Appendix
35
WATLOW Series 945 User's Manual
T/C and RTD
Calibration
NOTE
Before calibration
on an installed
control, make sure
all data and
parameters are
documented. See
Setup, and
Operation Tables,
Pages 18 and 20.
Thermocouple Field Calibration Procedure
Equipment Required:
•
Type "J" or "R" Reference Compensator with reference junction at
32
°
F/0
°
C,
OR Type "J" or "R" Thermocouple Calibrator set at 32
°
F/0
°
C.
•
Precision millivolt source, 0-50mV min. range, 0.01mV resolution.
Setup And Calibration
1. Connect the AC line voltage L1, L2, and ground to the proper terminals.
2. Connect the millivolt source to Terminal #9 (-) and Terminal #7 (+) on the Series 945
terminal strip. Use regular 20 - 24 gauge wire.
3. Apply power to the unit and allow it to warm up for 15 minutes. After warm-up put the
unit in the CAL menu. See Page 32.
4. Press AUTO/MAN twice to enter the MANUAL mode. The unit is calibrating when the
MANUAL LED is ON. Make sure the unit is in MANUAL mode only when you are in the
correct parameters. See Figure 41. Press MODE.
5. At tcL, enter 0.00mV from the millivolt source to the control. Allow 10 seconds to
stabilize. Press MODE.
6. At tcH, enter 50.00mV for type "J" units or 16.035mV for type "R" units from the millivolt
source to the 945. Allow at least 10 seconds to stabilize. Press MODE.
7. At tc, disconnect the millivolt source, and connect the reference compensator or T/C
calibrator to Terminal #9 (-), and Terminal #7 (+) on the 945 terminal strip. Allow 10
seconds to stabilize. The unit leaves CAL if 1 minute passes between key activations.
Press AUTO/MAN twice to exit the MANUAL mode. To conclude, advance to the next
prompt or exit the CAL menu.
Table 5 -
RTD Settings.
RTD Field Calibration Procedure
Equipment Required:
•
1K
Ω
precision decade resistance box with 0.01 ohms resolution.
Setup And Calibration
1.
Connect the AC line voltage L1, L2, and ground to the proper terminals.
2.
Connect the decade resistance box to Terminal #4, 5 and 6 on the terminal strip. Use
regular 20 - 24 gauge wire of the same length and type.
3.
Apply power to the unit and allow warm up for 15 minutes. After warm-up put the unit
in the CAL menu. See Page 32. Press MODE until rLO s displayed.
4.
Press AUTO/MAN twice to enter the MANUAL mode. The unit is calibrating when the
MANUAL LED is ON. Make sure the unit is in MANUAL mode only when you are in the
correct parameters. See Figure 41.
5.
At rLO set the decade resistance box to the correct low setting below. This can be
calibrated to JIS or DIN. Allow 10 seconds to stabilize. Press MODE.
6.
At rHI, set the decade resistance box to the correct high setting. Allow at least 10
seconds to stabilize. The unit leaves the CAL mode if 1 minute passes between key
activations. Press AUTO/MAN twice to exit the MANUAL mode. To conclude,
advance the MODE key to the next prompt or exit the CAL menu.
945A-2XX0-0000
945A-3XX0-0000
Calibration
Low
High
1
°
17.31
317.33
0.1
°
59.59
177.13
IMPORTANT:
When the MANUAL
LED is ON the unit is
automatically
calibrating. Your
sequence is
VERY important.
Always move to the
next parameter
before changing the
calibration
equipment.
