Appendix
38
WATLOW Series 945 User's Manual
0-5V/4-20mA Retransmit
IMPORTANT:
When the MANUAL
LED is ON the unit is
automatically
calibrating. Your
sequence is
VERY important.
Always move to the
next prompt before
changing the
calibration
equipment.
NOTE:
Before calibration on
an installed control,
make sure all data
and parameters are
documented. See
Setup and Operation
Tables, Pages 18
and 20.
0 - 5 Volt Retransmit Field Calibration 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 945.
2.
Connect the multimeter across the 20K
Ω
resistor to Terminal #25 Positive and #24
Negative 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. Press MODE until the O4LO prompt is displayed.
4.
Press the AUTO/MAN key twice to enter the MANUAL mode. The unit is calibrating
when the MANUAL LED is ON. Make sure the unit is in the MANUAL mode only when
you are in the correct parameters. See Figure 41.
5.
At the O4LO parameter, the multimeter should read approximately 0.00V. Allow at least
10 seconds to stabilize.
6.
Use the UP/DOWN keys (reverse acting) to adjust the reading on the multimeter for 0.0
volts. Press the MODE key.
7.
At O4HI, the multimeter should read approximately 5.00V. Allow at least 10 seconds to
stabilize. The unit leaves the CAL mode if 1 minute passes between key activations.
8.
Use the AUTO/MAN key twice to exit the MANUAL mode. To conclude the 0-5 volt
output calibration, advance the MODE key to the next prompt or exit the CAL menu.
4-20mA Retransmit Field Calibration Procedure
Equipment Required:
•
470
Ω
, 1/2 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 945.
2.
Connect the multimeter in series with the 470
Ω
resistor to Terminal #25 Positive and
#24 Negative 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. Press MODE until the O4LO prompt is displayed.
4.
Press the AUTO/MAN key twice to enter the MANUAL mode. The unit is calibrating
when the MANUAL LED is ON. Make sure the unit is in the MANUAL mode only when
you are in the correct parameters. See Figure 41.
5.
At the O4LO parameter, the multimeter should read approximately 4mA. Allow at least
10 seconds to stabilize.
6.
Use the UP/DOWN keys (reverse acting) to adjust the reading on the multimeter for
4.00mA. Press the MODE key.
7.
At O4HI, the multimeter should read approximately 20mA. Allow at least 10 seconds to
stabilize. The unit leaves 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
20.00mA.
9.
Press AUTO/MAN twice to exit the MANUAL mode. To conclude, advance the MODE
key to the next prompt or exit the CAL menu.
