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D4i overview

D4i certification enables DALI inside intelligent, IoT-ready luminaires

By taking care of control and power requirements, D4i makes it much easier to mount sensors and communication devices on luminaires. In addition, intelligent D4i LED drivers inside the luminaire have the capability to store and report a wide range of luminaire, energy and diagnostics data in a standardized format.

Smart D4i luminaires are ideal platforms for the IoT, capable of gathering information from on-board D4i sensors, and providing data for performance monitoring, asset management, predictive maintenance and many other tasks. Communication and data exchange with an external network can take place via a D4i control device with wireless communication capabilities.

D4i is an extension of the DALI-2 certification program. D4i LED drivers have a mandatory set of features related to power-supply requirements and smart-data capabilities. 

>> D4i for LED drivers

>> D4i for control devices

>> Download DiiA Specifications

>> Find out how D4i is used in outdoor lighting applications



The D4i logo and D4i wordmark are trademarks in various countries in the exclusive use of the DALI Alliance. Use of these trademarks is restricted to DALI Alliance members only. 

>> Download the DiiA Requirements document "D4i Certification and Trademark Use"



DALI Alliance members are now able to certify their D4i LED drivers and control devices in a procedure that includes independent verification of test results.

>> More details on D4i certification

Certified products are eligible to carry the D4i logo trademark, which can also be used on qualifying luminaires.



D4i is harmonized with the North American ANSI C137.4 standard >> More details

D4i is also compatible with socketed connector systems such as NEMA/ANSI C136.41 and Zhaga Books 18 and 20.

The DALI Alliance and Zhaga have launched the joint Zhaga-D4i certification program for D4i luminaires with Zhaga sockets which can accommodate D4i control devices.


D4i for LED drivers

Data specifications 

The DALI Data specifications (Parts 251, 252 and 253) are mandatory for all D4i LED drivers. >> More on DALI Data

  D4i requirement
DALI Part 251 – Luminaire Data Mandatory
DALI Part 252 – Energy Data Mandatory
DALI Part 253 – Diagnostics Data Mandatory


Power-supply specifications

  D4i requirement
DALI Part 250 – Integrated Bus Power Supply Mandatory
DALI Part 150 AUX Power Supply Optional

D4i drivers have an integrated DALI bus power supply and can provide power to connected DALI devices on the bus. In luminaires, this greatly simplifies the incorporation of DALI sensors or other control devices that are solely powered from the DALI bus.

For control devices with higher power requirements — such as wireless communication devices for city-wide networks — an auxiliary 24V power supply is also required. This can be integrated into the LED driver, or can be a separate device. 

>> Download DiiA specifications


D4i for control devices

  D4i requirement
DALI Part 351 – Luminaire-mounted Control Devices Mandatory

DALI Part 351 is a specification for D4i control devices that can be inside or attached to a luminaire. D4i control devices are powered either from the DALI bus or from an AUX supply.

Part 351 defines four different classes of control device (types A-D), and includes specific requirements for power consumption. There is also a mechanism to decide which control device takes priority when more than one is present.

Types A-D cover both indoor and outdoor applications, and include devices such as wireless network lighting controllers (NLCs), photocells (light sensors), movement sensors and timers.

>> Download Part 351


D4i presentations

► D4i overview

► Smart Lighting with D4i-enabled Luminaires: Energy Reporting, Asset Management, Predictive Maintenance and more

>> Available here


D4i products

All certified D4i products are listed in the Product Database. Unlisted products are NOT certified and should not be considered as compatible with D4i specifications. 

The following links show different D4i product types in the Product Database. Note that some devices combine application controllers and sensors in the same product. 

>> D4i LED drivers
>> D4i application controllers
>> D4i sensors



>> Download a detailed set of Q&A from the D4i webinar presented by DALI Alliance member Synapse.

Introductory questions:

What is the difference between DALI-2 and D4i?
For LED drivers and control devices, D4i is an extension of DALI-2 certification. D4i products are DALI-2 products that have a specific set of features. All D4i-certified drivers and control devices are also DALI-2 certified. Such products can optionally carry either the D4i logo or the DALI-2 logo, or both.

What data can be read out from a D4i driver?
Data related to asset management, energy usage, diagnostics and maintenance can be stored in and retrieved from the driver. More details here or see the DiiA specifications Parts 251 to 253.

What are the necessary criteria to achieve D4i certification?
LED drivers need to implement Part 207 and Parts 250-253. Part 150 is optional. In addition, the default state of the integrated bus power supply must be “on”. Products must also meet the requirements listed in "D4i Certification & Trademark Use" (download here)

Can the D4i logo be used on sensors?
Yes, the new D4i specification DALI Part 351 defines the D4i requirements for sensors and other control devices. 

What is intra-luminaire DALI, and is this the only use for D4i?
Intra-luminaire DALI refers to a DALI bus within an individual luminaire, connecting the LED driver(s) and control device(s). D4i is well-suited for intra-luminaire DALI use within stand-alone luminaires that do not have an external wired DALI connection. However, it is also possible to connect several D4i luminaires in a wired DALI network. 

How can I use multiple D4i luminaires in DALI systems?
To use multiple D4i luminaires together in the same DALI system, ensure the maximum bus power supply current of 250mA will not be exceeded. For example, a D4i luminaire with one driver may have a maximum bus power supply current of 60mA. Four such luminaires could be connected together on a DALI bus (the total maximum bus power supply current would be 240 mA). But if more than four luminaires are connected, then one or more of the bus power supplies will need to be disabled. For D4i drivers, this can be done using a programming tool before connecting the luminaire's DALI bus into the larger system.


D4i example: Two-node outdoor luminaire

The example below shows a two-node, outdoor-lighting application. Power is available to both nodes, which enables plug-and-play  socketed systems such as Zhaga-D4i. The intelligent luminaire has sensing capabiliites, and can report luminaire, energy and diagnostics data stored in the LED driver to the external network via the DALI bus and the wireless link.