FG-8 Tunnel Entrance Photometer

Veiling glare photometer is designed for measuring Lseq veiling luminance and regulating tunnel illumination in accordance with the advanced approach of the CIE 88:2004 standard. The standard defines the simulated driver’s view field as the sum of individual angular sections contributing to the overall light perceived by the driver. The FG-8 photometer measures light in those sections and calculates Lseq veiling luminance. This data predicts the most realistic lighting conditions a driver would experience when approaching the tunnel and serves as the basis for light regulation in the tunnel’s threshold cone. By eliminating the “Black Hole” or overlighting effect, the FG-8 photometer ensures precise tunnel illumination and maximum visibility while saving energy.

The photometer includes analog U/I/f outputs, RS232/485 serial ports for PLC and tunnel SCADA connection, and multiple 230 VAC outputs. These can control lighting contactors directly or be individually programmed for pulsed power-line luminaire control. The design allows for continuous light adjustment throughout the tunnel. All features—including measurement range, light threshold switching, and time averaging—are PC programmable using the provided software.

The photometer is available with various X-Y adjustable wall or pole brackets. The compact stainless steel housing is built for extreme environmental conditions. An embedded anti-fog heater and a sensor chamber stabilized to within 1° ensure high-accuracy readings and negligible aging. Wiper-washer units and water tank are available.

Fields of Use

• Traffic areas

• Tunnel entrance photometer

• CIE 88:2004-compliant measurements