Fully featured ambient light sensor for Runway Visual Range (RVR) applications.
The Background Luminance Sensor LM21 is a precision photometer with a verified photopic spectral response. It measures the total amount of light coming in from an angle of 6 degrees to assess the visibility range of runway lights or warning lights.
The LM21 features:
It integrates with the Vaisala Transmissometer LT31 and Vaisala Forward Scatter FD70, FS11, or FS11P to create an expanded runway visual range (RVR) system.
To ensure reliable and uninterrupted operation, the LM21 has extensive self-monitoring functions and high-power heating features built into its design.
Optical path clearance monitoring circuitry verifies measurements are not affected by obstructions. Attenuation compensation for window contamination ensures measurement accuracy between window cleanings, and also extends the cleaning interval.
The calibration of LM21 is traceable to international measurement standards for luminous intensity. The calibration coefficients for light intensity have been defined during factory calibration and stored in the LM21 memory.
Quick field calibration can be done using a unique field calibration device (LMA21) that provides a stabilized and diffused white light beam for LM21 calibration. Calibration starts automatically when the calibration unit is connected.
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Contact Vaisala to learn how this stand-alone ambient light sensor can deliver crucial data while helping simplify your Runway Visual Range (RVR) system.
Discover the power of stand-alone ambient light sensors to improve runway illumination monitoring.
The industry's most accurate runway visibility data.
A comprehensive, hands-on training course for the Vaisala LT31 and LM21 operation and maintenance. This in-depth four-day course gives you practical training on how to operate, maintain, and troubleshoot LT31 and LM21.