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WATLOW Series 988 Calibration Manual
VDC Process Input Procedure
0 to 5VDC and 0 to 10VDC units
Equipment Required
• Precision Voltage source 0-10 volt minimum range with .001 volt resolution.
Setup and Calibration
1. Connect the AC voltage L1, L2 and ground to the proper terminals on the
Series 988. See chapter 2 in the user’s manual.
2. For Input #1 calibration: Connect the voltage source to terminal #9 (+)
terminal #10 (-) on the 988 terminal strip. Use 20 to 24 gauge copper wire.
Remove the control from the case and set the Input 1 DIP switches to:
1 ON
2 ON
3 ON
For Input #2 calibration: Connect the voltage source to terminal #19 (+) and
#20 (-) on the 988 terminal strip. Use 20 to 24 gauge copper wire. Remove the
control from the case and set the Input 2 DIP switches to:
1 ON
2 ON
3 ON
3. Apply power to the unit and let it warm up for 15 minutes. After warm up put
the unit in the CAL menu. See Page 6.
When performing calibration procedures, always do the Input 1 prompts
(beginning with an “A”) first, then continue on to the Input 2 prompts
(beginning with a “B”). See the Calibration menu on Page 6.
4. At the A10U or B10U prompt, enter 10.000 volts from the voltage source to the
Series 988. Allow at least 10 seconds to stabilize. Press the Up key to change
the upper display to YES. Press the Mode key .
5. At the A 0U or B 0U prompt, enter 0.000 volts from the voltage source to the
Series 988. Allow at least 10 seconds to stabilize. Press the Up key to change
the upper display to YES. Press the Mode key . To conclude the voltage
process calibration press the Display key.
VDC Process Input
NOTE:
Any prompt begin-
ning with an “A”
applies to Input 1.
Those beginning
with a “B” apply to
Input 2.
