Reliable RVR calculation starts with dependable background luminance data at the runway side. ALS-2 measures ambient light for instrumented Runway Visual Range (RVR) systems and is designed to comply with ICAO, WMO and FAA guidance, making it a strong fit for typical aviation RVR installations.
Integration stays straightforward. ALS-2 supports serial outputs (RS232, RS422 or RS485) and can operate standalone or connect directly to a Senseca visibility or present weather sensor, where luminance values are embedded into the host sensor’s data string for a single combined output.
Built for continuous outdoor operation with low maintenance effort, ALS-2 includes a heated window and window contamination monitoring and compensation, plus extensive self-test functions. It measures 0–40,000 cd m-2 with a 6° field of view, operates from -40 °C to +70 °C (down to -60 °C with optional internal heaters), and uses 9–36 Vdc sensor power with optional hood heating.
RVR-ready luminance
Measures 0–40,000 cd m-2 background luminance for instrumented runway visual range systems
Aviation compliance
Designed to comply with ICAO, WMO and FAA specifications and guidelines for RVR use
Easy system integration
RS232/RS422/RS485 outputs, and can embed data into Senseca visibility/PW sensor strings
Low maintenance design
Heated window plus contamination monitoring/compensation and extensive self-test functions
Features
Luminance measurement
Measures ambient light (background luminance) in cd m-2, averaged over a 60 s period with 1 cd m-2 resolution
Optical characteristics
Uses a 6° field of view and spectral response from 420–675 nm with peak at 565 nm, analogous to CIE luminous efficiency
Digital communication
Provides serial data via RS232C or optional RS422/RS485, with user-selectable baud rates and selectable checksum
Analog outputs option
Optional dual 0–10 V outputs provide low mode (0–4,000 cd m-2) and high mode (0–40,000 cd m-2) scaling
Heating and contamination handling
Window heater is fitted as standard; window contamination monitoring and compensation is fitted as standard; optional hood and internal heaters are available
Installation and alignment
Pole-mount bracket fits 40–64 mm OD poles and allows elevation adjustment from 0° to 45° with alignment guides
Operating environment
Operates at 0–100% RH and -40 °C to +70 °C (to -60 °C with optional internal heaters), with IP66-rated enclosure
Power and outputs wiring
Uses 9–36 Vdc for sensor and window heater, with optional 24–28 Vac/dc supply for hood and internal heaters
