Editing Digital Addressable Lighting Interface (section)

==Device addressing==
A DALI device, such as a LED driver, can be controlled individually via its short address. Additionally, each DALI device may be members of one to 16 groups, or be a member of up to 16 scenes.  All devices of a group respond to the commands addressed to the group. For example, a room with 4 ballasts can be changed from off to on in three common ways:

===Single device===
Using the Short Address, e.g. sending the following DALI messages:

* DALI Short Address 1 go to 100%
* DALI Short Address 2 go to 100%
* DALI Short Address 3 go to 100%
* DALI Short Address 4 go to 100%

This method has the advantage of not requiring programming of group and scene information for each ballast. The fade time of the transition can be chosen on the fly.
If a large number of devices need to change at once, note that only 40 commands per second are possible - therefore, 64 individual addresses would require 1.5 seconds. For example, turning all lighting fixtures off may result in a visible delay between the first and last ballasts switching off. This issue is normally not a problem in rooms with a smaller number of ballasts.  Groups and Scenes solve that.

===Device groups===
Using the DALI Group previously assigned to ballasts in the room, if Short Address 1, 2, 3 and 4 are members of Group 1, e.g.: 
* DALI Group address 1 go to 100%

This method has the advantage of being immune to synchronization effects as described above.
This method has the disadvantage of requiring each ballast to be programmed once, by a DALI master, with the required group numbers and scene information. The fade time can still be configured on the fly, if required.

===Broadcast===
Using the DALI Broadcast command, all control gear will change to that level, e.g.:
* DALI Broadcast go to 50%