Level sensing guide

Level sensing employs many different techniques to determine how full or how empty a container actually is. Applications vary from industry to industry and the choice of which sensor to use needs careful consideration. The basic function of level sensors is to communicate when to open or close control valves.

The choice of sensor is usually determined by which substance is being measured, the environment in which the sensors is to used and in which position the sensor needs to be mounted.

Some of the most common level sensors are described below:

Float switches

  • Various options available - top & side mount, cable and submerged
  • Basic full/empty type level indication set by mounting position
  • Cost effective and simple to install
  • Often can't switch inductive loads directly - use interface relay
  • Float material to liquid compatibility must be checked

See our range of float switches 

Capacitive level switches

  • Barrel (side mount) and probe (top mount) formats
  • Basic full/empty type level indication set by mounting position
  • Accurate switching even with heavy residue build-up
  • High reliability due to no moving parts
  • Can often be used with liquids and powder or granular product

See our range of capacitive level switches

Vibrating level probes

Uses high frequency vibrations which are damped by product contact to sense level

  • Fork and road designs available to suitable media
  • Basic full/empty type level indication set by mounting position
  • Very reliable, with self-monitoring features built-in
  • Sensing of liquids, pastes, grains, powders, sand and other granular products possible

See our range of vibrating level switches

Conductive level switches

  • Uses stainless steel probes to provide sensing for up to 3 switch points
  • Can only be used with conductive fluids
  • Used in conjunction with a level control relay to set & monitor switching points
  • Once installed switching points can be easily adjusted via relay controls

See our range of conductive level probes

Ultrasonic level sensors

  • Ultrasonic sound pulses are reflected by the surface of the liquid
  • Non-contact level sensing of water, emulsions, oils, chemicals and effluent
  • Provides proportional indication of level via a 0/4-20mA or 0-10V output
  • Typical range 0.25 to 10m
  • Provides accurate level indication, but can be affected by dust or foam
  • Can be used with solids, but range reduced by 50%

See our range of ultrasonic level sensors