What is DALI?

DALI stands for Digital Addressable Lighting Interface. It is an International Standard (IEC 62386) lighting control system providing a single interface for all Electronic Control Gears (light sources) and Lighting Control Devices (controllers).

The DALI  standard enables dimmable ballasts, transformers, emergency fittings and controllers from different manufacturers to be mixed and matched into a single control system. A DALI system provides designers, luminaire manufacturers, installers, building owners and end-users a powerful and flexible lighting control system with security of supply from many sources.

The DALI standard is overseen by the AG-DALI working group comprising engineers, manufacturers and institutions working in the field of digital lamp/luminaire control. DALI is effectively an enhancement on DSI control with the added advantages it has interoperability, status feedback and group control.

What is a DALI network?

A DALI network, sometimes called a DALI loop, consists of up to 64 DALI light sources (ballasts, transformers etc.), addressed from 0 to 63. DALI ballasts are controlled by commands that can be sent to individual ballasts, to groups of ballasts or to the entire network.

A DALI ballast is intelligent device that can be configured to remember its power-on level, maximum level, minimum level, system failure level, fade rate and fade time. A ballast can belong to up to 16 groups and store up to 16 preset scene levels. 

A true DALI network control system can report the level of every ballast and the status of every ballast and lamp. True DALI systems also enable controllers from multiple vendors to be used on the DALI network.

What are the components of a DALI network?

A DALI network consists of the following components:

• One or more DALI Power Supplies totalling a maximum of 250mA available current.
• From one to sixty-four DALI ECGs ie. ballasts, transformers, inverters, relay modules, exit signs etc.
• One or more DALI controllers such as a group controller, scene controller or loop controller.

Note that DALI controllers do not require an address on the DALI network but some controllers do draw power from the network. For example a typical group controller draws 6mA.

What is a DALI Control System?

DALI control systems can be scaled from single rooms to complete buildings and campuses.

A simple system could consist of a few light fittings and a switch connected to a DALI group controller. The switch provides on/off control and dimming of the fittings. Minimal configuration is required and ballasts do not need to be individually addressed.

A grouped system consists of multiple ballasts individually addressed on a DALI network. Addressing of the ballasts takes approximately 5..10 minutes for random addressing and 30 minutes for sequential addressing. Inputs on a loop controller or a group controller can be configured to provide switching and dimming as required. The functionality of the inputs depend on the controller's capabilities however typical examples include switches, pushbuttons, occupancy sensors and light level sensors. 

Multiple DALI networks can be linked together with DALI gateways or controllers that combine DALI networks onto an Ethernet backbone. Gateways require a centralized server to provide time scheduling whilst the more powerful controllers provide localized scheduling and control options in addition to the gateway functions. 

What are the advantages of DALI?

For lighting designers and consultants

• Distributed intelligence for flexible and reliable control
• Control of individual lights, groups and networks
• Easy configuration & reconfiguration for changing circumstances
• Simple interface with building management systems
• Logarithmic dimming behaviour matching the human eye
• Increased energy savings
• Options for emergency lighting

For installers and electrical contractors

• Simple 5-core wiring, no special control cable, no polarity, no termination and no segregation required
• Easy base-building commissioning
• Easy commissioning for tenancies
• Building lighting and emergency lighting on the one system
• No need to switch the mains voltage (handled internally by the ballasts)

For facilities managers & maintenance contractors

• Status reporting of lamps and ballasts
• Simple modification - no need to rewire for changing tenancies
• Lower maintenance costs
• Increased energy savings due to dimming and control capabilities

For building occupants & tenants

• Customized lighting preferences
• More comfortable lighting
• Individual control
• Easy modification