SD Series Optical Level Switch

The SD Series optical level switch uses the principle of light reflection in a prism to sense the absence or presence of a liquid at the point where the sensor is installed in a tank, pipeline or other type of container.


SD series is an optical level switch line that emit a beam of infrared light into the tip (prism) of the sensor. In the absence of the liquid at the sensor tip the light is reflected back to the sensor’s receiver. When the target liquid is present surrounding the sensor tip, the light is refracted into the liquid and away from the SD series level switch receiving component thus how liquid presence and absence is determined. The SD series output will be activated accordingly. These optical level switch devices are compact, cost-effective and ideal for a wide variety of fluids.


  • Simple and compact with no moving parts
  • LED indication
  • 10-28VDC, 115VAC or 230VAC powered versions
  • Solidstate NPN/PNP or relay output
  • Operating temperatures up to 257⁰F (125⁰C)
  • Wide range of use in machine systems for a variety of liquid level detection
  • Unique SD22 design, switch body and tip disconnects



  • Machine protection of fluid levels
  • High and low level detection in air conditioning chiller systems
  • Maintain reservoir level in hydraulic systems
  • Automotive systems


  • HVAC
  • Pharmaceutical
  • Process industries
  • Automotive
  • Others


Datasheet: EN