Tunnel photometers & PLC

Model TLS-420 (Incl. TLS-420/S & TLS-420/SW)

The Hagner TLS-420 Tunnel Entrance Photometer is designed to measure the average luminance of road tunnel entrance and its surroundings according to CIE recommendations and is used, together with a PLC/computer, to regulate the lighting inside the tunnel. The idea is to control the illumination inside the tunnel to a level corresponding to the degree of light adaptation of an approaching cardriver´s eyes.

Tunnel Photometer Accessories

Information about accessories, such as Washer Unit and Mounts

Model OVP-02

The Hagner OVP-02 Overvoltage Protection has been designed to give extra protection to the Hagner TLS-420 Tunnel Photometers which are mounted in areas where there are risks from over voltage and/or transients, caused by an unstable power supply or lightning strikes in the surroundings.

Model EH-150

The Hitachi EH-150 PLC computer has been provided with a specially designed program for regulating road tunnel lighting. The PLC receives a 4-20 mA signal from a Hagner TLS-420 Tunnel Photometer (where 4 mA = 0 cd/m² and 20 mA = the chosen calibration level, e.g. 6,500 cd/m²). The PLC has been programmed to activate built-in relay switches at certain current levels (up to 10 levels set according to the customer\'s requirements). Programmed time delays mean that a switch is only activated when the signal has been steady over or under the level in question for a certain time. The relay switches can then be connected to contactors which regulate the lighting inside the tunnel. The preset switching levels and time delays can easily be changed by the customer by means of a Display Unit, which normally is ordered with the PLC. Each PLC can in standard version be used with 2 separate Tunnel Photometers.

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