Admittance Type Level Switch (Model – LSY)

RF Admittance is a static level sensor with no moving parts. Its sensing parts are:- Earth Extension.


  • Compact size.
  • Universal industrial power supply (15 to 80 VDC & 15 to 260 VAC).
  • Low power consumption.
  • Easy calibration.
  • Active shield compensation against material build-up.
  • Static charge safe for fly-ash, acids, plastic & other applications susceptible to static charge/electricity.
  • Customized process connection like Threaded/Flanged etc.
  • Remote electronics version available on request.
  • Exd version available-suitable for gas group IIC, T6 as per IEC 60079-1-2007 & IEC 600529-2001.


trumenRF Admittance is a static level sensor with no moving parts. Its sensing parts are:-
1) Earth Extension (body)
2) Compensation Shield
3) Sensing Rod

trumen…which form three capacitances:-
1) Shield Earth Capacitance
2) Shield Sense Capacitance
3) Sense Earth Capacitance

trumenA Sine wave of high frequency is fed into both Sensing Rod as well as Compensation Shield. Voltage at shield is equal to voltage at sense, no effective current flows between sense and shield.

trumenThis same voltage or equi-potential drive to sense and shield removes shield-sense capacitance from the
measurement. Shield-earth capacitance is ignored by circuit.
This removes the effect of material coating on probe.

trumenWhich makes the probe selectively sensitive and by virtue of electrostatic loading of shield, it actually makes admittance device reverse sensitive in the shield-earth region.

trumenSince, level is detected by measuring sense-earth capacitance only, level is not sensed until sufficient amount of material covers sense & earth combined.



  • Suitable for all sticky/non-sticky bulk solids & liquids.
  • Suitable for side as well as top mounting.
  • Process temperature max 600 ºC (ceramic insulation).
  • Process pressure max. 15 bar.
  • Minimum and maximum fail safe field selectable.



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