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WATLOW Series 942 User's Manual
Appendix
0-5 or 0-10 Volt Output Field Calibration Procedure
Before attempting any calibration procedure, make sure you have the
proper equipment called for in each procedure.
Equipment Required
•
20K
Ω
, 1/4 watt, 10% resistor
•
4 1/2 digit Digital Multimeter.
Setup and Calibration
1. Connect the AC line voltage L1, L2, and ground to the proper terminals of
the 942. See Chapter 2.
2. Connect the multimeter across the 20K
Ω
resistor to Terminal #17 (+) and
#18 (-)for 0-5Volt units on the Series 942 terminal strip. Use Terminal #17
(+) and #16 (-) for 0-10Volt units. 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 54. Press the MODE
key until the
O1LO
parameter is displayed.
IMPORTANT:
When the RUN LED is ON the unit is automatically calibrating. Your
sequence is VERY important. Always move to the next parameter before
changing the calibration equipment. When you have completed all of the 0 - 5
Volt output calibration parameters, press the HOLD/RUN key twice. Failure to do
so will result in inaccurate calibration values.
4. Press the HOLD/RUN key twice to enter the RUN mode. The unit is
calibrating when the RUN LED is ON. Make sure the unit is in the RUN
mode
only
when you are in the correct parameters. See Page 55.
5. At the
O1LO
parameter, the multimeter should read approximately 0.000V.
Allow at least 10 seconds to stabilize.
6. Use the UP/DOWN keys (reverse acting) to adjust the reading on the
multimeter for -0.2V
±
0.1V on 0-5Volt units and 0.0V
±
0.1V for 0-10Volt
units. Press the MODE key.
7. At the
O1HI
parameter, the multimeter should read approximately 5.000V.
Allow at least 10 seconds to stabilize. The unit will leave the CAL mode if 1
minute passes between key activations.
8. Use the UP/DOWN keys (reverse acting) to adjust the reading on the
multimeter for 5.2V
±
0.1V for 0-5Volt units and 5.0V
±
0.1V for 0-10Volt
units.
9. Press the HOLD/RUN key twice to exit the RUN mode. To conclude the
output calibration, advance the MODE key to the next parameter or exit the
Calibration menu by pressing the HOLD/RUN key twice.
NOTE
Before calibration
on an installed
control, make sure
all data and para-
meters are docu-
mented. See the
Setup and Operation
Tables, and the
Master Step Chart,
Pages 27, 30 and 35.
0-5/0-10 Volt Output
