DALI Delivers Control and Cost Savings, Headaches Too

Hello DALI. That's what Richard Miller, an electrical engineer with the San Francisco office of HOK thinks about the future of the Digital Addressable Lighting Interface lighting control protocol.

Speaking at the Lightfair International Conference in San Francisco on June 4, Miller presented an overview of the relatively new—and somewhat confusing—lighting control scheme.

DALI sets up rules for lighting control through a computer network, where electronic ballasts are assigned a digital address allowing for control and monitoring.

In a nutshell, Miller believes DALI will eventually be adopted by the industry because it represents a lower cost to building owners, mainly due to a simplified wired scheme.

For example, Miller presented an electrical schematic of a conference room his firm designed. The room, with numerous dimming switches, required five separate circuit branches. With a DALI scheme, only one branch would be required.

DALI advantages also include:

• Building occupants' ability to control their lighting settings from their own PC, which may result in lower energy costs.
• Greater monitoring capabilities for building operators and less maintenance.
• Interoperability, so that the system will work regardless of products installed.

DALI does not have to be employed for an entire building either. For example, it could be used specifically in conference rooms, for which it is particularly suited.

The major drawback to DALI, aside from its being an unknown commodity for most specifiers, and the fact that there is currently a limited source of DALI-related equipment and controls, is that it takes a major commissioning effort—by not only the engineering team, but also the manufacturers, building operators and others.

Specifically, because DALI is a digital code, all ballasts on its chain require an address. The good news is that a computer can randomly spit out these addresses. The bad news, says Miller, is that someone has to physically walk around and log these addresses.

Furthermore, the DALI protocol currently does not address controls, Miller says, which means there will be no guarantee that controls will be able to handle overvoltages due to the protocol's allowance for a combination high and low-voltage wiring.

Despite these pitfalls, Miller sees a bright future for DALI. In fact, he had to update his presentation at the conference after discovering a slew of DALI-related products already being exhibited. Education, he says, will be the key.