Cold Junction

 

The cold junction should be performed after any zero/span calibration.  To perform a cold junction, the corresponding T/C wire will need to be setup on the inputs.  A specific temperature will need to be sourced to the selected input.  The input’s PV value will be displayed on the screen.  Determine the difference between the displayed PV value and the value that is being sourced.

 

For example, assume that input 3 is setup for T/C type K, and 1000 ◦F is being sourced in.  The PV for input 3 is 1002 ◦F.   The value displayed on the cold junction screen is the current temperature of the terminals.  Assume this value is 95.5 ◦F. In the number box, the user would enter a -2 degree difference, or 93.5 ◦F, since the temperature sourced (1000 ◦F) – PV value (1002 ◦F) = -2 ◦F.  Press the Calibrate button to finish off the cold junction calibration.  Return to the main screen to see if the selected input’s PV value is now displaying the correct value of what is being sourced.  If necessary, repeat these steps to further calibrate the cold junction value.