Friday, 03 December 2021

Bob Level Measurement Unit

Suitable for silos up to 50 meters

Principle :

The Sondor measures the product height in a silo. It can work for any bulk product and does not require any adjustments after being put into operation. Easy to install, it is used in industries storing granular or powder bulk and particularly in difficult applications: important height, turbulence, temperature, clogging bulk.

Under automatic or manual (push button) operating conditions, the measuring tape, previously wound up on its pulley and ballasted with the counter-weight, goes down into the silo. When this counter-weight reaches the material, the motor stops and runs back. The inductive sensor located in front of the pulley generates pulses they are transformed by the PLC into an analog output.

Technical Characteristics :


The SONDOR III is divided into two separate tight compartments :

The electrical compartment :

  • The motoreducing gear
  • The static proximity detectors
  • The relays and thermal protection
  • The transformer and protection in the form of fuses
  • The PCB electronics or the PLC control compartment

The mechanical compartment :

  • A gear motor
  • A measuring tape in stainless steel
  • An adjustable and dismountable scraper
  • A sealing rubber cone
  • A removable attach between slope and counter weight
  • A counter-weight can be filled up with the product to be measured.

The shape of the mechanical compartment makes the discharge of dust possible during evacuation.


Start operation By push-button or
automatically frequency defined with customer
Output signal Analog output 0-10V
Analog output 4-20Ma
pulses or profibus communication
Defect signal General defect contact
Sequence safety Control of the total times, self monitoring of all data points and cycle initialization
Thermic controls (gear motor)
Initialization after defect
Measurement reliability Pulses counted on the way down are stored are counted on the way up and then compared. In case the difference exceeds 4 pulses, the measurement is not effective and a new cycle starts again.
Measurement accuracy Automatic corrections of the variable winding diameter according to the number of rounds
Oversank operation Automatic
Setting Full or empty
Inhibited height and total height
Temporization for starting
Programmation In our workshop


Max. measurement height 50 m
Resolution 1 pulse / 10 cm
± 1 impulsion
Probing speed 10 m/min
Protection IP55
Ambient temperature
from -20°C to +60°C
Working pressure 2 bars


Casing and flange Die cast aluminium
Dimensions 460 x 430 x 430
Mounting DN 100
Max. tensile strength 500 N
Breaking strength 1200 N
Strip Stainless steel with cleaning system and tightness rubber cone


Power supply 400 VAC tri or 230 VAC mons
Control voltage 24 VCC
Installed power 65 VA

Applications and References :

Advantages :

  • Easy installation and commissioning
  • Possibility of probe counter-weight filled up with the measured material
  • Measuring strip in stainless steel
  • Output signal by pulses, 4-20mA or 0-10V
  • Profibus communication (coming soon)
  • Cleaning system and tightness rubber cone

  • Options :

  • Cloth counter-weight (6 kg)
  • Special sun protection (for temperature)
  • Environment branch : refiom
  • Float counterweight in steel or polypropylene

  • Mineral Industry: cement, clinker, lime, plaster, calcium carbonate, fly ash, bentonite, sand, quarry, glass…
  • Food industry: cereals, pet food, sugar, salt, flour, chocolate…
  • Chemical industry: plastic…



9-12 November 2021 - Sertãozinho, SP (Brazil) :

Fenasucro & Agrocana, International Sugar Exhibition.


November 23-25, 2021, Online(Brazil) :

SEMTEC 7º Seminário Técnico da Indústria do Cimento e Cal


20-22 April 2022, Mackay Queensland (Australia) :

ASSCT 2022, 43th Sugar conference, exhibitor and poster presentation.