Digital Addressable Lighting Interface

DALI Dimmable Control Gear

The application of dimmable control gear in luminaires has increased significantly in recent years with advances in the range and simplicity of products available. Tried and tested DSI technology (Digital Serial Interface) and the DALI interface protocol (Digital Addressable Lighting Interface) offer impressive flexibility – from individual intelligent luminaires and large room installations to lighting concepts for buildings that can even be linked to emergency lighting systems to provide a total package.

DALI (Digital Addressable Lighting Interface)

DALI is not a new system for building control such as LON, EIB and other management systems but a useful addition for the practical application of lighting controllers. DALI provides ideal support for Building Management Systems and enables each light source to be individually addressed. Even small installations in which a building management system would not be economical need not forego the convenience of digital technology. DALI can be used in installations as an independent lighting management system.

DALI is an interfaced protocol for digital communication between electronic lighting equipment in conjunction with a control system. The DALI standard is currently defined in EN 60929 Annex E and will in future be defined in IEC 62386. This standard also describes the differences between the various types of devices and as a result, the long term compatibility among component manufacturers is guaranteed and the DALI standard is ensured a secure future.

Features and benefits of the DALI system include:

• Simplified Installation – power lines and control lines can be laid together in the same cable and may be wired in series, star arrangement or mixed format.
• No Polarity – there is no need to worry about the polarity (+/-) of the DALI control line.
• Stable Dimming Function – all luminaires receive the same interference free digital signal and therefore the same dimmer value.
• Distributed Intelligence – DALI uses a system of distributed intelligence: multiple controllers communicate with intelligent ballasts. Each controller operates as a master and controls communication to the control line. Ballasts react only as slaves at the request of the master. Certain parameters are stored directly in the DALI unit eg; scene values, group addresses.
• Status Feedback – Status reports can be issued by the DALI units. Information on faulty lamps for example can therefore be transferred to a higher ranking system.
• Flexibility – Group assignment is set up by means of parameters and not by hard wiring. Lighting scene values are stored in the DALI unit.
• Logarithmic Dimming Curve – The dimming curve is matched to the sensitivity of the eye.