Instructions Manual

Pub. #OM17-MSP3
6-41
2. Adjust prox sensor gap if needed. Adjust sensor to 1/4”- 3/8” (6-9 mm) gap (Figure 15.3).
Cycle unit manually to insure that this gap is maintained throughout cycling range.
Figure15.3 Prox sensor gap
3. Adjust prox sensor height if needed. Loosen bolt holding prox sensor arm and rotate to
change height of prox sensor (Figure 15.4). Adjust prox sensor height with sampler shoe
completely raised. Adjust the prox sensor so it barely clears the lower part of the sensor
plate when sampler is completely raised. It may be necessary to reposition the electrode
holder and/or sampler shoe after adjusting prox sensor. If sampler shoe is unable to
penetrate hard soil, the prox sensor may not be able to clear the top of the plate. If that
happens, the sampler will appear to have locked in the down position—when in reality it just
isn’t able to clear the metal plate. In that case, the external controller has not received the
message from the prox sensor to move to the next step in the sequence—raising the shoe
for pH measurement.
Figure 15.4 Pivot bolt for adjusting prox sensor arm
1/4 to 3/8” gap
(6-9 mm)