Ask The Experts Need Help? Ask The Expert Call us today on +44(0)1236 459020

Optomax Industrial Glass Range of Liquid Level Switches

Optomax Industrial Glass Range of Liquid Level Switches which are Often Single Point, Can Operate In High Pressure, High Temperature, Aggressive Environments Due To Their Stainless Steel And Glass Construction While Offering Industrial Supply Voltages And Outputs That Can Directly Drive Loads.
The microcontroller based Optomax Industrial Glass Range of single point Liquid Level Switches are solid state, incorporating an infra-red LED and phototransistor which are optically coupled by the tip when the sensor is in air. When the sensing tip is immersed in liquid, the infra-red light escapes making the output change state. The sensor can detect the presence or absence of almost any liquid type; oil or water based. It is insensitive to ambient light and is not affected by foam when in air or by small bubbles when in liquid.

A range of N and P type output configurations can sink or source up to 1A at supply voltage ranges from 4.5 to 15.4Vdc or 8 to 30Vdc and can be configured to output a high or low signal in either a wet or dry state. Options for connecting to inductive loads or digital interfaces are also available.

The 316L stainless steel single point liquid level switch can operate up to 600 bar (8700 psi) with housing threads suitable for external sensor mounting and for use in operating temperature range -40 to 125°C.

Samples for the Optomax Industrial Glass range of liquid level switches are available on request for this product. For high volume production orders, please contact us.


Ask the expert

Part Numbering Guide


Supply Voltages (Vs) 4.5 to 15.4Vdc
or 8 to 30Vdc
Supply Currents (Is) 2.5mA max. (Vs = 4.5 to 15.4Vdc)
or 7.5mA max. (Vs = 4.5 to 30Vdc)
Output Sink and Source Current (Iout) 1A
Operating Temperatures -40 to +125°C
Storage Temperatures Standard: -40 to +125°C
Housing Material Stainless steel housing with glass sensing tip
Sensor Termination 20AWG, 250mm PTFE wires, 8mm tinned
Operating Pressure Up to 600 bar depending on housing type




Output Voltage (Vout): Iout = 1A
Vs = 4.5 to 15.4Vdc
Output High Vout = Vs – 1.5V max
Output Low Vout = 0V + 0.5V max
Output Voltage (Vout): Iout = 1A
Vs = 8 to 30Vdc
Output High Vout = Vs – 1.8V max
Output Low Vout = 0V + 0.7V max


Wire Designation
Red Vs
Green Output*
Blue 0V

*See part numbering guide for output type and logic




  • Reverse polarity, ESD and transient over-voltage protected
  • Wide supply voltage ranges
  • N and P type output configurations, capable of sinking or sourcing up to 1A, can directly drive loads
  • Standard and extended temperature ranges available
  • Stainless steel housing with glass sensing tip
  • Thread options for external mounting
  • Very high operating pressure


  • Solid state so no moving parts to cause unreliability
  • Small in size so they can be installed in applications where space is limited
  • Can detect tiny amounts of liquid when positioned correctly, ideal for leak detection
  • Fast response time
  • Repeatable switching point
  • Built-in output delays available on request for applications where sloshing causes intermittent switching
  • Very robust construction permitting use in a wide range of demanding applications
  • Compatible with most fluids and chemicals


Liquid sensing 001_450

When in air the infrared light is reflected back to the detector


Liquid sensing 002_450

When in liquid the infrared light is refracted and the output switches

  • This field is for validation purposes and should be left unchanged.