User`s manual

WATLOW Series 965 User's Manual
33
Appendix
4-20mA Output Field Calibration Procedure
Equipment Required:
• 300Ω, 1/2 watt 10% resistor.
• 4 - 1/2 digit Digital Multimeter.
Setup And Calibration
1. Connect the ac line voltage L1 and L2 to the proper terminals of the 965. See
Chapter 2. Set the multimeter to measure current.
2. Connect the multimeter in series with the 300Ω resistor to Terminal 9 Positive and 10
Negative on the Series 965 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. Press the MODE key until the 4A0 prompt is displayed.
4. Press the A/M key twice to enter the MANUAL mode. The unit is calibrating when the
MANUAL LED is on.
5. At the 4A0 prompt, the multimeter should read approximately 4mA. Allow at least 10
seconds to stabilize.
6. Use the
Up-arrow/Down-arrow keys (reverse acting) to adjust the reading on the
multimeter for 3.85mA ± 0.10mA. Press the MODE key.
7. At the 2A0 prompt, the multimeter should read approximately 20mA. Allow at least
10 seconds to stabilize. The unit will leave the CAL mode if 1 minute passes
between key activations except for 4-20mA units.
8. Use the UP/DOWN keys (reverse acting) to adjust the reading on the multimeter for
20.15mA ±0.10mA.
9. To conclude the 4-20mA output calibration, advance the MODE key to the next
prompt or exit the CAL menu.
NOTE:
Before calibration
on an installed
control, make sure
all data and
parameters are
documented. See
Setup and Operation
Charts, Pages 18
and 20.
4-20mA Output
NOTE:
When the MN LED is
on, the unit is
automatically
calibrating. Your
sequence is VERY
important. Always
move to the next
parameter before
changing the
calibration equip-
ment.