Veris Technologies Quad 1000 Soil EC Mapping System - Operating Instructions - Manual (Page 29)

OM17-Quad1000
6-8
C. Testing Disk-Electrode isolation
If continuity tests show no excessive resistance on any channel, yet erratic soil EC readings
continue, or if EC readings do not drop to
–1 when unit is out of the soil, it is possible that the
channels are not isolated. This could be the result of a pinched wiring cable, causing channels to
short out. Or, one of the disk-electrodes is no longer insulated properly from the frame or adjacent
disk-electrodes.
1. If EC readings do not drop to –1 when unit is raised, disconnect signal cable extension from
im
plement. If readings don’t drop to –1, the problem is with the signal cable extension. If
readings show -1, re-insert the signal cable extension into the implement. Disconnect the
connector wire from each disk electrode. If readings don’t drop to –1, the problem is with the
wiring harness. If this is the case, you should replace the wiring harness. If readings do
drop, re-insert the signal cable extension into the implement. The problem is with one or
more of the disk-electrodes. Proceed as follows:
2. Inspect nylon insulation slides under disk-electrode mounting brackets. These nylon
insulators may become worn or brittle, or may slip out from under mounting bracket. Repair
and replace as necessary. Make sure that all electrode disk U-bolts are properly tightened
to clamp mounting bracket and insulation tightly to frame.
Figure 3.7
3. Check so see that no metal part of the any disk electrode is in contact with the implement
frame. This may be by visual inspection or by connecting one lead of an ohmmeter to the
individual disk electrode or wire connector bolt , and the other to a grounded fastener on the
frame (Figure 3.8). If the disk electrode is properly isolated, no reading will be obtained.
Make sure that all electrode disk clamp bolts are properly tightened to prevent lateral
movement of the disk electrode.
nylon
insulation