RJC of TC Input
As the measurement terminal of the MV is generally at room temperature, the actual
output of the thermocouple is different from the values given on the thermoelectromotive
force table based on 0°C. The MV performs compensation by measuring the temperature
at the input terminal and adding the corresponding thermoelectromotive force to the
actual output of the thermocouple. Therefore, when the measurement terminal is shorted
(equivalent to the case when the detector tip is 0°C), the measured value indicates the
temperature of the input terminal.
When calibrating the MV, this compensation voltage (thermoelectromotive force of 0°C
reference corresponding to the input terminal temperature) must be subtracted from the
output of the standard generator before application. As shown in the figure, by using the
0°C standard temperature device to compensate the reference junction at 0°C, you can
input the thermoelectromotive force of 0°C reference from the DC voltage standard and
perform the calibration.
12.4 Calibrating the MV
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