Services Available | |
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Repair | No |
Calibration | No |
Free Support | Yes |
The OBS-3+ is a submersible turbidity probe that has sideways-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 data loggers measure the OBS-3+ probe's output and calculate turbidity.
Read MoreThe OBS-3+ uses its sideways-facing optics to emit a near-infrared light into the water. It then measures the light that bounces back from the water’s suspended particles.
If an obstruction is in the emitted light’s range, the light will scatter back and the turbidity reading will be too high. This probe's sideways-facing optics avoids obstructions above and below the probe. The OBS300 is available for locations that have obstructions around the sides of the probe.
OBS® is a registered trademark of Campbell Scientific.
Range |
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Maximum Submersion Depth |
|
Concentration Accuracy |
|
Maximum Concentration Range |
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Operating Temperature Range | 0° to 40°C |
Drift over Time | < 2% per year |
Maximum Data Rate | 10 Hz |
Minimum Warm-up Time | 2 s |
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 |
Connector | MCBH-5-FS, wet-pluggable |
Diameter | 2.5 cm (0.98 in.) |
Height | 14.7 cm (5.79 in.) |
Weight | 181.4 g (0.4 lb) |
-2.5 Output Option |
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Output Voltage | 0 to 2.5 V (over selected NTU range) |
Supply Voltage | 5 to 15 Vdc |
Current Drain | 15 mA |
-5 Output Option |
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Output Voltage | 0 to 5 V (over selected NTU range) |
Supply Voltage | 5 to 15 Vdc |
Current Drain | 15 mA |
-20 Output Option |
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Output Voltage | 4 to 20 mA (over selected NTU range) |
Supply Voltage | 9 to 15 Vdc |
Current Drain | 45 mA |
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
Product | Compatible | Note |
---|---|---|
21X (retired) | ||
CR10 (retired) | ||
CR1000 (retired) | ||
CR10X (retired) | ||
CR200X (retired) | ||
CR206X (retired) | ||
CR211X (retired) | ||
CR216X (retired) | ||
CR23X (retired) | ||
CR295X (retired) | ||
CR300 | ||
CR3000 (retired) | ||
CR310 | ||
CR500 (retired) | ||
CR5000 (retired) | ||
CR510 (retired) | ||
CR6 | ||
CR800 (retired) | ||
CR850 (retired) | ||
CR9000 (retired) | ||
CR9000X (retired) |
Number of FAQs related to OBS-3+: 19
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This has not been tested; however, it is likely that, as the sensor moves through the water, disturbances or bubbles are created that could distort the turbidity measurements.
The beam divergence angle of the sensor is 42°. (Within this 42° cone, 95% of the beam power is contained.)
These devices employ optical backscatter to measure light absorption and should produce comparable data, but variation is likely between sensors.
The accuracy is 0.5 NTU or 2% of reading.
The OBS-3+ and the OBS300 are essentially the same sensor but with differing optic placement. The OBS-3+ has sideways-facing optics, whereas the OBS300 has downward-facing optics.
Sensors are calibrated at the factory for measurements up to 4,000 NTUs, if requested at the time of order. Sensor ranges cannot be adjusted outside the factory.
This sensor is available with two types of wipers.
Short Cut does not allow mV readings. To record the raw mV data before it is converted to NTU, open the Short Cut file in the CRBasic Editor, and alter the program manually.
The following are some suggestions:
This depends on the turbidity of the water. In very clear water exposed to direct sunlight, up to 18 in. of water may be needed to prevent the sun from affecting the readings. Less sunlight penetrates more turbid water, which means the sensor would not need to be positioned as deeply. If the target water is clear and shallow, it may be necessary to construct a canopy above the water to shadow the monitoring site.
In addition, the sensor must be positioned in the water so that nothing obstructs its field of view. In very clear water, this may require an 18 in. standoff.
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