Partlow MRC 7700, Руководство по установке и эксплуатации

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5.4.5 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 resistance
substitution box with .01% resolution or equivalent are required.
Make sure that the Proces-
sor board jumpers JU4, JU6 and JU5, JU7 are in the proper positions. See Appendix A-
1 (page 68).
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. (Continued on next page)
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 138.5 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 calibra-
tion is completed.
Error recovery:
See section 5.6 (page 60) for details on specific errors.
The calibration can be exited when the instrument displays hLd1 or hLd2 by pressing the
SCROLL key.
5.4.6 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
executed 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 .
This calibration mode is only available on dual pen instruments.
Mode 2: Select Mode 2. Exit the Calibration Mode. Enter setpoint (SP) values for Pen 1 and
for Pen 2. The SP for Pen 1 is used as the dry-bulb temperature and the SP for Pen 2 is used
as the wet-bulb temperature. Enter Setpoints (dry-bulb and wet-bulb temperatures) for a
known Relative Humidity value. Pen 1 or Pen 2 must also be preselected for Relative
Humidity-PEnS=3. Check the display for the pen with PEnS=3 for the Relative Humidity
percentage based on Setpoint selections of Pen 1 and Pen 2. After viewing the Relative
Humidity percentage, enter the Calibration Mode, CAL 6, and select 0 (normal mode) for the
mode selection. Exit the Calibration Mode and return the instrument to the desired mode of
operation. This is a validation of the accuracy of the instrument’s algorithm and Pen 1 and
Pen 2 accuracy where whole numbers are used. The instrument will not control properly while
in this mode.
Note: If the Process Value exceeds 999.9, the leftmost digit will be the letter o with a bar over
it. The other digits will be valid.