ABB TWA-1 and TWA-2 switches

ABB’s TWA astronomical twilight switches automatically control lighting circuits depending upon the time of sunrise and sunset, without requiring the use of an external daylight sensor.

The TWA-1 and TWA-2 switches are said to provide energy savings of more than 30% due to the automatic control of lighting and other loads. They provide a suitable solution where the use of external sensors could be a problem.

The installation of an astronomical twilight switch in a system is a particularly useful addition for situations where light sources, or other environmental conditions, can cause changes in the brightness level and allow false readings and inaccuracy of traditional sensors. In these cases, the TWA-1 and TWA-2 astronomical switches can control the lighting system by internally calculating the sunrise and sunset times of the geographic zone where the system is installed. This is suitable in situations where high pollution environments can affect traditional sensors, or areas where vandalism of external sensors is seen to be a problem.

The installation of the TWA-1 and TWA-2 astronomical twilight switches is particularly suitable for applications where the operation of a traditional twilight switch with external probe can be falsified or compromised by an external cause (such as environmental pollution, overexposure to light, vandalism etc.).