The digital addressable lighting interface (DALI) is designed for use in building installation engineering. It is universally usable for functional lighting from the simplest lighting tasks (plug and play) to highly complex control applications. The interface was developed in the late 1990s and has been standardised globally in standard IEC 62386 since 2002. Since 2014, a fundamental further development of the interface, DALI-2, is in the works, which is increasingly becoming established on the market.
The following DALI interface performance characteristics have been proven and tested in practice:
Its dimming curve is standardised. Even different light sources can be dimmed uniformly at once.
Luminaires can not only be dimmed but also switched via interface.
The polarity of the interface in general must not be considered (see chapter ). Malfunctions due to polarity reversals during luminaire installation are therefore excluded.
The two-core DALI control line can be installed in a joint sheathed cable with the voltage supply (5LV – see chapter ).
Many other DALI functions are also defined.
Commercially available DALI control devices are often designed for certain applications and only access a portion of defined DALI functions. Construction and operation of DALI control devices, design of operating panels used (push-button, touch panel etc.) as well as the range of supported functions are not defined in the DALI standard.
DALI control gear units, however, are universally usable – meaning compatible with any DALI control device – if they feature the DALI logo (see section “DALI parameters and initialisation” at the end of chapter ). For colour control applications, other aspects may require consideration. In some cases, so-called DT8 control gear units can be used (see chapter ).
There is a distinction between two communication principles:
DALI broadcast mode (direct DALI) – all participants collectively follow one control signal.
DALI addressing mode – every participant receives an individual address that facilitates individual operation, with the number of possible addresses being limited to 64.
The DALI interface thus serves communication between one control device (master) and several control gear units to be controlled (slaves). This basic function, in contrast to the aforementioned interfaces, is optimised for functional lighting applications through a detailed definition of the standard.
The DALI-2 interface offers fundamentally expanded functionalities on top, such as:
parallel operation of several control devices (multi master operation), and
connection and operation of standardised light sensors,
standardised presence sensors and
at one joint control line with the control gear units.
These functions have proven to be expedient supplements regarding frequently occurring lighting tasks.