Flowserve SMB Series Electric Actuators - Manual (Page 28)

SMB Series/SB Series Installation and Maintenance FCD LMENIM1401-04-AQ – 01/15
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8. Adjust the OPEN position setting to a value at or below 1000 ohms for the 1000-ohm potentiom-
eter; at or below 50 ohms for the 50-ohm potentiometer.
9. Repeat steps 5 through 8 and fine-tune as necessary.
4.6.3 Remote Position Indicator
(Resistance-to-Current Signal Converter)
The SMB or SB actuator with a signal converter installed transmits a 4-20 mA output signal to a
remote position indicator (meter). The signal converter responds to the input of a 1000-ohm
potentiometer and can be powered by 24 VDC or 120 VAC for the older version R/I converter; or
18 VDC, 24 VDC, or 120 VDC for the PT20SD style R/I converter.
To set the R/I signal converter:
NOTE: The pinion has been disengaged to prevent damaging the potentiometer prior to setting the
valve.
1. Set the potentiometer by turning the pinion until the desired reading is obtained.
2. Loosen the hex nut on the back of the potentiometer and slide the potentiometer in the direction
of the idler pinion until the pinions are engaged.
3. Do not force the engagement of the pinions.
4. Retighten the hex nut on the back of the potentiometer.
5. Do not engage the pinion until the actuator and valve positions have been set.
To calibrate the R/I signal converter:
1. Position the valve at 50% of full travel.
2. Read the ohms from the wiper to either end of the potentiometer.
3. To set the potentiometer to the proper value, loosen the set screw on the potentiometer shaft
pinion and rotate the potentiometer shaft to a reading of 500 ohms.
4. Tighten the set screw.
5. Run the actuator to the fully CLOSED position.
6. Adjust the ZERO control to an output of 4 mA.
7. Run the actuator to the fully OPEN position.
8. Adjust the SPAN control to an output of 20 mA.
9. Repeat steps 5 through 8 to fine-tune as necessary.