistors at the field junction box as well, or must compensation cables be used there?
It is necessary to use compensating cables at the on-site junction box, as it ensures the accuracy of temperature readings throughout the entire signal transmission process from the thermocouple to the DCS. The compensation cables gathered in the junction box can effectively compensate for any errors that may arise due to temperature changes during signal transmission. If a compensating thermistor is already used on the DCS side, it is generally no longer necessary to connect a compensating resistor at the junction box. The main goal is to ensure that the cable running from the thermocouple to the DCS system is a compensation cable, in order to guarantee accurate data transmission. .
The function of the compensation wire for a thermocouple is to act as an extension of the thermocouple itself. To ensure accurate measurements, it is necessary to keep the temperature at the cold end of the thermocouple constant, which allows for more precise compensation of that temperature. Therefore, a compensation wire is still required to connect the field wiring terminal to the control room.
With temperature control modules, DCS cards can be standardized, and cables can also be standardized