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The OTT CBS meets or exceeds USGS standards for accuracy, and will not drift over time. It features outputs for SDI-12 and 420 mA.

Application: Surface water, Groundwater
Measurement technology: Bubbler-in
Product Highlights: Drift-free water level measurement - no pressure sensor or electronics in the water
Measurement range: 0 to 15 m or 0 to 30 m
Accuracy: ± 3 mm (high accuracy version); ± 5 mm (standard and 30 meter versions)
Internal data logger: No
Interface: SDI-12, RS-485 (using SDI-12), or 4 ...20 mA

  • Accurate—Meets and exceeds USGS guidelines for water level accuracy, and will not drift over time

  • Complete Solution—Combining the CBS with an EPS-50 bubble chamber reduces the influence of wave action and prevents unnecessary noise in your data
  • Low Maintenance—No desiccant, pump maintenance, or lubrication required
  • Easy-to-Start/Install—All programming can be completed using DIP switches; connect into existing platforms using 3/8' O.D. or 4mm O.D. measuring tube (no adapters required)
  • Compact Size—small and powerful pump motor generates the required volume of air to perform measurement.
  • Low Power—Intelligent pumping strategy compares the previous measurement to the actual pressure at the current measurement, and optimizes the pumping time depending on the difference (i.e., small changes in level are measured with very short pump cycles)


Water level measurement


Measuring range


Version ''Standard'' and

''USGS specification''

0 ... 15 m (0...50 ft)

Version ''30 m measuring range''

0 ... 30 m (0...100 ft)


1 mm (0.01 ft)



Version ''Standard'' and

''30m measuring range''

±5 mm

Version ''USGS specification''

0 ... 15 ft: ±0.01 %
15 ... 50 ft: ±0.065 % of measurement value or 0.02 ft, whichever is less


m, ft, bar, PSI

Electrical data



4 ... 20 mA, SDI-12, SDI-12 via RS-485

Power supply

10 ... 30 V DC, typ. 12/24 V DC

Current consumption


Measuring interval 1 min

typ. 320 mAh/day

Measuring interval 15min

typ. 25 mAh/day

Housing material


Dimensions L x W x H

165 mm x 205 mm x 115 mm


approx. 1,500 g

Protection class


Environmental conditions


Operating temperature

-20 ... +60 °C

Storage temperature

- 40 ... +85 °C

Relative air humidity

10 ... 95 %; not condensing

Measuring tube

2 mm or 4 mm ID

EMV - limit values

According to IEC61326 and EN61326

Related Categories
Aqualab Systems
Water Level Sensors