NON-CONTACT DISCHARGE RADAR RQ-30 / RQ-30A

NON-CONTACT DISCHARGE MEASUREMENT BY MEANS OF RADAR TECHNOLOGY FOR OPEN RIVERS

The RQ-30 is a sensor for continuous discharge measurement of rivers, open channels, and canals with known cross-section profiles. The sensor uses innovative radar technology to measure velocity, water level, and discharge. It enables reliable, non-contact measurement without the need for structural work in the water.

FEATURES AND ADVANTAGES

Non-contact, maintenance-free measurement system
No structural work is necessary for the water
No threat to the system through flooding
Low power consumption enables operation using solar cells
Recognition of flow direction
Measuring range 0.08 … 16 m/s (depending on the flow conditions)
Recognition of hysteresis-effects
Measurement in backwater situations
Measures even where weed growth prevails and the sensor is not affected by turbidity
Measurement in tidal waters
Automatic angle measurement
Optional (RQ-30a): analog outputs from 4 to 20 mA

Description

FIELDS OF APPLICATION

The RQ-30 enables discharge measurement for rivers, streams, open channels, and canals for which continuous monitoring is desired. Thanks to the non-contact radar technology the measuring equipment is not susceptible to contamination, debris, or driftwood in the water. Furthermore, the non-contact measurement warrants very low maintenance and fail-safe operation, especially during high water or flooding.

IMPLEMENTATION

The sensor can be simply mounted on bridges, on the roofs of closed canals or on channel superstructures. The bed of the water should be as stable as possible in order to warrant consistent measurement. A visible swell must be evident on the surface of the water.

MEASURING PRINCIPLE

The non-contact radar technology determines the water surface flow velocity using the Doppler frequency shift method and furthermore, the water level is established by a travel time measurement. With a known cross section profile the discharge Q of the water can then be calculated on the basis of the continuity equation: Q = vm · A (h)

TECHNICAL DETAILS

GENERAL

Dimensions 338 mm x 333 mm x 154 mm
Total weight 5.4 kg
Protection class IP 67
Power supply 6 … 30 V
Power consumption at 12V standby approx. 1mA; active operation approx. 140mA
Operating temperature -35 … 60°C
Miscellaneous over-voltage protection, reverse power protection, lightning protection

WATER LEVEL MEASUREMENT

Measurement range 0 … 15 m standard version / 0 … 35 m extended version
Resolution 1 mm
Radar frequency 26 GHz (K-Band)
Radar opening angle 10°

VELOCITY MEASUREMENT

Measurement range 0.08 … 16 m/s (depending on flow conditions)
Accuracy +/- 0.01 m/s; +/- 1 % FS
Resolution 1 mm/s
Direction recognition +/-
Measurement duration 5 … 240 sec.
Measurement interval 8 sec. … 5h
Measurement frequency 24 GHz (K-Band)
Radar opening angle 12°
Distance to water surface 0.50 … 35 m
Necessary minimum wave height 3 mm

AUTOMATIC VERTICAL ANGLE COMPENSATION

Accuracy +/- 1°
Resolution +/- 0.1°

INTERFACE

Analogue Output (RQ-30a) 4 x output 4 – 20 mA for water level, velocity, discharge, and AUX
Digital Interface 1 x SDI-12; 1 x RS 485 or Modbus
- Transfer rate: 1.2 to 115.2 kBd
- Protocol: various ASCII-protocols
- Output: water level, velocity and discharge, quality parameters