SWS-200 Visibility & Present Weather Sensor
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Bfral Visibly Better SWS-200 Visibility & Present Weather Sensor Datasheet forward scatte Visibility measurement using established )rincipies for compact design and extended measurement range Present weather monitoring using exclusive backscatter sensor gives unparalleled ability to identify VI ■ frozen precipitation Wide range of applications from aviation to road weather and national weather service networks KEY FEATURES & BENEFITS 9 Selectable measurement range from 10m to 75km • Selectable measurement resolution of lm or 10m (default) 9 WMO 4680 present weather codes • Compact forward scatter design I Window contamination monitoring and compensation 9 Direct connection of the ALS-2 Ambient Light Sensor for use in Runway Visual Range (RVR) applications • Digital, analogue and switching relay outputs • Comprehensive self-test and maintenance data • 3 Years warranty The SWS-200 is the sensor of choice where extended visibility range measurement combined with reliable present weather identification in a compact package is required. The use of a backscatter receiver, exclusive to Biral, significantly improves the accuracy of present weather reports especially when distinguishing frozen from liquid precipitation. The SWS-200 is easily integrated into monitoring and logging systems using the serial communication interface whilst analogue output options and alarm relays can be used for legacy systems and activation of local warnings. Visibility & Present Weather Measurement The measurement of visibility by forward scatter as used by the SWS-200 is now widely accepted and seen as having significant advantages over more traditional techniques such as the use of transmissometers or backscatter sensors. Backscatter sensors share the SWS-200's advantage of being compact however, the backscatter signal is strongly dependent on the type of obstruction to vision resulting in poor accuracy and limited upper range. Transmissometers were once considered the standard method of visibility measurement due to their direct measurement of visibility. However, their limited measurement range, high cost of acquisition, large size and significant maintenance costs have resulted in their use being limited to a few specialist applications. The SWS-200 by contrast is compact, requires little maintenance and has a visibility range of 10m to 75km, with a user selectable measurement resolution of either 1 or 10m. Its performance is proven to be comparable to that of a transmissometer. The calibration of the SWS sensor family was undertaken in accordance with the recommendations of ICAO 9328 and is traceable to a national weather service transmissometer.

Forward scatter sensors are able to determine precipitation type by observing the intensity of scattered light and the transit time for each precipitation particle as it passes through the sample volume. These parameters are used to estimate the particle size and determine if it is liquid or frozen using well established relationships, unfortunately in anything other than still conditions the relationships become unreliable, resulting in poor classification accuracy. Biral sensors are the only ones to solve this problem through the use of a backscatter receiver. The ratio of forward to...

Sensor Configuration Information For a detailed explanation of the configuration options please refer to the table below. SWS-200 Sensor Housing: 20 - Powder paint coated aluminium (standard) 20A - Hard coat anodized, powder coated Hood Heating: HV - With heating NH - Without heating Data Output: J - Standard outputs K - 0-20 mA as well as standard output L - 4-20 mA as well as standard output Self-Test and Monitoring: S - Standard self-test and monitoring A - Advanced self-test and monitoring Cable Glands: PG - Standard plastic cable glands MG - Single metal cable glands Ambient Light...

Visibility & Present Weather Measurement Additional Features Hood heaters Operating temperature Certification & Compliance_ CE Certified EMC compliance with EN61326-1997, 1998, 2001 RoHS and WEEE compliant Output rate (seconds) Power Requirements Sensor Power Self-test capability Included with Sensor The sensor is delivered in sturdy recyclable foam filled packaging with: - Pole mounting kit (2 x U-bolt) - User manual and calibration certificates Accessories - Optional Specifications are subject to review and change without notice. E&OE. © Biral - Bristol Industrial & Research Associates...