ILLIOS Tunnel Illuminance Photometer

Designed specifically for the tunnel environment, the ILLIOS measures the level of illuminance within the tunnel bore to ensure interior illumination levels are being continuously maintained in order to ensure safe lighting conditions for drivers. Illuminance, or incident lighting, determines the amount of light that covers a specific surface or area within the tunnel.

The ILLIOS uses a specially designed, highly light-sensitive photocell to continuously measure cosine corrected planar illuminance within the tunnel thus allowing elimination of directional error. The measurements are converted into an output signal of 4-20 mA (directly proportional to the illuminance measurement) for hard wire connection and signal transmission to a host controller.