Technical Overview

DALI is a dedicated protocol for lighting control. A DALI system can be made up of control gear, control devices and bus power supplies.

Control gear

Control gear usually contains the power control curcuit to drive lamps, or some other type of ouput such as on/off switching or 1 to 10 V analogue signals.

Control devices

Control devices can provide information to other control devices (such as light intensity information), and can send commands to control gear. Input devices are a type or a part of a control device that provides some information to the system, such as a button press or movement detection. Application controllers are also a type or a part of a control device and are the decision makers in a DALI system – for example, they can send commands to control gear to modify the lighting.

Bus power supplies

At least one bus power supply must be present in a DALI system. This is necessary to allow both communications on the bus, as well as to power any bus-powered devices. The bus power supply does not need to be a separate unit – it could be part of another device such as an LED driver or a sensor.

In addition to the above, a DALI system also includes the bus wires that are used to connect together the DALI terminals of the various devices in the system.

Technical basics

Modern lighting technology requires systems that are flexible, simple and that provide room-based lighting control with just a few lowcost components. Its wiring needs to be easy, minimum combined with user-friedly operation.

The digital simplicity and flexibility of DALI enables customers to create solutions that are easy-to-use, robust, interoperable and above all energy efficient and affordable.

Technical boundaries

  • max. 64 devices per subnet (Hub/Routers)
  • max. 300m cabling
  • max. 250mA device consumption

Cabling benefits

  • Standard 2-core cable (1,5mm2)
  • Polarity free & Free wiring topology
  • DALI power and data on same pair of wires

Digital benefits

  • Robust communication
  • Individual (64), grouping (16) and broadcast (all)
  • Changes via software
  • Two-way communication (feedback)

Addressing

One of the benefits of DALI is the flexibility in the way that devices may be addressed.

At the simplest level, all devices are addressed simultaneously by broadcast commands. This can allow control of lighting in a similar manner to 1-10V analogue control, without requiring any configuration of the individual devices. If a level (Direct Arc Power Command) is broadcast, then all control gear will act upon that command, changing their output to the same new level.

With simple configuration, DALI devices can be given one of 64 short-addresses. This allows individual control, configuration and querying of any single device in the system.

DALI devices can also be group addressed. For example, a DALI LED driver could be programmed to be in any combination of the 16 available groups. When a command is sent to a group, only devices that are in that group will be addressed. As the standard expands to include control devices, further addressing methods will be allowed.