Basic Knowledge of DALI LED Driver Applications by MOONS'
Basic Knowledge of DALI
Digital Addressable Lighting Interface (DALI) is a two-line bi-directional serial digital communication protocol. Each device is assigned a unique static address in the numeric range 0 to 63, making possible up to 64 devices in a basic system. Addresses may be arbitrarily assigned and devices need not be mapped to contiguous addresses (gaps may exist in the address map). DALI gateways can be used to implement systems that have more than 64 devices. Data is transferred between controller and devices by means of an asynchronous, half-duplex, serial protocol over a two-wire bus. Considering this, no polarity requirement has been put forward during installation for signal lines that need to be separated from the main power line not shielded.
DALI is a digital lighting communication system developed by lighting manufacturers due to the demand of energy conservation. Standardization of DALI has accelerated both popularization and application of group control and intelligent energy-saving lighting products. As a standard protocol of lighting interface, DALI has been always favored by lighting manufacturers in the circle because of flexibility and low prices.
DALI-2 is an update of DALI, according to which, not only have 101 and 102 protocols been updated, but a 103 protocol is also additionally adopted. (Note: 103 protocol is a DALI control unit.) DALI-2 in fact is DALI-1 with some additional features that are relevant for sensors and control devices in the DALI network. On this basis, only 1 DALI address is required to realize color temperature or hue control by a single one power supply of multiplexed output.
MOONS’ dual drive is DALI-2 compatible. Each dual DALI drive has two (or four) DALI-2 DT6/8 LED outputs. With driver for Tunable White, one LED output controls the intensity of the overall light output, and the other controls the CT mix of the 2 LED outputs.
3. The Feature of DALI Lighting System
1. One bus tunnel of DALI master can support 64 DALI addresses at most. 2. DALI master communicates with DALI power supply according to the DALI protocol. 3. Every DALI power supply is Addressable individually. 4. Every DALI power supply can store 16 kinds of lighting scenes. 5. An identical DALI power supply can be edited into 1 group or other groups and the maximum marshalling number is 16.
4. The Framework of DALI Lighting System
Fig.1 DALI Lighting System Framework
A DALI lighting control system is generally composed of the following DALI products as shown in the figure above, namely, DALI power supply, lamp, dimming control panel, master control, sensor and computer.
5. Specification List of DALI Signal Line Length
Communication speed of DALI signals is 1,200bps and the signal transmission distance is subjected to constraints of the specification of the signal line. 101 protocol of version 2.0 has been defined as follows.
A in mm2
Maximum cable length L in m
a Cable lengths of more than 300 m are not recommended.
6. Signal Line Connection for MOONS’ DALI drivers
MOONS’ DALI drivers not only adopt bus connection but also run with daisy chain connection. As for bus connection, all signal lines of power supply should be connected to the bus, which makes it inconvenient for field application.
Comparing with LED drivers on the market, MOONS’DALI driver has 2 sets of DALI±SIGNAL ports and support one input and one output connection (Daisy chain connection). However, it is still a bus mode that is beneficial for reducing trivialness and time consumed during implementation.