Duff-Norton SK6415-300 (SPA Series DC) - Manual (Page 6)

ii. Being careful not to turn the pot shaft, slide
it into engagement with the plastic worm and
tighten locknut.
iii. Re-check resistance. If necessary loosen
locknut slightly and twist pot to re-establish
100 ohm resistance. Pot does not have end
of travel stops, but has a 20˚ deadband
between the two ends of the resistive element.
No continuity will be measured to terminal S
if the slider is in the deadband.
iv. Run actuator to full extension (do not let
tube rotate) until it is stopped by its limit
switch.
v. Check resistance between S and CCW to
be sure the slider is still on the element and
the resistance is greater than 100 ohms. The
pot has enough rotation for 9.43 inches of
travel. (For strokes shorter than 9”, the
retracted resistance can be increased so that
pot adjustment is less critical.
b. For travels greater than 9”
(multi-turn pot):
i. Turn pot shaft counterclockwise until it
reaches its stop. Now turn shaft back
clockwise
1 / 4 turn.
ii. Without turning pot shaft, slide pot onto
engagement with the plastic worm and tighten
locknut.
iii. Starting 1 /
4
turn from the end, the 3-turn
pot has enough rotation for 25” of actuator
travel.
6. With this set-up, potentiometer will have increasing
resistance from S to CCW (and decreasing resistance
from S to CW) as the actuator extends.
2-5. Digital Position Indicator (Duff-
Norton part no. SK6300-4K)
The model SK6300-4K is a highly versatile, panel
mount, digital readout device that provides a very precise
indication of actuator position. It can be programmed to
display percentage, inches, or any other desired unit.
The indicator is self calibrating with no need for
measurements or calculations.
See detailed instructions with the SK6300-4K
indicator for installation and programming instructions.
Potentiometer terminal CCW should be connected to
indicator Common, CW to Excitation Voltage, and S to
Signal Voltage Input.
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