Flowserve XL Series High-Performance Positioner - Manual (Page 6)

45-6 Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
Grounding Screw
Zero
Adjustment
Span
Adjustment
Minimum Pressure
Cutoff Adjustment
Spacer Nut
(Do not
loosen)
Gain Adjustment Procedure
The unique gain adjustment on the XL positioner pro-
vides a means to increase or decrease the responsive-
ness of the valve / actuator / positioner system. Increas-
ing the gain makes the valve more responsive and faster,
while decreasing the gain makes the system less sen-
sitive and slower to respond (with increased damping).
The gain is infinitely adjustable between its highest and
lowest settings. For convenience, three marks indicate
high (H), medium (M) and low (L) gain. Most sizes of
actuators will respond well to a medium (M) gain set-
ting. All XL positioners are factory-set on the medium
(M) gain setting. Unique actuator / valve configurations
may require a gain adjustment at the factory or in the
field.
1. Before adjusting the gain, place the controller on
manual and isolate the valve from the process.
2. Turn off the supply air to the control valve actuator.
3. Using a 5 /
64
-inch Allen wrench, loosen both the
upper and lower lock screws about one half turn.
Do not loosen the spacer nut. (See Figure 9.)
4. By grasping the adjust lever, carefully rotate the
gain adjust assembly to the desired position.
CAUTION: To avoid damaging the gain adjust
connecting spring mechanism. Make sure both
the upper and lower gain adjust plates rotate
together. When they are rotated to the new
position, the connecting spring should be per-
pendicular to the plates.
5. When the gain is set to the desired position, firmly
tighten both lock-down screws.
6. Turn on the supply pressure. Check the actuator
responsiveness by providing a step signal to the
positioner. When the gain is set as desired, check
the valve zero and span calibration and re-calibrate
if needed.
7. Return the valve to service.
Calibrating I/P Module Zero and Span
Settings
NOTE: Although calibration can be accomplished
using the output pressure gauge on the I/P module,
its accuracy is
±
3 percent. The standard gauge
should be removed only for calibration and more
accurate calibration equipment of
±
0.1 percent of
span should be used. The pressure gauge port is
1 /
8
-inch NPT. Calibration manifolds are available
from the factory (Part No. 97370).
Figure 9: Gain Adjustment
Figure 8: Close-up of Gain Adjustment
Figure 10: NT 3000 Module Circuit Board
(housing cover removed)
Upper
Lock Screw
Lower
Lock Screw
Adjust Lever
Circuit Board
Mounting Screws
Current Loop
Termination (-)
Current Loop
Termination (+)
Terminal Block