DALI: The Next Breakthrough in Lighting?

Daylight and occupancy sensors can be directly connected to lighting bus Benefits of digital lighting networks include:Energy savings. Digital ballasts can be dimmed or switched either on a scheduled basis according to time of day (such as during peak demand periods) or in response to variable conditions such as quantity of available daylight. “As energy costs continue to rise, intelligent use of available daylight and increased monitoring of lighting system usage will be key to avoid wasting energy,” says Paul Ratliff, product marketing manager at OSRAM SYLVANIA’s Electronic Control Systems division. “DALI protocol provides the basis for smarter, more cost-effective lighting systems.”Worker satisfaction. A study completed by the Light Right Consortium found that occupants are more satisfied and motivated when they are able to set light levels to their own preferences; a recent Watt Stopper-funded study found that a significant portion of the market would pay a premium for this capability.Flexibility. The lights can be dimmed to tune light levels to changing space needs, without the need for rewiring, a significant advantage over 0-10V analog dimming systems.“DALI will provide greater flexibility and eliminate the need for rewiring if building layouts change,” says Stuart Berjansky, dimming product manager for Advance Transformer Co.Maintenance. The central computer can collect information from the ballasts as well as transmit it, turning the central point of control into a monitoring station that recognizes anomalies (such as lamp failures) and signals a maintenance need via alarms.Demand for digital lighting networks is currently inhibited by several factors, including:Compatibility. To set up a working digital lighting network, all lighting controls connected to the network must be DALI-compatible.“Development and introduction of DALI ballasts and controls have been slow in Europe and North America,” says Berjansky of Advance. “The key issue is the limited availability of DALI-compatible controls, which are a critical component of the system.” Complexity. Digital lighting networks are more sophisticated than traditional lighting systems in regards to set-up, programming and commissioning. As a result, like building automation systems, they are generally best suited for large installations.“The development of digital lighting networks has been slow in coming due to the complexity of the system, which requires matched components together with initial commissioning issues,” says A.J. Glaser, president of HUNT Dimming. “Once it is fully realized, building owners will enjoy greatly enhanced control over their environment, both today and in the future due to the built-in flexibility of the system.”