Function And Features; Functional Overview - IFM Electronic efector 160 LK81 Series Operating Instructions Manual

Function and features

Applications
The level sensor LK81 was specially designed to meet the require-
ments of machine tool building. It is specially suitable for monitoring
coolant emulsions (also dirty) as well as cutting and hydraulic oils.
Restriction of the application area
• The sensor is not suitable for extremely conductive and adhering
media, granulates and bulk materials, acids and alkalis. It is not suit-
able for food and electroplating applications.
• The sensor is not suitable for use in grinders.
• It is possible that foam of good conductivity is detected as level.
Check the effects in your application.
• For water and hydrous media with temperatures > 35°C the unit
must be mounted into a climatic tube (order no. E43100, E43101,
E43102).

Functional overview

Measuring principle
The sensor determines the level of fluids according to the capacitive
measuring principle:
• An electrical field is generated and influenced by the medium to be
detected. This change to the field causes a measurement signal that
is electronically evaluated.
• The dielectric constant of a medium is important for its detection.
Media with a high dielectric constant (e.g. water) generate a strong
measurement signal, media with a low dielectric constant (e.g. oils)
a correspondingly lower signal.
• The active measurement zone of the sensor probe is composed of
16 capacitive measuring segments. They generate measurement
signals depending on the degree of coverage.
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