RWS-30 Road Tunnel Weather Sensor

Model Number: RWS-30
Manufacturer: Biral
Product Brochure: Download

The RWS-30 Road Tunnel Weather Sensor is designed for use in road and tunnel applications where accurate and reliable visibility measurements are required.

Overview

RWS-30 Road Tunnel Weather Sensor

The RWS-30 Road Tunnel Weather Sensor is designed for use in road and tunnel applications where accurate and reliable visibility measurements are required. The forward scatter measurement principle provides a compact design with measurements that are both accurate and reliable in all weather conditions. The RWS-30 outputs have been chosen to match those recommended for use in tunnel systems.

  • 200m to 99.99km measurement range
  • Compact forward scatter design
  • Not affected by lights
  • Easily installed by one person
  • Window heating and contamination monitoring
  • EXCO and MOR Outputs
  • Analogue voltage and current outputs
  • Serial data output (RS232, RS422 or RS485)
  • 2 Years warranty

Technical Description

The RWS uses a 45° forward scatter angle and 850nm infrared light source to provide a flexible, cost effective, visibility solution specifically tailored to road weather applications. Visibility is output as both Meteorological Optical Range (MOR) and Extinction Coefficient (EXCO) to provide compatibility with the widest range of control systems.

In common with all Biral visibility and present weather sensors, the RWS-30 uses our established, reliable, 2kHz modulation of the light source, combined with narrow pass band optical filters and synchronous detection at the receiver. This established technique ensures the measurement is not affected by bright or intermittent (flashing) lights, and is optimised for road usage. This unique design also ensures the sensor accurately reports visibility during precipitation. The horizontal hood design eliminates surface reflections problems that are a source of error in sensors employing look down hood geometries.

The sensor hoods can be fitted with optional hood heaters to ensure blowing snow does not block the optical path. The hood heaters have their own supply connection, allowing the use of unregulated supplies which can help to reduce infrastructure costs. The hood heating only operates when the temperature drops below 2°C and can be disabled through the sensor interface if required.

The optical windows of the sensor are fitted with low power heaters to prevent the formation of condensation. Window contamination monitoring and compensation allows the visibility output to maintain its accuracy even as dirt builds up on the optical surfaces. The sensor reports the window contamination in the output message, using two stages of warning flags to allow cleaning to take place in a convenient manner.

Communication with the sensor is over a serial data link that is user configurable for RS232, RS422 or RS485. ASCII encoded data is used and the sensor can operate in either a polled or broadcast modes. The sensor’s standard analogue voltage and optional current outputs can be configured to report either MOR or EXCO. The sensor also has the option of being supplied with two threshold relays and one fault relay. The threshold relays can be configured by the user as either two user defined visibility thresholds relays, or one visibility threshold relay and one window contamination alert relay.

The sensor operates from a low voltage (9V to 36V) DC supply and requires just 3.5W. The low power window heaters which can be set to only operate when condensation is detected take an additional 1.7W (5.2W total). The optional high power hood heaters have a separate power connection allowing the use of an unregulated heating supply.

The RWS-30 is a single lightweight unit that can be easily installed by one person. The sensor enclosure is constructed from aluminium which is surface passivated and finished with a grey powder coat paint. It is designed for use in all types of weather and has a wide operating temperature.

Specifications

Measurement Visibility (MOR & ESCO)
Output RS232, RS422 or RS485
0-10V
4-20mA and relay outputs
Measurement principle Forward scatter meter with 39° to 51° angle, centred at 45°
Measurement error ≤10.0% at 200m to 10,000m
≤20.0% at 10,001m to 30,000m
Sensor power 9-36Vdc
Window contamination monitoring Fitted as standard to both sensor head windows
Operating temperature -40°C to +60°C
Operating humidity 0-100% RH
Protection rating IP66/IP67
Weight 4.3kg
Colour Grey - RAL 7045

Sales & Support

Contact Biral for more information

To find out more about this instrument or to discuss your application requirements please do not hesitate to contact Biral.

  • email enquiries@biral.com (or use the Request More Information button below the product photograph)
  • Telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

After Sales Support

Biral offers free advice and technical support for the lifetime of the instruments we sell. Once you have purchased the unit you can always contact us for help using the links on our Technical Support page.

Accessories

  • SWS Calibration Kit

    Model Number: SWS.CAL

    The SWS Calibration Kit allows the calibration of all current SWS visibility and present weather sensors to be checked and …

    Read more >