More often than not, if you ask a lighting designer or engineer what DALI is and if they specify it, you’ll get a puzzled look or a chuckle. Some designers are dipping their toes in the pond, but most are waiting to see what the other guys are doing, not wanting to be the first for fear of getting burned on an unproven technology. The truth is, however, that while the U.S. has been plodding along with good old switching relays, 0-10V, and line-voltage dimming, the European design community has already taken lighting control into the digital age and embraced DALI as the preeminent, universal lighting control language.
While those traditional technologies are tried and true, complacency does not constitute a reason to ignore a proven system which has the potential to save time, money, and energy, while increasing beneficial functionality. Here are a few points that examine why DALI has potential and why we aren’t using it enough.
First though, we need to know what exactly DALI is. DALI (not Salvador Dalí) stands for “Digital Addressable Lighting Interface”, and is basically the computer language that devices send and respond to, kind of like Morse code for lighting. The DALI control signals are transmitted over two low-voltage wires that connect to each DALI ballast or relay, each of which has a unique address. Control commands are sent out over the wires to tell individual devices or groups of devices to turn on and off, dim up and down, etc. The devices even have the ability to report back to the controller indicating a lamp failure or how much power they are using. This kind of send-and-receive communication is analogous to a teacher (controller) and classroom full of students (ballasts and relays). The teacher gives instructions to the students (which they obediently obey), and each can answer questions when called on.
What does DALI have that your current controls systems don’t have?
DALI systems can use up to 60% less branch wiring than traditional controls
That’s a strong assertion, but if you lay out the wiring for a traditional system and measure it, for any typical room you would see that by the time those switch legs go down and back up the wall and then out to each controlled zone you have quite a bit of wire. Don’t forget to consider the conduit – lots of metal! Now, if you lay out the same space with a DALI system, you simply don’t have all those switch legs to contend with. The branch circuit flies into the room from the adjacent space, hits each light fixture or addressable relay, and continues on to the next room. All switching and dimming is done in the ceiling at each fixture, not in a wallbox or remote cabinet. While there is some control wiring that connects all the controlled fixtures into a loop, that wiring can be Class 2, run without conduit, (or Class 1 that runs in the same conduit – still cost less than switch legs) and results in much less material, labor, and cost.
DALI is based on an open protocol
Using an open protocol means that anyone can develop their own DALI devices, ballasts, relays, sensors, etc. The programming language is freely available to anyone that wants it.
That also means that it has the potential to be a universal language for the lighting industry (as has happened already in the EU), so Brand X DALI light fixtures will work with Brand Y DALI control systems. You don’t need to worry about compatibility and which type of dimmer to use anymore.
DALI is easy to specify
Whether the lighting designer or engineer does it, someone has to figure out which traditional dimming ballast or transformer to use with which traditional dimmer. With DALI, it’s simply DALI – DALI ballasts with DALI controllers. Most of the major ballast and gear manufacturers have DALI ballasts already available, and their product offerings continue to expand. Even better, most ballasts, DALI or otherwise, are now universal voltage – you don’t even need to coordinate that!
The proliferation of DALI will also allow for three-name ballast specifications again, unlike the forced specification of a proprietary technology caused by no two systems being alike.
DALI is easy to install
A light fixture gets power (120 or 277 volts – it doesn’t matter as far as the control is concerned) and control wires – that’s it. The rest is in the programming. The control wires are polarity-free, so it’s virtually impossible to wire a fixture incorrectly, unless you forget to. Once contractors understand how easy the installation really is, and they get past the “new technology” hesitation, they should be jumping for such an easy system. Some already have.
So why hasn’t the U.S. embraced this technology yet? Some of the reasons are more complex than others, but there are many possibilities:
Lack of specifier demand
This is simply a chicken-or-the-egg question. If specifiers don’t know about it or don’t understand it, how would they know to ask for it?
The perceived complexity of digital communication and control is something that might be hard for specifiers to wrap their heads around. It’s certainly a lot different from switching and dimming line voltage we’ve been using for the past 40 years. Since there are few manufacturers with front end systems, thus far, education has been lax.
For the same reason that specifiers are hesitant to specify it before the competition weathers the “new technology” first, manufacturers are wary of investing in the development of a new system that is so different from what they already offer. They want someone else to do it first to see if it takes off or flops.
There are a few manufacturers that have come up with quasi-digitally-based systems but they’re mostly proprietary, operate in different ways (i.e. cannot be listed as equals), and usually end up converting a digital signal to analog. Unless these systems permeate throughout the industry, their fate will be to persist as a minority, or they will cease to exist.
Sometimes DALI is even discredited as “slow”, “old”, and “expensive”, rejected for specific business interests and investments in competing technologies. A lot of time and money has gone into developing all those other control systems, and to simply adopt DALI, the universal open protocol, would almost certainly cut into profit margins. This may be the single biggest hesitation factor in the U.S.
So what’s next for DALI? Will it ever fully take off in the U.S.? There certainly is vast potential for any manufacturer that wants to take up the technology. It makes sense from so many angles, and if we could just get everyone to agree to adopt it we’d really have something, but that’s a bit like herding cats – good luck!
Photos credit: Matt Latchford / Lam Partners Inc