Conductive build-up at the
probe
A bridge must inserted between terminals 1 and 2 of the electronic
insert if there is a tendency to conductive build-up at the probe:
•
Choose a probe which is almost fully insulated
•
Calibrate and operate with terminals 1 and 2 of the electronic
insert shorted by a bridge.
•
Check the switching point at regular intervals.
If necessary, check and free the probes of build-up. Table 2
indicates the likelyhood of build-up of the probe.
Replacement of the Nivotester
Should it prove necessary to replace the Nivotester, the
substitution can be made without the need to rewire.
Step Procedure
1
Release the terminal blocks by inserting a screwdriver
blade into the release point, see Fig.3, and prising them
apart.
2
Release the snap-on fastening by inserting a screwdriver
blade in the release point and prising downwards.
3
Remove the old unit, snap the new unit onto the mounting
rail.
4
Press home the terminal blocks, 6-pole below, 7-pole
above the front panel.
5
Calibrate the unit as described in Chapter 3.
Procedure:
Exchanging the Nivotester
Product
Conductivity
Tendency to
build-up
Bridge at
Terminals 1-2
Dry bulk solids
Low
Low
no
Moist bulk solids
Medium
Medium
no
Water-containing
liquids
High
Depends on
dilution - the
thicker the
more likely
dilute: no
pasty, sticky:
yes
Sludge
High
Very high
yes
Table 2
Tendency of different materials to
form conductive build-up on the
probe
Installation
29
