9.2.2 To Adjust Cold Junction Compensation (CJC)

 

Thermocouples are calibrated by following the previous procedure for the mV ranges (Section 9.2.1), then calibrating the CJC. Set ‘P1’ to J thermocouple type and verify that the temperature units of measurement is set for degrees Celsius. It is important to ensure P3 (Low Scale) & P4 (High Scale) ranges have been set for the J T/C type.

 

Connect a J T/C source as described in section 9.1.3. Set the mV source to ‘internal compensation’ for the thermocouple in use and set the output of the mV source to 0mV. If your sourcing device does not have this feature then set it to source 0.0 degrees Celsius to the instrument on the V+ and V- terminals.

 

Then:-

 

Operation	Do This	Display View	Additional Notes
Select calibration phase	1.        Press or to select ‘PHAS’		This is found towards the end of the list of ‘P’ codes
Select CJC calibration	2.        Press or to select ‘CJC’
Calibrate CJC	3.        Press to select ‘GO’ 4.        Press or to choose ‘YES’ 5.        Press to confirm 6.        Press again to confirm and to exit from the calibration phase		The controller automatically calibrates to the CJC input at 0mV. The display will show busy then pass, (if calibration is successful) or ‘FAIL’ if not. Fail may be due to an incorrect input mV