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 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

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) 12º
Power Requirements 5.4 to 28 VDC
Power consumption in active mode
Power consumption in rest mode
Interfaces 4-20 mA, SDI-12, RS-485 (SDI-12 Protocol)
Housing ASA (UV-stabilized ABS)
Radom (front plate) TFM PTFE
Mounting bracket 1.4301 (V2A)
Lateral axis ±90º
Longitudinal axis ±15º
Dimensions 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)


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