Flowserve I90 Series Intrinsically Safe Modular Accessory System - Manual (Page 13)

making the potentiometer adjustment. In the case of a double-
acting actuator, either temporarily connect air to the
appropriate actuator port or use a wrench to move the
actuator to the closed position. Unless there is air supplied to
a spring-return actuator, it should automatically be in the
closed position. Using an ohmmeter, measure the resistance
between the purple and the white/black potentiometer leads at
the terminal strip. Rotate the face gear to obtain a resistance
on the ohmmeter of 80 to 90 ohms.
NOTE: It is not necessary to loosen or remove face gear snap
ring to rotate gear.
IMPORTANT: The feedback potentiometer is calibrated for only
one 90 degree quadrant of valve operation. If the output shaft
is repositioned to another 90 degree quadrant, or if the output
shaft is rotated a multiple of 360 degrees from its original
position, or if the M.A.S. package is removed from the
actuator, the feedback potentiometer will no longer be in
calibration and must be recalibrated as directed.
4. TROUBLESHOOTING
See table below.
Flow Control Division
Worcester Controls
WCAIM2033 Intrinsically Safe Modular Accessory System (Series I90) 13
PROBLEM POSSIBLE CAUSE(S) SOLUTION
Indicates backwards Green and Purple wires reversed Check wiring per Section III.D.2.
Reverse-acting actuator Reverse green and purple wires. Recalibrate
potentiometer per Section III.D.3.
Indication not consistent Gears slipping Check gear tooth engagement (approximately Z\zn").
Pinion gear set screw loose Recalibrate and tighten set screw.
Indication not correct Potentiometer needs to be calibrated. Calibrate pot. per Section III.D.3.
M.A.S. shaft turned more than 90 degrees Re-calibrate for new quadrant.
Figure 21
“P” Single-feedback potentiometer
NOTE: FOR INTRINSICALLY SAFE SYSTEMS ONLY. All inputs/outputs
(“external” wiring connections) must be run through approved
intrinsic safety barriers.
IMPORTANT: Shielded cable must be used for each intrinsically safe
circuit and the shield must be connected to Zener barrier ground.