DALI2 has become the default control protocol for commercial lighting. It provides individual luminaire control, scene management, and seamless integration with building management systems. But specifying DALI2 correctly requires understanding the protocol, its capabilities, and its limitations.
What DALI2 Actually Does
DALI stands for Digital Addressable Lighting Interface. DALI2 is the current version, certified under IEC 62386. It uses a two-wire bus to send commands to individual luminaires or groups.
Each DALI2 bus supports up to 64 individually addressable devices. Each device receives a unique short address (0 to 63). Devices respond to individual commands, group commands (up to 16 groups), and scene commands (up to 16 scenes per device).
Why DALI2 Over Phase Dimming
Phase dimming is simpler and cheaper. It works by chopping the AC waveform. Leading edge dimmers suit resistive and inductive loads. Trailing edge dimmers suit capacitive loads like LED drivers.
Phase dimming has three fundamental limitations. It requires dedicated dimmer circuits for each zone. It provides no feedback from the luminaire. And dimming performance varies between driver manufacturers.
DALI2 solves all three. One bus connects up to 64 devices. Every device reports its status, including lamp failure, driver temperature, and actual dim level. Dimming curves are standardised across all DALI2 certified drivers.
DALI2 vs DALI1
DALI1 covered luminaires (control gear) only. DALI2 extends the standard to input devices (sensors, buttons, switches) and application controllers. This means the entire control system speaks one protocol, reducing integration complexity.
DALI2 also introduces mandatory certification testing. Every DALI2 device must pass interoperability tests at an accredited lab. This eliminates the compatibility issues that plagued early DALI1 installations.
System Architecture
A typical DALI2 system consists of three layers. The bus layer carries DALI commands over two wires (polarity independent). The control layer includes sensors, switches, and application controllers. The management layer provides supervision, scheduling, and BMS integration via gateways.
Bus topology is free. Star, daisy-chain, tree, or any combination works. Maximum bus length depends on voltage drop. With 1.5mm cable, expect up to 300 metres total wiring length.
Emergency Lighting Integration
DALI2 Part 202 defines the standard for emergency lighting control gear. This enables automated testing, status reporting, and log retrieval over the DALI bus. No separate emergency test systems required.
Self-test emergency fittings report function test results (monthly) and duration test results (annually) automatically. Building managers access test logs through the BMS or a dedicated DALI controller.
Commissioning Considerations
DALI2 commissioning requires address assignment, group configuration, and scene programming. Tools range from handheld programmers to PC-based software.
Allow adequate commissioning time in the project programme. A floor of 200 luminaires typically needs 1 to 2 days for full commissioning including sensor calibration and scene tuning.
Specifying DALI2 Luminaires
When specifying DALI2 luminaires, confirm the driver carries DALI2 certification (not DALI1). Check the device type (DT6 for LED drivers, DT8 for colour control). Verify the minimum dim level. Most DALI2 LED drivers achieve 1% minimum, but some budget drivers only reach 10%.
EMPRICS Lighting offers DALI2 options across our full product range. Every DALI2 product includes certified drivers with verified interoperability.