3.2 Principle of operation
The device functions in accordance with the conductivity principle (conductive fill
level measurement). The device issues a low alternating voltage to the sensors:
■ In the case of level rod probes, the electric circuit is closed by means of
the conductive liquid.
■ In the case of float switches, the electric circuit is closed by means of
magnetically actuated reed switches.
The LEDs on the device indicate whether or not the electric circuit is closed.
Whether or not the sensor signal is detected depends on the response sensitivity.
The active status of each relay can be set using the sliders. The sliders can be
used to invert the switching signal without having to change the cabling.
Minimum/maximum control using the ENR 300 level controller
When the highest or lowest fill level is reached, the relays switch over.