ALM (Ambient Light Monitor)

SSL designs and manufactures a number of variants of the ALM ranging from a single sensor used in Techspan message signs to the dual sensor ALM used in the MS3 and MS4 message signs.

The ALM monitors the average light readings taken from the sensors over a 3 minute period to ensure that sudden changes in ambient lighting conditions do not adversely affect the ALM output.

SSL have customized a successful basic design to meet a number of specific customer requirements. These include a variation of connector types in addition to signaling modes and software.

Optical Head Sensor ALM4 – the above image shows
a “Z” Bracket mounting attached to the top of a motorway
gantry.