Category Archives: Smart Home

Difference between D-Bus and DALI

The differences between the D-Bus and DALI lighting control systems.

A. The DALI lighting control system

DALI is a lighting control system with a single luminaire as the basic unit of control, in a single distinct zone there can be up to 64 luminaires. An address is assigned to each ballast or LED power of the luminaire, which is matched with a preset digital switch to form a lighting control system. The unique features and limitations of such a system are as follows:

  1. Within the system, there is only a maximum of 64 possible addresses, each luminaire will occupy one address, and thus it is suitable only for small to medium sized venues and is not suited to large scale venues or buildings that has more than 64 luminaires.
  2. When the address needs to be set or when the groups or patterns needs to be configured, a computer installed with special configuration software needs to be used, and the process is very technical and complicated, and it cannot designate what luminaire will use what address.
  3. In a DALI system, each component takes up one of the 64 possible address, and this includes the digital switch as well; thus, the more digital switches there are in a system, the less luminaires can be included.
  4. The power supply used for control in a DALI system is not just any ordinary power supply, it is the system power supply and thus there is a great restriction on the possible wiring distances (which is just enough for a small system with a maximum of just 64 components)
  5. Every system requires a DALI main control unit. If for any reason the main control unit fails, then the entire system dependent on it will also fail. There is absolutely no backup; the safety is dismal.
  6. Every one of the lighting fixture in a DALI system must be DALI branded, and thus any lighting fixture that is not DALI cannot be part of the DALI system. The possible selection of lighting fixtures is thus limited in many ways.
  7. There is no way to make use of different types of sensors, as for example infrared or lux sensors.
  8. If any power supply or ballast fails, replacement is not a simple direct replacement, but rather a DALI specialist or technician needs to redo the address matching process. Both the time and cost to perform the maintenance is detrimental to the proprietor.
  9. DALI is based on each fixture, as such its cost is much greater as compared with systems with circuits as the basic unit of control.
  10. During either the installation or maintenance process, there needs to be matching process and use of the specialized software, so when the electrician finishes with the installation, they are unable to perform any form of testing to verify that the installation is correct, but rather both the electrical and system personnel needs to be on site to perform the verification and commissioning. So not only is the equipment cost high, but the installation and maintenance labor costs are very high as well.

B.  D-Bus Lighting Control System

  1. The basic control unit of the D-Bus lighting control system is a circuit which can consist of any number of lighting fixtures, and not based on a single lighting fixture, thus it can service a lot more lighting.
  2. A single controller can have from 4 to 6 channels with each controlling its own circuit. Up to 64 controllers means that the number of circuits can be from 256 to 512 (note that this is not just the number of individual luminaires); furthermore, D-Bus digital switches does not require having its own address.The D-Bus system can support a whole more luminaires than the DALI system.
  3. The controllers are installed within the flat control panels and is not in the ceilings together with the luminaires; thus, it is much easier to perform diagnostics and maintenance, making the process so much more convenient.
  4. The D-Bus system can be used with any lighting fixture, or LED power supply on the market, and thus there are no limits on the types of luminaire that can be used.
  5. The address on the controllers can be manually set directly from the DIP switches on the front of each unit itself; even groups and patterns can be set manually. Thus installation and maintenance is considerably simplified and convenient.
  6. The D-Bus system can make use of most sensors available on the market or any wall switch plate. Choices are nearly unlimited and replacement is easy.