Adjustment Of The Switching Points Kfa - Rechner Sensors LEVEL KFS-4 Série Manuel D'utilisation

Adjustment of the switching points KFA-4...

KFA-4 Switching unit with adjustable limit value
Principle of operation
The KFS-5 rod probes have as standard measuring electrodes that are small in size (height). For that reason,
the limit switching point only can vary within this range, dependent on the dielectric constant (DC) of the
material to be detected and the adjustment.
The high repeatability of the three-electrode measuring principle allows for a further exceptional application:
to assign a limit value with small hysteresis to a rod probe with a measuring electrode of large dimension,
designated as variable measuring electrode. By means of the adjustment the limit value can be assigned at
any position within the variable range.
The KFA-4-...evaluation units and the corresponding probes KFS-4-... are tuned to each other. With pairing
of non matching units the function can not be guaranteed.
Adjustment of KFA-4-... units
The basic principle for the adjustment is the same as for KFA-5-... limit value measurements, see page 23.
In the first place, the adjustment when empty can be made in the same way as for the KFA-5-... With this
the switching point is at the lowest position of the variable range. For the adjustment of another switching
point within the variable range it is necessary that the level to be detected is visible.
Adjustment of a variable switching point with eye contact of the filling level:
Fill the container up to the desired height and then make the empty adjustment. (see page 23).
Adjustment of the variable switching point with no eye contact of the filling level
- with free measuring electrode – that means with an empty container –make the empty adjustment (see
page 23).
- after that the container should be filled to cover the entire measuring range and with this state make the full
adjustment (see page 23). At the same time the turns of the adjustment potentiometer should be counted. The
increase of the filling level and the turn's of the adjustment potentiometer are linear to each other, therefore
any position within the variable range can be adjusted by interpolation.
Warning:
The variable limit values are dependent on the dielectric constant values of the products. For products with
wide varying characteristics the KFA-4... measurement is not recommended (Then please use KFA-5...!)
Dimensions
Dimension No. 5
26