DALI Broadband versus DALI Addressable
Why use DALI at all, why not use mains dimming or 1-10V. If we ignore the pros and cons of the DALI wiring format and look at protocol vs protocol then it is all about the application and type of light being used.
DALI Addressable Drivers are being widely specified predominately to provide the ultimate in flexibility. (up to 64 drivers on one twin 1.5mm loop that can be split into a maximum of 16 separate circuits)
Additionally the DALI “standard” states the performance objectives of a driver; so if you want to dim a linear LED strip or downlight to 1% of light level (or lower depending on the driver) then you can do it and the DALI standard guarantees that performance. Mains and 1-10V dimmable fittings do not have such standards and therefore can be harder to control effectively.
Furthermore the wiring is totally straight forward. However careful attention is required when developing a lighting scheme for DALI controlled fittings as to whether a DALI Addressable (grouped for control in programming) or DALI Broadcast (wired together in groups) should be adopted.
Addressable DALI control allows up to 64 devices to be linked together and controlled individually or in groups which are defined during programming but importantly can always be changed. This simplifies the wiring requirements and is ideal for applications where the final design has not been confirmed i.e. in a commercial office space where walls may not have been constructed or where the layout and design will change regularly i.e. short-term leased space or dare I mention, the client changes their mind!
Addressable control is also very useful where the cabling needs to be kept to a minimum due to installation restrictions i.e. for exterior light fittings and heritage buildings where the cabling and routing will be expensive and restrictive.
Addressable DALI allows feedback from the fittings on their operational status and consequently widely used for full Emergency Lighting Control applications.
DALI Broadcast control is where all the fittings on a DALI control line are controlled together with no individual addressing capabilities. This can be very useful where the lighting design has already been decided, especially using linear where all the LED’s need to be controlled together. While this results in more control cabling, the power cabling can remain the same and there is no timely addressing of the fittings.
The programmability of DALI can become a cost issue rather than a benefit i.e. if a number of fittings are always going to operate together then wiring them together as a separately controlled circuit reduces the cost of programming them all individually.
Some Addressable DALI Systems claim a “self-healing” operation where a fitting can be replaced without reprogramming but this assumes that only a single fitting has failed which is not always the case and then leads to more complicated programming. With the Mode web browser control it is relatively simple to recommission fittings but it does require a level of maintenance support.
Using DALI Broadcast gives you the ability to add or change fittings on a control circuit without needing to program them, resulting in lower maintenance costs.
As a separate note, some features are best dealt with by DALI Broadcast – RGBW and Colour tuning are handled in the control modules without programming of the fittings which dramatically reduces setup time.
Where different protocols are being used i.e. mains dimming, DMX etc then separating the DALI control to broadcast channels can help in terms of treating each control channel as a separate circuit with separate wiring that becomes much easier to wire.
When to use Addressable DALI
When the final operational requirements of a system are unknown
Where there are wiring restrictions (exterior / heritage buildings)
Where in-field System Expansion will definitely be required (eg phased projects)
Where DALI is the only protocol in use
Where the number of fittings being used is limited
Where ALL fittings will be installed prior to commissioning
Where feedback is required to a BMS or Emergency Test system
Where the cost of commissioning of fittings can be justified due to the above points
When to use Broadcast DALI
When the final operational requirements of a system are known and therefore the addressable nature is not of benefit
Where multiple protocols are being used and individual circuit wiring is clearer to all
Where the building layout makes it labour intensive to identify fittings in multiple rooms
Where feedback from fittings is not required
Where a large number of fittings need to be controlled together
Where fittings may be installed in stages or not all the fittings on a circuit are connected
Where the cost of commissioning of DALI fixtures does not justify the flexibility of DALI Addressable control
DALI Lighting Costs
The UBC (addressable module) controls a maximum of 64 fittings split into a maximum of 16 circuits and costs £396.00 with a couple of hours programming.
The DBM (broadcast module) controls 8 circuits, with a maximum of 30 drivers per circuit and costs £495.00 with 30 minutes programming.
The Mode eDin Dimming system will make it work which ever way you require …