RSS-2-300WL Flow Meter

The Geolux RSS-2-300 WL flow velocity and level meter uses radar technology to provide precise, contactless measurement of surface flow velocity, and to measure the distance from the sensor to the water level. Contactless radar technology enables quick and simple sensor installation above the water surface, and requires minimum maintenance.

RSS-2-300 WL flow meter is used to monitor flow velocity and water level in open channels such as rivers, irrigation channels or sewer systems, and for monitoring and controlling hydropower plants and wastewater treatment plants. The flow meter is also suitable for various mass flow metering applications in mining processing plants, industrial installations, and, due to operation without moving parts and robust mechanical design, is ideal for measurement of flammable fluids and harsh chemical applications.

The surface velocity radar operates in the K-band (at 24.125 GHz), and provides 20 flow speed readings per second over serial (RS-232, RS-485) and CAN interfaces. The level radar sensor operates in the W-band, between 77 GHz and 81 GHz.
A variety of supported communication interfaces and protocols enable easy integration with existing telemetry equipment and SCADA systems. The integrated tilt sensor measures inclination angle of the sensor and the flow velocity measurement is automatically cosine-corrected according to the measured mounting tilt angle.
Geolux RSS-2-300 WL instrument is certified according to both European and American standards, and is being used worldwide.


Surface Velocity Radar Type K-band 24.125 GHz Doppler radar, 21 dBm EIRP
Surface Velocity Radar Beam Angle 12° Azimuth
24° Elevation
Level Radar Type W-band 77-81 GHz FMCW radar
Level Radar Beam Angle
Detection Distance 15 m / 30 m
Speed Range 0,02 m/s to 15 m/s
Speed Resolution 0,001 m/s
Speed Accuracy 1%
Level Resolution 0,5 mm
Level Accuracy +/-2 mm
IP Rating IP68


Electrical & Mechanical 

Power Input 9 to 27 VDC
Power Consumption 1,3 W operational; 0,235 W standby
Maximal Current < 750 mA
Temperature Range -40°C to +85°C
(without heating or coolers)
Device Outer Dimensions 150mm x 200mm x 250mm



Serial Interface 1 x serial RS-485 half-duplex
1 x serial RS-232 (two wire interface)
Baud Rate 1200 bps to 115200 bps
Serial Protocols Modbus/RS-485, GLX-NMEA, ASCII-S
other available on request
SDI-12 Interface Available
Analog 4-20mA Interface Available



EN 61326-1:2013
ETSI EN 301 489-1
ETSI EN 301 489-3
EN 301 489-3 V2.1.1:2019
EN 301 489-1 V2.2.3:2019
EN 300 440 V2.2.1:2018
EN 62368-1:2014+A11:2007;
EN 60950-22:2017
EN 61010-1:2010
FCC Part 15 class B