Veris Technologies MSP EC and pH (1997-2008 floppy disk drive 1.02E) - Operating Instructions - Manual (Page 61)

Veris Technologies
Pub. #OM MSP03-1
61
Procedure #4: Trouble-shooting Prox Sensor
The prox sensor, located on the left of the sampler shoe parallel linkage arm, is critical to the
machine’s function. It informs the external controller of the sampler’s position, which allows the
controller to move the sampler to the next position in the sampling/measuring sequence. If the prox
sensor is not functioning properly, the entire operation will be affected. The problem may be with the
Prox sensor itself or with its adjustment. Follow flow chart below to address problems in their logical
sequence.
1. Inspect LED light on prox sensor. Red LED light should light whenever prox sensor is
near metal and not light when away from metal (Figure 1). This sequence indicates to the
external controller the status of the shoe: whether the shoe is down and needs to come up for
pH measuring, or it’s up and needs to go down for the next sample, etc. To view LED light,
shade ambient light from prox sensor and cycle sampler assembly manually. Be careful to
not strike or damage prox sensor face. KEEP HANDS CLEAR OF CYCLING MECHANISM.
.
Figure 1. Prox sensor and LED light
2. Adjust prox sensor gap if needed. Adjust sensor to 1/4”- 3/8” (6-9 mm) gap (Figure 2).
Cycle unit manually to insure that this gap is maintained throughout cycling range.
Prox Sensor light
Light is off when
sensor is above and
below plate, and over
center gap; Light is on
as metal passes by
sensor