MEATEST, s.r.o.
M-142 Multifunction Calibrator
User Manual v54
37
Automatic compensation of cold junction temperature
Automatic cold junction TC sensors compensation can be performed, when cable adapter Option 140-01 is used
for simulating. Ambient temperature measured by in cable adapter mounted Pt1000 sensor is taken as
temperature of cold junction. This automatic compensation is performed always, when measuring of ambient
temperature is activated on display (push button INPUT ON, green led lights). When temperature measuring is
not activated or cable adapter Option 140-01 is not connected, manual compensation only is available. Set value
of RJ on the display to the appropriate ambient temperature to compensate manually influence of cold junction.
Use of AUTOCAL function
To remove the effects of short-term drift and thermal dependency of the simulation, AUTOCAL function can be
used. It can only be activated in the calibration mode. Procedure is following:
•
Use a display button to enter the calibration menu. Enter the calibration code and confirm by pressing
ENTER.
•
Use the cursor buttons or potentiometer to select the AUTOCAL function from the calibration menu. After
the function is activated, only one option - OFFSET ACAL - is provided. Press SELECT display button to
confirm the option.
•
Proceed according to the instructions provided on the display. Automatic calibration takes ca 8-10 minutes
and prompts the user to short Hi-Lo circuits and then to disconnect them.
•
After the calibration, the calibrator remains in the calibration mode. Press EXIT display button to return to
normal display.
Do not connect anything to any terminals during the automatic calibration, with the exception of the prompt to
short the Hi-Lo terminals. The procedure is described in “Calibration mode” chapter.
