DALI-2 System Design — Wiring, Addressing & Commissioning
From bus topology to scene programming — a practical DALI implementation guide.
DALI-2 Basics
64 devices per DALI bus. 16 groups and 16 scenes per bus. 2-wire control (polarity free) alongside mains power. Bi-directional: query lamp status, energy, and fault reporting. DALI-2 adds input devices (sensors, switches) to the standard.
DALI System Topology
| component | qty | notes |
|---|---|---|
| DALI Bus Power Supply | 1 per bus | Provides 16V DC to the bus |
| DALI-2 Application Controller | 1 per system | Stores scenes, processes inputs |
| DALI-2 LED Drivers | Up to 64 per bus | Each has unique short address |
| DALI-2 Sensors | As needed | Occupancy, daylight, push-buttons |
| DALI Bus Cable | 300m max | 1.5mm², polarity free, star/daisy/tree |
Wiring Rules
DALI bus cable runs alongside mains cable in the same trunking (permitted, unlike DMX). Maximum bus length is 300m with voltage drop <2V. Any topology works: star, daisy-chain, tree, or mixed. Keep bus cable away from high-frequency interference sources (VFDs, large motors).
Commissioning Process
1. Install all hardware and verify mains connections. 2. Power up DALI bus and verify all devices are detected. 3. Auto-address devices (assigns short addresses 0–63). 4. Map physical locations to addresses using a walk test. 5. Assign devices to groups. 6. Program scenes (dim levels per group). 7. Configure sensor behaviors. 8. Test all scenes and failover.
