Radar level sensor

Part # ottrls

ott rls

The OTT RLS Radar Level Sensor is a non-contact radar level sensor that is ideal for measuring surface water in remote or hard to reach locations. The RLS accurately and efficiently measures surface water level at an accuracy of ±0.01 ft. Approximately 16 individual measurements are conducted each second and averaged after 20 seconds to minimize the influences of waves.

The RLS offers a large measurement range with a small blanking distance and narrow beam width. The sensor is easily connected to most data loggers via SDI-12 or 4-20 mA interfaces. The RLS has extremely low power consumption and is ideal for remote or solar powered sites.

  • ±0.01 ft accuracy for water level measurements, will not drift over time
  • measurements available every 20 seconds
  • unaffected by air temperature, wave action, humidity, flood events, floating debris, or contaminated water
  • requires only 12 mA @ 12V
  • can be mounted to slanted surfaces

What's the Easiest and Quickest Way to Start Collecting Data and Access it Anywhere?

The Answer's in the Cloud.

eTracker is a cellular modem and "virtual" cloud-based data logger in one (meaning you don't need to install a separate data logger). Simply connect your sensor and a power source to eTracker and you're done. Configure (or reconfigure) anytime from any Internet-connected device, and use Stevens-Connect to retrieve your data, or forward it to your favorite software system.

Technical Specifications

Measuring range

1.3-115 ft.

Transmitting Frequency

25.2 GHz Pulse Radar (FCC Version)

Resolution SDI-12 output

0.01 ft

Accuracy (SDI-12)

1.3-6.6 ft: ±0.03 ft 6.6-98.5 ft: ±0.01 ft 98.5-115 ft: ±0.03 ft

Average temperature coefficient (-10 … +40 °C, SDI-12)

0.01 % full scale/10 K

Accuracy (4-20 mA)

±0.1 % full scale

Average temperature coefficient (4-20 mA)

10 ppm full scale/°C (at 20 °C)

Measuring time

20 s

Beam angle of antenna (width of beam)


Power Requirements

5.4 to 28 VDC

Power consumption in active mode

< 15 mA @ +12 V equal to <180 mW

Power consumption in rest mode

< 0.05 mA @ +12 V equal to <0.6 mW


4-20 mA, SDI-12, RS-485 (SDI-12 Protocol)


ASA (UV-stabilized ABS)

Radom (front plate)


Mounting bracket

1.4301 (V2A)

Lateral axis


Longitudinal axis



8.7 in. (L) x 6.0 in. (W) x 7.5 in. (H)

Weight (incl. mounting bracket)

4.6 lbs

Operating temperature

-40 °C to +60 °C

Storage temperature

-40 °C to +85 °C

Operating humidity

0 to 100%

Environmental protection

IP67 (submersion depth max. 1 m; submersion duration max. 48 h)