Water Level Sensors

RLS 500

Reliable, non-contact water level monitoring

The Ott RLS 500 is a high accuracy radar sensor designed for continuous, non-contact water level measurement.

Using advanced 80 GHz FMCW radar technology, the RLS 500 measures the distance between the sensor and the water surface without any components being submerged. This reduces exposure to sediment, debris, biological fouling and aggressive water conditions.

With a measuring range of up to 30 metres, ±2 mm accuracy and extremely low power consumption, the Ott RLS 500 is ideal for permanent monitoring stations, flood warning networks and remote installations.

Applications

• Reservoirs and lakes
• Flood warning stations
• Stormwater monitoring
• Tidal and coastal monitoring
• Weirs and hydraulic structures
• Irrigation channels
• Water resource monitoring
• Remote and off grid stations
• Hydrological discharge calculation

Precise water level data without water contact

The Ott RLS 500 measures the distance to the water surface using frequency modulated continuous wave radar technology.

Because the sensor is installed above the water, it does not require a pressure sensor, float or other measurement component to be submerged. This protects the measurement system from many of the problems associated with sediment, contamination, corrosion and biological growth.

The result is dependable water level data with reduced maintenance and fewer disruptions to long term monitoring records.

Advanced 80 GHz radar technology

Operating within the 77 to 81 GHz frequency band, the RLS 500 produces a narrow 8° radar beam. The focused beam helps isolate the measurement area and supports installation at sites where bridge structures, channel walls or other nearby objects may otherwise interfere with the measurement.

The high frequency radar technology provides stable measurements across a distance to water range of 0 to 30m.

Reliable monitoring in demanding environments

The RLS 500 features a robust IP67 enclosure designed for long term outdoor deployment.

The lower section of the housing can withstand temporary flooding to a depth of 1 m for up to one week without damage. Durable housing materials and a UV stabilised exterior support operation in exposed monitoring locations.

The sensor operates across a temperature range of −40°C to +70°C, provided the measurement surface remains free of ice.

Designed for remote and off grid stations

The RLS 500 operates from a 5.5 to 28.8 V DC power supply, with 12 V and 24 V systems typically used.

Power consumption is less than 4 mA while active and less than 250 µA while idle. This makes the sensor well suited to battery and solar-powered monitoring stations where energy efficiency is essential.

Flexible measurement and data processing

The RLS 500 can provide direct water level or depth-to-water measurements. It can also process measured values within the sensor before transmission.

Available value-processing functions include:

• Mean value over a selected period
• Minimum value within an interval
• Maximum value within an interval
• Median value over a selected period
• Standard deviation over a selected period

The sensor can also provide hydrological discharge as a derived parameter when correctly configured for the monitoring structure and site.

Easy integration into monitoring networks

Industry standard communication interfaces support integration with Ott, Sutron and compatible third party dataloggers.

Available interfaces and protocols include:

• SDI-12
• RS-485
• SDI-12 version 1.4 over RS-485
• Modbus RTU over RS-485

This flexibility allows the RLS 500 to be incorporated into new monitoring stations or used to upgrade existing networks while preserving established data workflows.

This product is manufactured by Ott and proudly represented by Aqualab Scientific.