Partlow MRC 7000, Installation & Operation Manual

Page: 37 / 64

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4.4.5 CAL 5 RTD INPUT
This procedure determines and saves calibration values relating to RTD inputs. This calibra-
tion must be preceded by CAL 2 to properly calibrate the instrument. Both RTD inputs must
be calibrated and both inputs must have valid inputs during the calibration. Decade boxes
with .01% resolution or equivalent are required.
Make sure that the Processor board
jumpers JU4, JU6 and JU5, JU7 are in the proper positions. See Appendix A-1 (page
50).
With CAL 5 displayed, press and hold the DOWN key and then press the SCROLL key. The
display will now be PEn1 to indicate that the instrument is set to calibrate the RTD input on
TB 4 . Press the DOWN key to change the display to PEn2 to calibrate the RTD input at TB
5. Choose the input TB to be calibrated and press the SCROLL key, hLd1 will then be
displayed. Connect the decade box at 100 ohm setting across the input terminals 1 and 2 and
a jumper wire from terminal 2 to 3. Press the DOWN key and dELy will be displayed for 10
seconds, then SCAn for ten seconds. When hLd2 is displayed, change the decade box
setting to 277 ohms to the input terminals (do not disturb the wiring) and press the DOWN
key. The display will change to dELy for 10 seconds, followed by SCAn for ten more
seconds. CAL 5 will be displayed after the calibration is completed. To exit the calibration
mode properly, with CAL5 displayed, press the UP key twice. To continue to another
calibration, press the SCROLL key with CAL5 displayed.
Error recovery:
See section 4.6 (page 43) for details on specific errors.
The calibration can be exited when the instrument displays hLd1 by pressing the SCROLL
key.
4.4.6 CAL 6 COLD JUNCTION UTILITY
This routine provides selection of operating modes for the cold junction compensation used
for thermocouple inputs.
With CAL 6 displayed, press and hold the DOWN key, then press the SCROLL key. The
instrument will display C6 and the number of the mode in effect. Press the UP or DOWN key
to change the mode selection, indicated by the number to the right of the C6. Pressing the
SCROLL key will exit the calibration with the last mode number displayed in effect.
The selected mode will remain in effect if power is interrupted. To return the instrument to
normal operation, CAL 6 must be exited, with mode zero selected, or CAL 1 must be exe-
cuted to initialize all parameters.
Mode 0: Normal operating mode.
Mode 1: Cold Junction Compensation temperature will be internally fixed at 0 degrees C by
the software to facilitate linearization testing when using an uncompensated millivolt source to
simulate the thermocouple millivolt input signal .