Flowserve APEX 8000 High-Performance Positioner - Manual (Page 7)

6. Set input signal to mid scale (9 psi for 3-15 psi span). Output pressure level cannot be adjusted with actuator against valve seat or travel
stops. Allow actuator pressure to stabilize.
7. Observe the pressure gauges. If reading is not correct, turn balance adjustment screw about 1/8 turn at a time and wait about 20-30
seconds for pressure to stabilize (counter clockwise to increase pressure). Continue until output pressure level of the higher pressure
gauge is approxi mately 80 percent of supply.
8. Replace rubber cap over balance adjustment screw.
Figure 5: Close-up of Gain Adjustment Figure 6: Gain Adjustment
Gain Adjustment Procedure
The unique gain adjustment on the APEX 8000 positioner provides a means to increase or decrease the responsiveness of the valve/actuator/
positioner system. Increasing gain makes the valve more responsive and faster, while decreasing gain makes the system less sensitive and
slower to respond (with increased damping).
1. Before adjusting the gain, place controller on manual and isolate the valve from the process.
2. Turn off supply air to control valve actuator.
3. Using a 5/64-inch allen wrench, loosen both upper and lower lock screws about one half turn. Do not loosen the spacer nut. (See Figure
6)
4. By grasping adjust lever, carefully rotate gain adjust assem bly to desired position. Make sure both upper and lower gain adjust plates
rotate together. When they are rotated to the new position, the connecting spring should be perpendicular to the plates.
Caution: To avoid damaging gain adjust connecting spring mechanism, make sure both upper and lower gain adjust plates rotate
together. When they are rotated to the new position, the connecting spring should be perpendicular to the plates.
5. When the gain is set to the desired position, firmly tighten both lock screws.
6. Turn on the supply pressure. Check actuator responsive ness by providing a step signal to positioner. When gain is set as desired, check
valve zero and span calibration and re-calibrate if needed.
7. Return the valve to service.
Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
7
Upper
Lock Screw
Lower
Lock Screw
Adjust Lever
Spacer Nut
(Do not loosen)