Flowserve Modutronic 20 II Modulating Position Controlle - Manual (Page 21)

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Limitorque Actuation Systems Modutronic 20 II FCD LMENIM4002-00 – 08/06
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a. Set the mA Calibrator to the maximum command signal (normally 20 mA).
b. The unit may:
1. Run toward the maximum position and stop short of the Position Limit Switch trip point,
or
2. Remain in position.
c. Rotate the SPAN Potentiometer slowly CW z . This will cause the Actuator to move slowly
toward the maximum (normally OPEN) position. Continue rotating the SPAN control CW z
until the maximum (OPEN) Position Limit Switch trips and the motor stops. The OPEN LED
should illuminate each time the Motor operates.
11. After initially setting the ZERO and SPAN setting, use the mA Calibrator to set the Command
Signal back to the minimum setting (usually 4 mA); allow the actuator to run until it stops. Now
fine-tune the ZERO setting for the position where the Limit Switch just trips.
12. Use the mA Calibrator to set the Command Signal back to the maximum setting (usually 20 mA);
allow the actuator to run until it stops. Now fine-tune the SPAN setting for the position where the
Limit Switch just trips.
NOTE: If hunting continues during calibration procedure, it may be necessary to temporarily
decrease the GAIN setting or increase the DEADBAND setting to get the ZERO and SPAN settings
calibrated.
13. Adjust the ON TIME (optional). This step adjusts the period of time the Motor is energized in the
pulsing mode when it is approaching the final set-point position.
NOTE: The ON TIME must be adjusted prior to adjusting the OFF TIME. Adjusting the ON TIME
after adjusting the OFF TIME will require repeating the OFF TIME adjustment.
The duration of the ON TIME pulse to the Contactor/Solid State Reverser is increased by rotating
the ON TIME Potentiometer CW
z .
14. Adjust the OFF TIME (optional). This step adjusts the period of time the Motor is de-energized in
the pulsing mode when it is approaching the final set-point position. This can also be described
as the interval between ON TIME pulses. The duration of the OFF TIME pulse to the Contactor/
Solid State Reverser is increased by rotating the OFF TIME Potentiometer CW
z .
15. Adjust the GAIN. This step calibrates the width of the pulsing window around the set-point.
This control works in conjunction with the four DIP Switches located on the Mod 20 II circuit
board to determine the final accuracy of the unit in regard to set point position. The wider the
pulsing window, the greater the distance from the set-point the unit enters the pulsing mode.
It is desirable to minimize the pulsing window without causing the Actuator to hunt (oscillate
uncontrollably around the set-point).
a. For the initial calibration, ensure that DIP Switch 3 is ON and Dip Switches 1, 2, and 4 are
OFF. This will provide 1% DEADBAND.
NOTE: If no DIP Switch is set to the ON position, the actuator will not operate.
b. Make sure the GAIN Potentiometer is at the midpoint, then rotate the GAIN Potentiometer
one turn CW z .
c. Start with the mA Calibrator at 4 mA, then make a 5 mA change in the output of the mA
Calibrator to provide a significant change of position; now watch the action of the actuator.