West Control Solutions MRC 7000 Controller Manual - Manual (Page 48)

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Error recovery:
See section 5.6 (page 55) for details. Ensure that the millivolt source is connected correctly
and functioning properly.
The calibration can be exited when hLd1 or the calibration reference number is displayed by
pressing the SCROLL key.
CAL2 QUICK CALIBRATION
This routine will allow the operator to execute a rough calibration on their unit via the keypad
with no other equipment or disturbance to established wiring. It is intended to provide a partial
recovery from a calibration corruption where the necessary equipment indicated may not be
available. It should be noted that this is not intended as a substitution to the main calibration
procedure described earlier and may considerable deter from the accuracy of the instrument.
With CAL2 displayed, press and hold the DOWN ARROW key, then press the SCROLL key.
Release both keys and the instrument will display hLd1. Press and hold the UP ARROW key,
then press the SCROLL key. The display will momentarily blank and then CAL1 will be
displayed. Release both keys and depress the UP ARROW key. CAL will be displayed.
5.4.3 CAL 3 COLD JUNCTION COMPENSATION
This routine determines and saves calibration values which correct for component variations
relating to the cold junction compensation. This calibration must be preceded by CAL 2 the
main calibration, to properly calibrate the instrument. These two calibrations are all that is
needed for proper operation with thermocouple inputs
Test equipment: 1-type J thermocouple
1-mercury thermometer +/-.25 degrees F for equivalent
Allow 30 minutes of warm up time for the instrument with the thermocouple
connected before proceeding with calibration.
Operation:
With CAL 3 displayed press and hold the DOWN key, then press the SCROLL key . The
instrument will display hoLd. Release both keys. Press the DOWN key , deLy will be dis-
played for up to 10 seconds, then SCAn for 10 seconds. If SCAn remains in the display for
much longer than ten seconds, refer to the note below. The instrument will compute and
display the cold junction temperature to the nearest tenth of a degree C. Compare the display
reading with thermometer and use the UP and DOWN keys to correct the reading. To exit,
press the SCROLL key and CAL 3 will be displayed again.
NOTE: If the display stays in SCAn for more than 10 seconds press the SCROLL key.
CAL3 should be displayed. With CAL3 displayed, while pressing the DOWN key, press the
SCROLL key. The instrument will display hoLd. Press the UP key. The instrument will
begin the calibration procedure with a default value and proceed to dELy as described
above.
Error recovery:
See section 5.6 (page 55) for details on specific errors. The calibration can be exited if hoLd
or the CJC temperature is displayed by pressing the SCROLL Key.
5.4.4 CAL 4 COLD JUNCTION UTILITY
This procedure displays the temperature the cold junction compensator is sensing. No test
equipment is required.
With CAL 4 displayed, press and hold the DOWN key, then press the SCROLL key . Release
both keys and SCAn will be displayed for 10 seconds while the instrument senses the CJC
temperature. The result will then be displayed to a tenth of a degree C. The input terminals
must be shorted. CAL 3 must first be performed.
The displayed temperature is not the
ambient temperature. It is the temperature of the CJC . To exit, press the SCROLL key
and CAL 4 will be displayed.