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CS471 Compact Bubble Water Level Sensor, High Accuracy
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The CS471 is a high-accuracy bubbler (±0.02 ft) that generally measures ground or surface water level, but can also measure any liquid level. A Campbell Scientific datalogger controls the CS471 pump and calculates the measurements. This compact bubbler typically communicates with the datalogger via the SDI-12 protocol. Many of our dataloggers support SDI-12.

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Benefits and Features

  • Ideal for areas where submersed sensors can be damaged due to corrosion, contamination, flood-related debris, lightning, or vandalism
  • Compatible with most Campbell Scientific data loggers
  • Easy to maintain
  • Robust pump design provides reliable operation
  • Consistent accuracy ensured by drift-free measurements and offset compensation using relative measurement
  • Purge function clears the measuring tube and the bubble chamber of contamination
  • Does not use pressurized nitrogen tank—requiring less frequent attendance
  • Existing tubes can be used


Detailed Description

The CS471 contains a piston pump that compresses air. The compressed air flows through a measuring tube into the water being measured. The pressure created in the measuring tube is directly proportional to the water column above a bubble chamber. The CS471 measures both barometric pressure and bubble pressure, one after the other. The height of the water above the bubble chamber is then calculated by taking the difference between the barometric and bubble pressure measurements.

To use the CS471, the acquisition system must include the measuring tube, a bubble chamber, power supply, datalogger, and datalogger-connection cable. Campbell Scientific offers the measuring tube, bubble chamber, and cable as Common Accessories. (See the Ordering Info on the web page.) The CS471, datalogger, and power supply must be housed in a desiccated environment, typically a Campbell Scientific enclosure. Hardware for mounting the CS471 to an enclosure backplate is shipped with the sensor.

The CS471 can communicate via SDI-12, 4 - 20 mA, or RS-485 (SDI-12 protocol via a physical RS-485 interface). SDI-12 is the preferred protocol when using Campbell Scientific dataloggers. Many of our dataloggers support SDI-12.


Resolution 0.003 ft /0.014 psi
Power Requirements 10 to 30 Vdc
Measurement Time 1 min
Outputs SDI-12 (version 1.3) 1200 Baud, 4-20 mA, RS-484 (SDI-12 Protocol via RS-485 interface)
Measurement Range 0 to 15.2 m (0 to 50 ft)
Operating Temperature Range -20° to +60°C
Storage Temperature Range -40° to +85°C
Relative Humidity Range 10% to 95% RH (non-condensing)
  • ±0.003 m (0.01 ft) at 0 to 4.6 m (0 to 15 ft)
  • ±0.065% of reading at 4.6 to 10.7 m (15 to 35 ft)
  • ±0.006 m (0.02 ft) at 10.7 to 15.2 m (35 to 50 ft)
Measurement/Communication Current (Typical)
  • 320 mAh/day (1-minute query interval)
  • 25 mAh/day (15-minute query interval)
Maximum Tube Length 100.6 m (330 ft)
Electronics Box Dimensions 16.5 x 20.5 x 11.5 cm (6.5 x 8.1 x 4.5 in.)
Weight 1.5 kg (3.3 lb)


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)
CR1000 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR9000 (retired)
CR9000X (retired)

Frequently Asked Questions

Number of FAQs related to CS471: 9

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  1. The measurement range is the same: 15.24 m (50 ft) of water. The CS471, however, is more accurate.

  2. No. These sensors do not need a gas bottle, and a pump is included with them.

  3. Place the CS470 or CS471 above the high-water mark, and run the tubing into the water. Because the tubing is the only portion of the sensor in contact with the water, the sensor itself won’t be damaged by the current. It may be necessary, however, to replace damaged tubing occasionally.

  4. Terminate the tubing in a stilling well to greatly mitigate the effects of deposition. If this is not possible, use pn 25502, OTT EPS-50 Bubble Chamber

  5. The smallest enclosure that will accommodate these items is our ENC14/16.