The 1-channel level controller MK91-
R11/24VDC regulates conductive liquid levels.
Electrodes connected to the device analyse
the resistance of the liquid against the container mass.
A square-wave AC voltage signal is applied
to the electrode. This enables DC-free and
therefore electrolytic-free measurement of the
liquid resistance.
The device has a relay output with a
changeover contact.

The switchpoint of the level controller is set to
Rm = 40 kò (different values on request). If the
response sensitivity falls below the set point,
the relay is energized with a delay of 10 s.
The switching status of the output is indicated
by a yellow LED and operational readiness by
a green LED.
The device provides protection against reverse polarity and transient surge protection.

■ Switching point at 40 kò
■ Hysteresis approx. 5%
■ Output: Relay with 1 changeover contact
■ Complete galvanic isolation
■ Input reverse-polarity protected