Raven-Eye 2®

Raven-Eye 2®


The RAVEN-EYE® is the newest non-contact RADAR area/velocity flow meter for open channel flow measurements from Flow-Tronic. It combines state of the art non-contact radar measuring technology which measures flow from above the water surface with easy integration into existing SCADA or telemetry systems.

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The RAVEN-EYE® has been designed for flow measurement in municipal wastewater and stormwater sewers and easily adapts to a wide range of
applications. Being positioned above the water surface, the RAVEN-EYE® avoids thereby all problems (grease, fouling, corrosive liquids) associated with traditional flow meters where the sensor is immersed in the fluid.

The flexibility of the system and the wide range of mounting equipment make it really easy to install the sensor without specific engineering works and is ideal for retrofitting. The RAVEN-EYE® can be mounted in an existing manhole or under a bridge avoiding personnel to have contact with the flow.

Surcharge Conditions
The RAVEN-EYE® can be combined with optional surcharge velocity sensors and depth sensor in case a continuous measurement is required when the flow changes from open channel flow to surcharged flow

No Maintenance
Maintenance is completely removed as the sensor is not in contact with the flow. The RAVEN-EYE® builds on years of experience measuring sewer flows, the sensor is totally sealed, no joints, seals, screws or washers are used. It’s rated to IP68 which means it withstands surcharge events and aggressive atmospheres. Internal sensors monitor and report the condition or “health” of the system (auto-diagnostic system).

The combination of these benefits and virtually zero maintenance requirements, give the user a very low “Cost of Ownership”.

How does it work?
The RAVEN-EYE® is mounted above the water surface and measures the flow velocity at the water surface using a pulse wave radar and the flow depth with a level sensor (ultrasonic, radar or pressure). The flow
rate is calculated by applying the continuity equation:

Q = V x A

During each measurement cycle, the RAVEN-EYE® makes thousands of individual velocity measurements which are analyzed and processed into an extremely accurate average velocity measurement reading using a dedicated digital signal processor making realtime spectral analysis. Average velocity is calculated within the sensor by analyzing the surface velocity distribution and using a self-learning technology that doesn’t require theoretical modules nor site calibration.





  • Size: (HxWxL) 183 x 140 x 422 mm
  • Weight: 3,85 kg (without cable, level sensor and mounting accessories)
  • Materials Enclosure: Polyurethane (PU), stainless steel
  • Cable: Polyurethane jacketed
  • Cable Lengths: 10, 20, 30 or length as needed up to 300 m
  • Protection: IP68
  • Certifications: CE, ATEX (option)
  • Temperature Range: Operating: -20 to 50 °C / Storage: -30 to 60 °C
  • Power Required: Input voltage: 4 to 26 VDC
  • Outputs: 1 passive analog 4-20 mA (velocity only)
  • Communication: RS-485 (serial MODBUS ASCII open protocol) for use with PLCs / RS-485 (proprietary protocol) for use with UNI-TRANS™, IFQ MONITOR™ or RTQ-Logger series / Field interchangeable: Automatic recognition between stationary or portable units
  • Flow Accuracy: ±5% of reading (typical : assumes pipe is 0 to 90% full)
  • Channel Sizes: 0.1 – 10m+ Width, 0.01 – 15m Depth


  • Conversion from surface velocity to average velocity by analyzing surface velocity distribution using a self-learning technology that doesn’t require theoretical modules nor site calibration.


  • Method: Non-Contact Radar Doppler
  • Measurement Range: ±0,15 m/s to ±15 m/s
  • Measurement: Bi-directional
  • Accuracy: ±0,5% of reading ±zero stability
  • Zero Stability: ±0,02 m/s
  • Minimum Velocity: 0,15 m/s


  • Technology: Non-Contact Ultrasonic Pulsed Echo
  • Measurement Range: 0,00 to 1,75 m (with RAV-0002/ULS-02) / 0,00 to 5,75 m (with RAV-0006/ULS-06)
  • Accuracy: ±0,3% of reading (with RAV-0002/ULS-02) / ±0,2% of reading (with RAV-0006/ULS-06) / Includes non-linearity + hysteresis
  • Temp. Error Max.: 0,04 %/K
  • Resolution: 1 mm


  • Method: Non-Contact Pulsed Radar
  • Range: 0,01 to 15 m
  • Accuracy: ±2 mm of reading
  • Resolution: 1 mm


  • Method: Any 4-20 mA loop-powered sensor
Technical data contained in this brochure are subject to change without prior notice, indicative only and not binding.

Sewer/Channel Networks Monitoring

  • Large sewer channels
  • Capacity studies
  • Combined sewer overflow (CSO) studies
  • Inflow and infiltrations studies
  • High velocity flows
  • Discharge

Wastewater Treatment Plants

  • Flow to treatment
  • Discharge
  • Plant effluent
  • Storm discharge
  • Process flow control

Industry & Hydropower

  • Plant effluent
  • Process wastewater
  • Flows with high solid contents, cooling water, industrial compliance monitoring
  • Caustic and corrosive flows

Rivers, Channels & Irrigation

  • Stormwater monitoring and compliance
  • Climate and hydraulic engineering
  • Stormwater basins calculations
  • Permanent measurements of surface water
  • Accurate flow measurement
  • Cost-effective
  • Portable or stationary version available
  • Non-contact: the sensor is positioned above the water surface
  • Easy installation
  • Robust IP68 (PU) enclosure
  • Totally sealed sensor: no joints, seals or screws
  • Developed for field applications
  • Velocity distribution analysis & self-learning technology for average velocity calculation
  • For channels from 100 mm and upwards
  • Easy integration with SCADA, PLC or telemetry systems
  • Perfect solution for difficult flow conditions: high solids content, high temperature, shallow and caustic flows, high velocities and large open channels
  • No maintenance
  • Auto-diagnostic system