DALI (STANDARD), not Dalí, stands for Digital Addressable Lighting Interface. When LEDs were first introduced, 0-10v dimming and phase dimming were the main options for dimming these sources. LEDs are a digital technology. As digital lighting started to become more and more commonplace, the lighting industry needed to start looking for other control options. ESTA/USITT DMX512 (STANDARD), or Digital Multiplex with (512) pieces of information, existed mainly in the entertainment industry, but that kind of control is quite robust compared to that of 0-10v or phase dimming. DMX also supported color chaning and had a tendance to reduce flicker and cause deeper dimming of LEDs. But the cost of a DMX system including cables, opt-splitters, and the controllers can be cost prohibitive.
Thus, DALI, simplifying the way we approach digital controls as well as architectural lighting. While majority of the world has caught up to primarily using the DALI, the United States and North America market is still working on making it the industry standard. So, what exactly is DALI?
To keep it simple, DALI is a digital control network that contains at least one controller, or brain, with a power supply in order to send and receive and communication to a driver. Drivers are what is associated with the LED, regulating the electrical power for dimming. What is great about the DALI bus is it provides data, or control information, to the necessary equipment, only requiring (2) cables for wiring just like 0-10v, only with DALI the polarity does not matter. In addition if using DALI compared to 0-10v is that these (2) wires are a bi-directional in information exchange. When fixtures have any issues or problems, that can be shared with the controller in order to let the user know what needs resolved and where they can find the fixture outage. Knowing the basics of a DALI works, let’s look at how a normal system might be setup.
DALI networks can handle up to (64) control gear and (64) control devices maximum on a basic system. The addressing on this network would be from (0) to (63). We normally suggest using no more than (55) control gear on a system in order to give the installer room for any additional gear that might get added for future installations. Most projects using DALI will be made up of several systems to make a larger DALI network. When it comes to actually controlling the lighting fixtures, DALI has (254) steps of intesity change where (0) means off, (1) is 0.1% brightness, (254) is 100% brightness, and everything in between uses a logarithmic interpolation to create a subtle curve as the intensity rises or falls. When set to (255), the light will freeze and not change in intensity. This could be used to stop a fade or some type of dynamic look. Devices are able to store (16) programmable scenes or looks for a room, with an additional 17th scene saved for emergency settings if control connection is lost. DALI also has evolved into a few different forms. DALI-2 is the current edition for of basic controls, having updated the original DALI protocol. DALI Type 6 and DALI Type 8 are two different ways you can approach controlling a fixture on a driver. DALI Type 6 has a Single-Channel and Multi-Channel way of using the alotted 64 addresses, 55 is Morlights standard. Single-Channel uses (1) address to control (1) channel. An example for this will be color temperature being on one channel, and brightness on a different channel. Multi-Channel has a similar approach where you can use certain amount of adresses to control and equal amount of channels. An example would be using (3) addresses to control (3) channels for a fixture. Lastly, DALI Type 8 is able to use (1) address to control (2) channels. So using the first example, one could use (1) address to control both color temperature and brightness on a fixture. Because DALI Type 8 needs more to process, it is a little more expensive than DALI Type 6. So, it all comes down to cost and neccessity of the project when deciding on which to use. After diving deep into the specifics, now let’s talk about why we suggest using DALI.
As stated before, DALI uses (2) control wires similar to 0-10v systems. But, that is all that is needed for the DALI fixture. 0-10v requires more wiring for power relays and emergency lighting, costing more for wiring. 0-10v requires polarity and topology to function a certain way, where DALI does not require either to function. Each set of like fixtures, also called zones, must stay with in the same wiring chain for 0-10v. DALI is digital, so zones can be assigned electronically. All of these limits in 0-10v create flicking in LEDs, where DALI has been able to manage the dimming of LEDs negating any form of flicker. DALI is the ideal way to control digitally going forward in the architectural lighting industry.
Hopefully this brief break down of DALI helps you understand our position of specifying this type of controls. If you would like any further specifics pertaining to DALI, this publication from IEC gives a complete breakdown of DALI: