Top Mounted Float Operated Level Transmitter

Principle of Operation :

Level transmitter works on the principle of reed resistance/permanent magnet basis. Reedswitches function like the center arm (as shown in fig. 1) of a potentiometer. As per liquid level float moves up or down, magnet inside the float operates the reedswitches thereby causing a change in resistance value. Change in the resistance is measured by the electronics unit and conditioned as a current output of 4 to 20 mA. Signal conditioner is head mounted and of 2-wire loop powered suitable for 12 to 24 VDC giving output of 4 to 20 mA.

Technical Specification : Our Standard Product

Model (VMT-04-F65-AW) , (VMT-04-F92-AW) top mounted magnetic reed/resistance cascade type loop powered 2 wire level transmitter. Process Connection flange 78 or 120 mm diameter with 4 bolt holes of 6mm or 14 mm dia on 65 or 92 mm PCD respectively. Wetted parts flange & float stopper in SS 304. Float material SS 316L and diameter 41, 53 or 68 mm. Operating pressure 10kg/ and Temperature 125 deg.C. maximum.

Specific Gravity Suitable Down to 0.7 (Upto 0.5 optional)
Range 0-150 mm upto 0-3000 mm.
Resolution Betterthan ±10 mm.
Span Suppression Max. 25% of Span
Zero Elevation Max. 25% of Span
Excitation Voltage 12 - 36 V DC
Loop Resistance Max. 600 OHMs.

Salient Features :

  • Reedswitches are hermetically sealed-in glass under an inert gas and therefore protected from contamination.
  • Reedswitches used by us are suitable for maximum working voltage of 150 VDC and current 1 Ampere. But in our circuitry they are subjected to maximum of 3 VDC and current 1 mA in case of resistance output and maximum of 24 VDC and 20 mA when used in conjunction with a signal conditioner for current output. This ensures long life of the product.
  • Reedswitches are UL approved and ISO certified for quality management.
  • Operating temperature range of reedswitches are -40 deg. C. to 125 deg. C.
  • Reed Switches are enclosed in a moulded glass filled nylon capsule and therefore protected from mechanical shocks or damage. Moreover the stainless steel float-guide pipe, containing the PCB of reedswitches and resistances, is solidly filled with MgO Powder. Hence this is suitable for sub zero temperatures.
  • Reedswitches are protected against mechanical damage and contact corrosion & vibration.
  • Since an outer protection tube is provided (for applications like LPG, where external cage is not possible) the reedswitch sensor assembly can be replaced without disturbing the process.
  • Since the float is of 200mm dia with specific gravity -0.4 (for LPG) it will have higher buoyant force. For standard applications float shall be of 48 mm Or 68 mm in diameter.
  • Above all float is the only moving part. No wear and tear.
    • Application :

      • Applicable in environment with high temp., high pressure, strong acid, strong alkaline and hazardous locations.
      • Multiple applications for textile dyeing, sewage water processing, power generating, boiler and petrochemical industries.


      Level Indicators are of light weight, compact, rugged & field proven. All Indicators are provided with span & zero adjustment. Current consumption shall be between a few Microamperes to Milliamperes depending upon the model.

      LED Type Level Indicators Model LLI-10 & LLI -12
      Overall Dimension 48 x 96 x 60 or 110 mm
      Input Signal 3-wire-Resistance from Transmitter (Resistance Value depends on Range)
      Display 3 mm dia LED-11 nos- 10 for Level and 1 for Power On.
      Range 0 to 100%, in 10 equal steps of Height i.e, Millimetres or Litres
      Mountin Flush Panel or Projection
      Level Indicator Model DPI-480
      Overall Dimension 48 x 96 x 60 or 110 mm
      Mains Power Supply 230 VAC / 24 VDC
      Input Signal 4 to 20 mA
      Loop Supply 24VDC - Built in
      Display 0.5" Seven Segment LED, 3 1/2" or 4 digits.
      Unit of Display 0-100%, Millimetres, Litres as required
      Mounting Flush Panel
      Level Indicator Model DPI-48
      Overall Dimension 48 x 96 x 60 or 110 mm
      Mains Power Supply 230 VAC / 24 VDC
      Input Signal Resistance
      Display 0.5" Seven Segment LED, 3 1/2" or 4 digits.
      Unit of Display Millimetre i.e., Height of Liquid column.
      Mounting Flush Panel
      Level Indicator Controller Model LC 504/2F
      Overall Dimension 96 x 96 x 110 mm
      Mains Power Supply 230 VAC /12 or 24 VDC
      Input Signal 4 to 20 mA
      Display 0.5" Seven Segment LED, 3 1/2" or 4 digits.
      Unit of Display 0-100% /Millimetres / Litres
      No of Set Points 2
      Set Point adjustment Push Button / Potentiometer
      Output 2 change over Relay contacts-rated 5 Amps at 230 VAC resistive.
      Mounting Flush Panel