Plan the bus, not just the light count
The DALI Alliance guide describes a two-wire bus supporting up to 64 control-gear addresses and a separate set of up to 64 control-device addresses on a single bus. These are not a promise that every controller supports every device or that 128 arbitrary devices will fit the power budget. Multi-channel products can also affect addressing requirements.
The total maximum current available from connected DALI bus supplies must not exceed 250 mA; their guaranteed supply current must also cover the connected devices' consumption. Include integrated supplies, particularly D4i drivers. Do not simply parallel extra supplies to cure communication faults.
Use the actual controller/gear instructions for cable size, distance, permitted topology and voltage drop. Do not add DMX-style terminators or join different buses together without an appropriate interface. A typical DALI bus is polarity-insensitive, but all the other terminals on a driver certainly are not interchangeable.
Electrical safety
DALI control lines are not assumed SELV. Tridonic explicitly requires mains-equivalent working precautions for the DALI signals in its supply manual. Suitable insulation, segregation and isolation are installation design matters, not things to infer from the bus's usual low voltage. Never connect the bus to mains, Ethernet or PoE. This article does not provide mains wiring instructions.
How communication is organised
Control commands can target individual gear, groups or broadcast destinations. Gear can answer supported queries; newer control-device functionality includes input-event information for application controllers. Short addresses, groups and scenes are different concepts. Avoid unsolicited address changes or broadcast tests on an occupied installation.
Specification links and access
The normative DALI standard is the multi-part IEC 62386 series, normally purchased through IEC. The Alliance's standards page identifies the relevant parts and purchase routes. Its separate specifications download page provides selected DiiA extensions under stated terms; some documents require membership, and some earlier extensions have moved into IEC publications.
Use the free Quick Start Guide to learn the architecture, not as a substitute for normative requirements. For installation work, combine the exact product manuals, commissioning records and the applicable standards with a licensed installer's design.
Official reading
Quick Start Guide: bus power and addresses
IEC 62386 parts and purchase information
DiiA public/member specification availability
Manufacturer electrical-safety guidance