Flowserve AF-17 Electronic Positioner - Manual (Page 17)

WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 17
3.6.3 AF-17-5V, AF-17-XV (Direct Voltage Input Signal for AF-17)
For a voltage input signal, the more positive or “High” signal lead should connect to terminal 11. The less positive or
“Common” lead should connect to terminal 10. Terminal 10 is (-), Terminal 11 is (+).
This positioner is available for use with the standard direct voltage signals: 0 to 5 VDC and 0 to 10 VDC. The positioner
board is factory calibrated for one of these two signal ranges and field changes are not advised.
Paragraph 6.4.1 gives the nominal resistance load that the positioner presents to the control circuit for the two
signal ranges.
4.0 CALIBRATION AND ADJUSTMENT
4.1 Initial Set-Up and Adjustment (Applies To All Models)
When properly adjusted, the actuator will stop at the full open and full closed points as a result of having reached one of the limits
of the input signal span, and the actuator’s limit switches will be used in a back-up mode to stop the actuator, should an out-of-
range input signal occur.
In case of Series 75, 240 VAC Actuator with AF-17 240 VAC positioner, the two limit switches do not limit actuator travel. Exercise
caution not to override limit switches. Reference paragraph 3.4.4.
Actuators with factory-mounted positioners will be shipped with their limit switches properly adjusted. When the positioner,
whether internally or externally mounted, is installed to an actuator in the field, the actuator limit switches should be initially
adjusted to trip at 1 to 3 degrees AFTER the positioner would normally have shut the actuator off upon reaching the upper or
lower input signal limit. Reference parts 4.2, 4.3 and paragraph 4.7.1. CAUTION: If either the valve or the actuator have mechanical
end of travel stops, the limit switches should be set to trip JUST before a mechanical stop is reached even if this point is
coincident with one of the limits of the input signal.
NOTE: Prior to starting potentiometer adjustment procedure set the AF-17 adjustment potentiometers as follows: “Range”
and “Zero” potentiometers full clockwise, “AH” full clockwise then
1 /
4
turn counter-clockwise.
4.2 “Zero” Adjustment [“Zero” Potentiometer Initially Full Clockwise (CW)]
Apply a “full closed” signal to the positioners input, i.e., 4 mA. The actuator should rotate in the CW direction and come to a stop
at or near the CW limit of rotation. Adjust the “Zero” adjustment until the actuator stops in the fully closed position AND the
indicator LD2 is “OFF”. If LD2 is “ON”, this indicates that the “Closed” (SW-1) limit switch has tripped. The “Closed” limit switch
should be adjusted such that it will trip 1° to 3° beyond the full closed position of the actuator. Readjust the “Closed” limit switch
if necessary.
4.3 “Range” Adjustment [“Range” Potentiometer Initially Full Clockwise (CW)]
Apply a “full open” signal to the positioners input, i.e., 20 mA. The actuator should rotate in the CCW direction and come to a stop
at or near the CCW limit of rotation. Adjust the “Range” adjustment until the actuator stops in the fully open position AND the
indicator LD1 is “OFF”. If LD1 is “ON”, this indicates that the “Open” (SW-2) limit switch has tripped. The “Open” limit switch
should be adjusted such that it will trip 1° to 3° beyond the full “Open” position of the actuator. Readjust the “Open” limit switch if
necessary. When 4.2 and 4.3 are complete, ensure that limit switches are set 1° to 3° beyond the electronic travel limits.
Reference CAUTION in 4.1.
4.4 “AH” Adjustment (Anti-Hunt) (“AH” Potentiometer – turn fully clockwise (CW),
then 1 /
4
turn CCW)
This adjustment can be made only after installation is complete and actuator is operational. Apply sufficient input signal to turn the
actuator shaft an amount that would open the valve approximately 10%. If the actuator hunts, adjust the “AH” control in a CCW
direction until the hunting stops. If no hunting occurs, adjust the control towards the CW direction. Increase the input signal in
steps of approximately 10% and reset the “AH” adjustment until no hunting occurs over the entire input signal range.
Flow Control Division
Worcester Controls