IFM Electronic efector160 LI51, Operating Instructions Manual

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4
3 Functions and features
The unit monitors the level of liquids in tanks
3.1 Application area
• 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!
• For water and hydrous media with temperatures > 35° C install the unit in a
climatic tube (order no E43100 E43103)
• Maximum tank pressure: ±05 bar (when mounted using the appropriate mount-
ing 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 requested level (limit level) is reached and
indicates this by a switched signal
The dielectric constant of a medium is important for its detection Media with a
dielectric constant > 18 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