4
3 Functions and features
The unit monitors the level of liquids in tanks�
3.1 Applications
● Water, hydrous media, oils, coolant emulsions�
3.2 Restriction of the application area
● The unit is not suitable for acids, alkalis, granulates, bulk materials�
● It is not suitable for hygienic areas�
● Highly conductive foam can trigger a switching operation� Check the conse-
quences by performing a test in your application!
● Maximum tank pressure: ± 0�5 bar (when mounted using the appropriate
mounting accessories; → chapter 5�2 Installation procedure)�
4 Function
4.1 Measuring principle
The unit operates to the capacitive measuring principle� By direct contact with the
medium the unit detects whether the maximum level (limit level) is reached and
indicates this by a switched signal�
Max� level reached
output open (OFF)
Max� level not reached
output closed (ON)
The dielectric constant of a medium is important for its detection� Media with a
dielectric constant > 1�8 are safely detected�
Dielectric constants of common liquids
Mineral oil
≈ 2
Coolant emulsion
≈ 25���75
Glycol
≈ 37
Water
≈ 80
Water, demineralised
≈ 30
Electrically conductive and non conductive media are detected�
