What Is DALI?
DALI is an addressable communications protocol. DALI stands for Digital Addressable Lighting Interface and is part of IEC 60929 Annex E. DALI originally appeared in the market place in the mid 1990s and has been used, up until 2009, in relation to dimming applications. The DALI standard has been updated and now covers emergency lighting, allowing for a fully addressable emergency lighting system running along side the dimming system on the same control system.
Advantages Of DALI
DALI has many advantages over other control protocols as it has been accepted by all the major ballast manufacturers, this means that any DALI ballast will work correctly with any control system.
- Simple wiring of control lines (no group wiring, polarity free)
- Wiring does not have to be segregated from the mains supply cables
- Light sources can be switched on and off from the control wiring
- Control of individual units (individual addressing) or groups (group addressing) is possible
- Simultaneous control of all units at any time through broadcast controls
- Flexible after installation, if areas change, no physical re-wiring is needed
- No interference of data communication due to simple data structure
- Device status, lamp fault, current level, assigned group, battery status feedback
- Automatic search and discovery of devices
DALI has very few disadvantages due to the protocol being defined as an industry standard.
- Limited to 64 devices per single network
- Limited to 250mA per single network
- Maximum fade rate of 90 seconds
- Only controls from a single manufacturer can be used on any one system
DALI systems can comprise of small systems covering a single classroom up to large configurations running up to thousands of fittings in more than one building. DALI systems can facilitate a truely scalable solution.
At Apollo Lighting we can compile a DALI control package to suit your own application and provide guidance on the most suitable solution. We have supplied many DALI systems from one room up to large scale building projects. See our Case Studies section for a selection of highlighted projects implementing a variety of systems.
The DALI network cable does not have to be a special cable. We recommend a Belden 8471, which is a mains rated, 2 core, 1.5mm² flex. The maximum cable length using this cable is 300m, which equates to a 2V drop. An equivalent to the Belden 8471 can be used but it must be mains rated.
The only stipulation in wiring is that the DALI cable is not run in a complete ring. 'Star' or 'radial' topologies are acceptable. The DALI cable is not polarity sensitive. As long as all the DALI devices have a connection to the network, they will function as designed.
Each DALI component on a network requires a certain current to operate, for instance, a ballast requires 2mA. Detectors and switches require more power. The technical information on each product shows the power required for each unit.