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.Read More
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.)
|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|
|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||
|Length||27 cm (10.63 in.)|
|Weight||0.59 kg (1.30 lb)|
|Quiescent||< 200 µA|
|Measurement||< 40 mA|
|Communication||< 40 mA|
|Active Shutter Motor||< 380 mA|
|SDI-12||Version 1.3, 1200 bps|
|Analog||0 to 5 Vdc|