OBS501 Smart Turbidity Meter with Antifouling Features
Ideal for Heavy Sediment Load Environments
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications

Overview

The OBS501 features dual backscatter and sidescatter sensors, a shutter mechanism that keeps the lenses clean, and a refillable biocide chamber that prevents fouling–just like the OBS500. In addition, the OBS501 has improved performance in heavy sediment load environments. ClearSensor®  and OBS® are registered trademarks of Campbell Scientific.

The OBS501 is constructed to prevent sand grains or packed sediment from getting wedged between the shutter and sensor body, which inhibits the shutter’s movement. To do this, the OBS501's shutter and body were designed to eliminate parallel surfaces between moving parts wherever possible. The probe also uses a flushing action that moves the sediment down and out of the cavity behind the shutter.

The OBS501 can sense if the shutter’s motor is working harder than normal. If it is, the shutter moves slightly back and forth to dislodge sand grains before fully opening or closing. 

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Benefits and Features

  • Dual backscatter and sidescatter sensors used to measure turbidity
  • ClearSensor antifouling method for better measurements in biologically active water
  • Shutter/wiper mechanism keeps lenses clean
  • Refillable biocide chamber prevents fouling
  • Disposable plastic sleeve facilitates cleanup
  • Optional copper sleeve for additional protection (especially for sea water) or disposable plastic sleeve facilitates easy cleanup

Images

OBS501 in open and closed shutter positions
OBS501 in open and closed shutter positions
OBS501 in open and closed shutter positions
OBS501 in open shutter position
OBS501 in closed shutter position
OBS501 in closed shutter position with cable

Detailed Description

Design features of the OBS501 include the combination of a backscatter sensor (better at measuring high turbidity) with a second sidescatter sensor (better at measuring lower turbidity). It has a shutter that is opened only during measurements, which reduces the time that algae or other organisms can cling to its optics.

To prevent biofouling and ensure better measurements, the OBS501 incorporates the ClearSensor Method (Patent No. 8,429,952). This method uses a shutter/wiper mechanism to protect and clean the optics. With the ClearSensor method, a chamber is also filled with a biocide that continuously leaches out over the optics while the probe shutter is in the closed position.

(OBS® is a registered trademark of Campbell Scientific.)

Specifications

Dual Probe 90° side scatter and backscatter
Range 0 to 4000 NTU
Active and Passive Antifouling Shutter, wiper, biocide, copper, optional removable sleeve
Concentration Accuracy ±2% of reading or 0.5 NTU (whichever is greater)
Operating Temperature Range 0° to 40°C
Storage Temperature Range 0° to 40°C
Temperature Accuracy ±0.3°C
Emitter Wavelength 850 nm
Power Requirements 9.6 to 18 Vdc
Measurement Time < 10 s
Diameter 4.8 cm (1.88 in.)
Maximum Submersion Depth 100 m (330 ft)
Maximum Cable Length
  • 116 m (380 ft) for 1 channel SDI-12 or analog
  • 15 m (50 ft) for RS-232
Length 27 cm (10.63 in.)
Weight 0.59 kg (1.30 lb)

Power Consumption

Quiescent < 200 µA
Measurement < 40 mA
Communication < 40 mA
Active Shutter Motor < 380 mA

Outputs

SDI-12 Version 1.3, 1200 bps
RS-232 9600 bps
Analog 0 to 5 Vdc

Compatibility

Datalogger Considerations

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X CR6

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR5000 CR9000 CR7X

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