Dimming of fluorescent lighting offers significant benefits - giving users control of their own lighting, and realising energy savings. In certain environments it is a must, for instance in a lecture theatre to modify the lighting level when beaming a presentation. In other applications the flexibility it gives to people has significant value, allowing them to match the illuminance level on the working plane to their personal needs.
The control systems surrounding dimming of fluorescent lamps are becoming increasingly complex, for instance when linked to a daylight harvesting system to provide artificial lighting only at times of reduced natural illumination. Dimming creates a rich visual experience and adds flexibility to any room, providing the right lighting environment for a variety of activities.
An added bonus is the fact that modern electronic ballasts permit a reduction in power consumption in parallel with the reduced light level, and this presents a valuable energy saving opportunity. A further advantage is the use of dimming as an alternative to repeated on/off switching. In this fashion substantial energy savings can be realised but without negatively impacting lamp life.
Dimming of fluorescent lamps is accomplished today using special high frequency electronic ballasts. By providing a variable signal voltage to the ballast, generally over the range 1 to 10 Volts, it can be triggered to regulate lamp power. Standard lamp types can be used in all cases, and there is no further need to specify the former metal striped tubes when using modern HF ballasts. Several protocols have emerged concerning the method of communication between a user interface and the dimmable ballast. The most common of these are DALI (Digital Addressable Lighting Interface) and DMX-512 (Digital Multiplex 512 channel). The precise choice of hardware often varies somewhat between different manufacturers, who should be consulted directly for detailed advice.
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