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System Guidelines
Functional compatibility
Compatibility of ballasts is guaranteed by the standard. For other units, like sensors and controllers the compatibility ensurance is in process and the and a standardization will be achieved. Compatibility has always to be ensured when a system is being designed.
System size
The maximum number of individual addresses available in the DALI standard is 64. The maximum DALI supply current is stated as 250mA maximum.
Maximum ballasts in a system
Up to 64 individual ballasts can be connected in a DALI line without exceeding the system node or power supply current limits. This, of course, does not allow for any DALI control devices to be connected to the system.
Ballasts and control units in a system
If control units using the DALI protocol are to be used in a system then the system size will be limited to either 64 nodes or 250mA total system current (whichever value is reached first). When a DALI system is to be constructed containing both ballasts and control units it should be ensured that these limits are not exceeded. If the system size exceeds the limitations there will be problems due to reduced signal integrity ? some devices may fail to communicate or respond to commands and the system operation will become unstable.
Routing
The maximum voltage drop on the DALI line may not exceed 2V, resulting in a maximum line length of 300 m, between the DALI components furthest apart.
Good practice
For the above mentioned reasons it is the task of the system planner to consider the power consumption of each component used and to plan the system in such a way that the system limitations are not exceeded. |