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Dwyer OLS Optical Level Switch

Dwyer OLS are optical level switches. These low cost, compact instruments provide a transistor style switch output in the presence (or absence) of liquid.  Technology is via IR light refraction in the presence of liquid.  Dwyer OLS level switches have no moving parts and are available in a variety of wetted materials including 316SS, polysulfone and PFA. Local LEDs indicate the presence or absence of liquid along with transistor output.  Compact switch can be quickly mounted horizontally or vertically for each installation (take care to avoid air bubbles etc on pipe installs).


Dwyer OLS switches are ideal for leak detection systems and are unaffected by liquid density.  Coverage of the sensor is required to tigger, approx 5mm


Dwyer OLS Optical Level Switch Specifications

  • Service: Non-coating and material compatible liquids.
  • Wetted Materials: See datasheet download below.
  • Temperature Limits:
    • Process: OLS-10 and OLS-11: up to 93.3°C, OLS-12:  up to 48.9°C;
    • Ambient: OLS-10 and OLS-11: up to 79.4°C, OLS-12: up to 48.9°C.
  • Pressure Limit: OLS-11 and OLS-12: 200 psig (13.8 bar); OLS-10: 1000 psig (69 bar).
  • Repeatability:±0.5 mm
  • Switch Type: NPN open collector.
  • Power Requirements: 10 to 28 VDC.
  • Output Signal: Vout (max.) = 28 VDC, Isink (max.) = 100 mA.
  • Current Consumption: 35 mA max.
  • Electrical Connections: 965 mm long 3 conductor cable, 22 AWG wire.
  • Process Connection:1/2″ male NPT.
  • Mounting Orientation: Can be mounted in any position.
  • Specific Gravity: No minimum.
  • Weight: 3 oz (85g).


Fluidic are a recognised partner of Dwyer Instruments for Scotland and the North of England.  Our instrumentation engineers are product trained and are able to help with instrument selection.  Please call either office for more information or to discuss your requirements. (Glasgow 0141 641 5920,  Warrington 01925 572401).


  • Download Dwyer OLS Level Switch Datasheet
  • Download Dwyer OLS Level Switch Manual
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