OBS-3+ & OBS300 Turbidity Sensors

The OBS-3+ is a submersible, turbidity probe that has sideways-facing optics while the OBS300 has downwards facing optics.

It uses OBS® technology to measure suspended solids and turbidity for applications ranging from water quality in freshwater rivers and streams to sediment transport and dredge monitoring. Campbell Scientific dataloggers measure the OBS-3+ probe's output and calculate turbidity.

Benefits and Features

  • Sideways or downwards facing opticsto suit the application
  • Measures suspended solids and turbidity for up to 4000 NTUs
  • Provides a compact, low-power probe that is field proven
  • Accurate and rugged
  • Compatible with all Campbell Scientific dataloggers
  • Stainless-steel body allows use down to 500 m in fresh water
  • Titanium body allows use down to 1500 m in fresh or salt water
  • Fitted with MCBH-5-FS, wet-pluggable connector-multiple mating cable length options available


Key Specifications

  • Drift: less than 2% per year
  • Maximum Data Rate: 10 Hz
  • Infrared Wavelength: 850 nm ±5 nm
  • Daylight Rejection: -28 dB (re: 48 mW cm-2)
  • Optical power: 2000 µW
  • Turbidity Accuracy: 2% of reading or 0.5 NTU (whichever is larger)
  • Housing material: 316 stainless steel or titanium
  • Maximum Depth:Stainless-Steel Body: 500m; Titanium Body: 1500 m
  • Output: Optional 2.5VDC, 0-5VDC or 4-20mA


We can now supply Amco Clear® Turbidity standards in a range of NTUs for calibration of OBS-3 series sensors. This is a safe, non-toxic and disposable alternative to Formazin. Please contact us with details of your requirements.

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OBS-3+ Brochure

File Size 527KB   Filename b_obs3plus.pdf   Download