“DALI-compatible” is not enough information to close out a contemporary controls submittal. A project may be using a conventional DALI control bus between fixtures, sensors, and a controller, or it may be relying on a luminaire-mounted control node that expects power and standardized data inside the fixture. Those are related applications, but they are not the same one.
The practical distinction is this: DALI-2 is the current certification program for a range of DALI devices in a lighting-control system, while D4i extends DALI-2 for intelligent, IoT-ready luminaires and their luminaire-mounted control devices. Every D4i device is also a DALI-2 device, but a DALI-2 device is not automatically D4i. The DALI Alliance product database is the useful final check because it identifies the specific certified product, not merely a protocol claim in a catalog.
This guide helps designers, specifiers, and reviewers ask for evidence that matches the proposed controls architecture. It does not replace the electrical or controls engineer’s sequence, drawings, commissioning plan, or local-code review.
Begin with the control architecture
A DALI-2 system has three basic device types: control gear such as LED drivers, control devices, and bus power supplies. Control devices include application controllers, which make decisions and issue commands, and input devices such as occupancy sensors, light sensors, pushbuttons, and sliders. The DALI Alliance explains that the bus carries both communication and DALI power on the same pair of wires; each DALI-2 subnet can support up to 64 control-gear devices and 64 control devices. Its system overview also identifies the bus power supply as a required part of every DALI-2 system.
That framing avoids a common review error: treating the fixture driver, sensor, and controller as interchangeable “DALI devices.” They serve different roles. An input device supplies information; an application controller uses information and sends commands to control gear. The DALI Alliance’s control-device guidance makes that separation explicit. A submittal should show which proposed product fills each role instead of assuming that a sensor or driver provides system control by itself.
For a conventional interior controls package—such as troffers, linear lights, sensors, wall stations, and a panel or room controller—start with a DALI-2 system diagram. Identify the controller, every input-device type, the control gear in each luminaire, the DALI bus power source, and the intended subnet boundaries. Then compare that diagram to the sequence of operations and lighting-control zoning, not just to a fixture schedule.
What DALI-2 certification proves—and what it does not
DALI is the digital communication protocol defined through IEC 62386 and related DALI Alliance specifications. DALI-2 is a certification program based on the current protocol. The program applies to more than LED drivers: it also covers application controllers, input devices, and bus power supplies. Products must complete the certification process and have results verified by the DALI Alliance before they are listed and eligible to use the DALI-2 trademark. The Alliance’s certification overview describes both the verification step and the public product listing.
That is valuable for multi-vendor projects. The older DALI version-1 framework did not include control devices or bus power supplies in its certification scope. DALI-2 introduced defined requirements for control devices and more detailed, independently verified test sequences intended to improve interoperability. The Alliance’s DALI-2 comparison is a concise explanation of that difference.
Certification is not a substitute for design coordination. It does not establish that the selected controller contains the project sequence, that every fixture is assigned to the correct zone, that emergency operation is coordinated, or that a wireless gateway is included and programmed. It also does not make two products equivalent merely because both use a DALI mark. Review the specific device types, functions, firmware and hardware identity, system capacity, and commissioning responsibilities required by the job.
Where D4i adds requirements
D4i is aimed at intelligence inside the luminaire. A D4i LED driver has mandatory power-supply and standardized-data features that support luminaire-mounted sensors or communication devices. The standardized data can include luminaire, energy, and diagnostics information for uses such as monitoring, asset management, and maintenance. The D4i overview describes D4i as an extension of DALI-2 and notes that DALI Data specifications for luminaire, energy, and diagnostics data are mandatory for D4i LED drivers.
This matters most when the basis of design calls for a controller, sensor, or wireless node at the fixture. D4i can provide the defined internal control and power context that a luminaire-mounted device expects; it is not simply another name for a room-level DALI controller. A D4i-enabled area-lighting project may, for example, use a compatible control device in a socketed ecosystem, while an indoor DALI-2 system may use separate bus devices and a centralized or room-level controller. The appropriate architecture comes from the drawings and sequence—not from choosing the more elaborate logo.
D4i is also compatible with socketed connector systems such as NEMA/ANSI C136.41 and Zhaga Books 18 and 20, according to the DALI Alliance D4i overview. Compatibility does not mean that every socket, node, driver, or fixture combination is supplied in the proposed catalog number. Ask the manufacturer to identify the exact offered socket, node, driver, and certification status.
Request evidence at the offered-product level
Treat a family brochure as a lead, not as final proof. The DALI Alliance says the database record applies to the specific tested product and depends on the listed brand, GTIN, hardware and firmware versions, and valid product identity. Its product-database guidance is therefore especially useful when a submittal substitutes a driver or control node.
For each controls-related fixture and device, request:
- The complete proposed catalog number, including driver, sensor, control-node, socket, and voltage options where applicable.
- The role of the product in the system: control gear, input device, application controller, bus power supply, gateway, or a combined device.
- A DALI-2 or D4i certification claim tied to the actual proposed product, plus the corresponding product-database record when certification is required.
- The relevant implemented device type or part—not merely a generic “DALI-2 ready” statement. This is particularly important for sensors; the Alliance identifies separate DALI-2 parts for pushbuttons, absolute inputs, occupancy sensors, and light sensors. See the DALI sensor guidance.
- The luminaire data and auxiliary-power requirements for any fixture-mounted D4i device, and confirmation that the selected driver and node are supplied together as proposed.
- A controls riser, wiring topology, bus-power source, device quantities, addressing approach, and subnet capacity that agrees with the control drawings.
- The written sequence, startup responsibilities, functional-test process, and handover records.
The electrical and controls teams should review voltage, conductor selection, topology, device loading, and all project-specific limitations. The Alliance describes a typical DALI bus power supply as 16 V and up to 250 mA, but those typical values are not permission to skip the proposed manufacturer’s installation instructions or project engineering. Its cabling guidance is system context, not a stamped design.
Keep the review aligned with commissioning
The best submittal establishes a direct path from product selection to a testable sequence. Make the controls contractor show how each sensor input reaches an application controller, how that controller operates the specified driver groups, and where timeouts, daylight response, scenes, and overrides are documented. The lighting-controls sequence-of-operations checklist can help turn that information into a commissioning-ready review package.
For substitutions, repeat the exercise. A different DALI-2 controller may have a different capacity or device-type support; a different D4i node may need different fixture hardware, power, or configuration. Do not approve an alternate solely because its driver dims or its marketing sheet uses the phrase “DALI.” Ask for the offered assembly’s certification evidence and the revised system diagram.
The takeaway
DALI-2 gives a project a verified interoperability baseline across the DALI control system. D4i builds on that baseline inside an intelligent luminaire, with standardized data and defined power-related capabilities for luminaire-mounted devices. Select the architecture the sequence actually needs, verify the exact proposed products in the DALI Alliance database, and require the submittal to identify every system role, bus-power source, and commissioning responsibility. That turns a protocol label into a coordinated controls package.