Turbidity Sensors / OBS-3-L
This product is no longer available.
OBS-3-L D&A Instrument Company Turbidity Monitor
Services Available
Repair No
Calibration No
Free Support No


The OBS-3 measured both turbidity and suspended solids. Its turbidity range was 0 to 4000 NTU. A nearly linear response to particle concentrations of turbidity spanned more than three orders of magnitude. (OBS® is a registered trademark of Campbell Scientific.)



Non-Linearity of Turbidity 2% (formazin, 0 to 2000 FTU)
Drift < 5% (per year)
Settling Time < 1 s
Input Voltage 9 to 16 Vdc
Infrared Wavelength 875 nm
Maximum Depth 500 m (1640.5 ft)
Diameter 3 cm (1.2 in.)
Length 18 cm (7.1 in.)
Weight 181.4 g (0.4 lb)


Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR800 (retired)
CR850 (retired)
CR9000 (retired)
CR9000X (retired)


Case Studies

New Zealand: Coal Mine Water Quality Monitoring
High-grade coal has been mined on the West Coast of New Zealand since the 1870s.......read more
Southeastern U.S.: Sediment Production Study
D & A Instruments (now part of Campbell Scientific) assisted the USDA National Sedimentation Laboratory......read more

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