Optoelectronics
DALI application controllers can support multiple subnets, which may comprise any combination of DALI+ and wired DALI subnets (Figure 4).
Figure 2: In a wired/wireless hybrid scenario, the office luminaires each have a gateway that forms part of the wireless network. In the corridor, a wired DALI line connects all the luminaires with a single gateway that also participates in the wireless ecosystem.
system around DALI is that the protocol was developed specifically for lighting and has tailored lighting-control features, as well as providing access to luminaire, energy, and diagnostics data. Other protocols cannot offer the same rich and broad set of standardised, lighting-specific features.
Figure 2 illustrates an example of gateway use in two scenarios. In the corridor, a single gateway allows the wireless ecosystem to control a wired network of DALI luminaires. In the office, each luminaire has an individual gateway that shares the wireless network with other wireless controllers and sensors.
What does DALI+ offer? The second approach to wireless lighting control is DALI+, which uses DALI over wireless or internet protocol (IP)–based networks. DALI+ devices communicate using existing DALI commands carried over a wireless or IP-based link, rather than the dedicated pair of wires used by DALI-2 and D4i.
DALI+ builds on the proven DALI lighting- control features in wired systems and offers access to the same data from control gear, luminaires, and sensors. All DALI control gear and control devices standardised under IEC 62386 can be implemented in DALI+, including LED drivers, colour-controllable drivers, emergency drivers, application controllers, push buttons, and sensors.
other Thread features, such as self-healing and automatic configuration. DALI+ with Thread also allows the use of IPv6 addressing, which means the number of devices in a DALI+ system is virtually unlimited for all practical purposes.
Figure 3: DALI+ enables devices to communicate using existing DALI commands carried over a wireless medium. Bridges link wired and wireless networks, using the DALI protocol throughout.
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Other Thread devices may be used in the same Thread network as the DALI+ devices, increasing flexibility for system designers to add non-DALI devices such as sensors or door access hardware. Thread border routers allow
specific capabilities, such as precise dimming and colour control.
For offices, homes, factories, and other smart buildings, the combination of wireless and DALI brings unparalleled flexibility and control, along with a roadmap to add new standards and features in the future. DALI is a registered trademark of the DALI Alliance.
https://www.dali-alliance.org/ Components in Electronics June 2024 25
In some systems, there may be a need to combine DALI+ and existing wired DALI systems or luminaires. The DALI commands and features are the same for DALI+ and wired DALI. A new type of device known as a bridge enables application controllers in the DALI+ network to access and control the DALI wired control gear and control devices (Figure 3). For more complex systems, a backbone such as Ethernet can be used to connect multiple wireless DALI+ systems. Additionally,
Which network protocols can be employed? Several wireless technologies can be used for lighting control. Typically, it makes sense to use a widely adopted standard to increase flexibility, avoid lock-in to one particular vendor, and leverage interoperable hardware devices from various suppliers.
The DALI Alliance has published two gateway specifications to
cover wireless-to-DALI gateways with either Bluetooth mesh (Part 341) or Zigbee (Part 342). The same certified DALI-2 or D4i drivers can be used with either a Bluetooth mesh or a Zigbee gateway.
Initially, DALI+ supports Thread, an IP- based, low-power, wireless mesh networking protocol using 6LoWPAN wireless technology. Thread’s existing authentication and encryption methods ensure security, and the DALI+ lighting system can take advantage of
connection through other IP-based physical layers — for example, Ethernet or Wi-Fi — which supports highly scalable systems. The use of an IP-based carrier, such as Thread, for DALI+ also opens the possibility to integrate the lighting system with other functions, such as HVAC or building access, via a building’s IT infrastructure.
Conclusions
DALI is the established standard for digital lighting-control systems, and the DALI Alliance now enables lighting system designers to work with wireless connectivity supported by proven technology and wide industry adoption. The DALI Alliance is developing robust certification for the new wireless approaches. There are two distinct options for wireless: Wireless to DALI gateways allow existing DALI-wired products to be used in a non-DALI wireless system; and DALI+ enables devices to communicate using existing DALI commands, carried over a wireless or IP-based medium. Whichever option best suits lighting designers, the addition of wireless to the familiar DALI standard extends choice and creative freedom. At the same time, it ensures designers can rely on rigorous standardisation and certification, along with DALI’s lighting-
Figure 4: An example of a complex system comprises two wireless Thread networks connected with an Ethernet cable via Thread border routers. A DALI+ bridge provides connectivity to two DALI wired buses (one of which is a D4i luminaire), and a multi-subnet application controller provides interfaces to two further wired subnets.
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