Veris Technologies pH Manager - Operating Instructions - Manual (Page 62)

Pub.# OM17-MSP-pH
6-17
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.
Figure 4.1.
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.
.
Figures 4.2a and b. Prox sensor and LED light
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