Cold Junction Calibration

 

NOTE: This procedure only applies to thermocouple inputs.  It is not necessary for other voltage inputs.  Perform zero and span calibrations (see previous section) before following this procedure.

 

To determine if a cold junction adjustment is needed, connect the calibrator with the appropriate T/C wire attached and source a temperature to the input. It is best to use an operating temperature to source; for example, if the furnace typically runs at 1000°F, then 1000 °F should be sourced to the input. You may want to source a range of temperatures as this will help determine whether any difference in readings is linear.

 

If the displayed value (PV 1 or PV 2) is not within an acceptable range of the value being sourced, then a Cold Junction Calibration may be necessary. There are two options for calibrating the Cold Junction.