Dwyer Mark - Manual (Page 15)

14
MARK 1, 3 AND 4 WITH POTENTIOMETER INSTALLATION
TERMINAL3
TERMINAL 2
TERMINAL 1
1
2
3
INSTALLATION AND ADJUSTMENT
1. Attach the switch to the actuator or valve. Refer to Installation and Adjustment Instructions:
p. 9 for Direct Drive Mark 1 and 4 Models
p. 10-11 for Lever Drive Mark 1 and 4 Models
p. 12-13 for Mark 3 Models
2. Remove cover by unscrewing. Take care to keep threads clean and free from damage.
3. On models 13XXX and 43XXX, the switches are set at the factory when in the counterclockwise position as shown.
Switch #1 is open, and #2 is closed. When cams are rotated 90º clockwise, #1 becomes closed and #2 is open.
The cams may be adjusted to increase or decrease the 90º rotation. For model 33XXX refer to pages 12 and 13
for Switch Adjustment Procedure.
4. The potentiometer is positioned at the factory with the resistance element approximately centered. The resistance
readings in the chart are typical of each different potentiometer.
5. To adjust the potentiometer to a different range, loosen the two lower set screws on the coupling. While holding the
cams in the desired position, rotate the coupling and potentiometer shaft to the preferred location. Rotating
clockwise reduces resistance between pins 2 and 1, and increases resistance between 2 and 3. Rotating
counterclockwise increases resistance between pins 2 and 1, and reduces resistance between 2 and 3. If the
resistance “jumps” rapidly, the pot is improperly rotated and functioning in the 20º dead area. Retighten the 2 set
screws. A 2K span adjustment pot is provided, to activate move bypass shunt to the other pin.
See Pages 19-25 for wiring procedure, intrinsic safety parameters, relevant warnings and schematics.
Potentiometer
Resistance
Ohms
1000
2000
5000
10000
20000
Ohms Per Degree
of Rotation
2.9
5.8
14.7
29.4
58.8
Resistance Between Pins
No. 2 to No. 1 No. 2 to No. 3
CCW-SET
500
1000
2500
5000
10000 CW-90°
235
471
1178
2354
4708 CCW-SET
500
1000
2500
5000
10000 CW-90°
765
1529
3823
7646
15294