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OBS- 5+ Sediment & Pressure Measurement System

The OBS-5+ system monitors high sediment concentrations using an infrared laser and a proprietary dual photo-detection system. The probe transmits sediment concentration and depth to a PC via RS-232 or RS-485, data can also be recorded internally.  


The OBS-5+ has a graphical user interface (GUI) which enables the user to generate and store sediment calibration tables, program data logging and sampling schemes, as well graphically display data.


An operator can also use the GUI to calibrate the OBS-5+ with sediments, optimise resolution by changing the electronics gain to, and create up to 15 unique sediment lookup tables, which can be stored in FLASH memory for future use. The entire calibration process can be completed without spreadsheet calculations or curve fitting.



Monitors sediment concentrations up to 200 g/l (specific gravity 1.30)
Logs instrument depth
Records 200,000 scans of data in FLASH memory
Runs as long as six months on three alkaline C cells
Supports RS-232 and RS-485 data links
Compact 380 mm (15”) by 60 mm (2.4”) package





Monitor dredging and site remediation operations
Determine dredge efficiency
Undersea mining and trenching
Sediment transport research


Technical Specifications


Infrared Wavelength: 780 nm
Scattering Angles (clean water): 105° to 165°
Over Time: <30 ppm per month
Over Temperature: <200 ppm per °C
Maximum Sampling Rate: 25 Hz
Maximum Data Rate: 2 Hz
Data Capacity: 8 Mbytes
Maximum Number of Data Lines: 200,000
Battery Capacity: 8 Ahr
Life (maximum): 3,000 hrs
External Supply Voltage: 6 to 18 Vdc
External Supply Current: 55 mA
PC Interfaces: RS-232/115 kbps, RS-485/115 kbps
Maximum Depth: 300 m (984 ft )
Measurement Ranges
Concentration (depends on sediment type)
Mud (D50 = 20 μm): 0 to 50 g/l
Sand (D50 = 250 μm): 0 to 200 g/l
Pressure: 0 to 10, 20, 50, 100, or 200 m
Turbidity: 0.4 to 1,000 NTUs
Sediment Concentration
Mud: 2% of reading
Sand: 4% of reading
Turbidity: 1.5% of full scale
Pressure: 0.5% of reading
Connector: MCBH-8-FS, wet-pluggable
Wetted Material: 316 stainless steel, Delrin, and
20% GF polycarbonate
Temperature Range
Operating: 0° to 40°C
Storage: -20° to 70°C
Weight: 2.04 kg (4.5 lbs)
Weight (submerged): 1.02 kg (2.3 lbs)
Dimensions: 2.4" (6.0 cm) X 15" (38.0 cm)

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