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D4i specifications

D4i – A new logo and certification program for intra-luminaire DALI

D4i extends the existing DALI-2 certification program with additional features and functions, creating new possibilities for DALI in the IoT world.

>> Download the D4i press release

Certification and logo

D4i certification will be available for DALI-2 products that have a specific set of features required for intra-luminaire DALI. These features relate to power, diagnostics and energy metering.

D4i-certified products—including control gear for LEDs (drivers), as well as control devices such as sensors and wireless communication devices—will be eligible to carry the new D4i logo, which is a DiiA Trademark.

D4i-certified products will be eligible to carry the new D4i logo, which is a DiiA Trademark. D4i certification is an extension of DALI-2 certification, so all D4i-certified products are also DALI-2 certified.


D4i brings standardization to intra-luminaire DALI in two key ways:

First, D4i standardizes the way in which data is stored and accessed in DALI-2 drivers. This enables smart luminaires that are capable of participating in the IoT. The relevant DiiA specifications are Parts 251-253, which cover the storage and retrieval of data related to asset management, energy usage, diagnostics and maintenance (see below for more details).

  Relevant DiiA specifications

Data specifications
(Define how data
is stored, accessed
and reported)

DALI Part 251 – Memory Bank 1 Extension
- Covers luminaire-related data for asset management
DALI Part 252 – Energy Reporting
DALI Part 253 – Diagnostics & Maintenance

Second, D4i also defines how a driver with an integrated DALI bus power supply can provide power to a connected DALI device on the bus. Within a single luminaire, 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, an auxiliary 24V power supply is also included in the D4i specifications.

  Relevant DiiA specifications
DALI Part 250 – Integrated Bus Power Supply
AUX Power Supply

>> More information on DiiA specifications

Data specifications (DALI Parts 251-253)

DALI Parts 251-253 standardize the storage and retrieval of data in the DALI memory banks of a DALI-2 driver.

The DALI Part 251 specification describes how to store luminaire-specific information that has no impact on the functionality of the driver. For example, a manufacturer can encode data about the luminaire – such as part number, or nominal light output – in the factory. When the luminaire is installed, the data is readily available to the lighting-control network. A utility company or lighting-installation owner could use this capability to monitor and manage their lighting assets accurately and efficiently.

The DALI Part 252 specification standardizes the storage and reporting of data relating to the driver’s usage of energy and power.

DALI Part 253 focuses on diagnostics and maintenance, and covers a wide variety of data related to the driver, light source and luminaire.

>> Download the DiiA specifications

>> View the Case Study: "Intra-luminaire DALI enables Georgia Power to fast-track smart lighting project"


The D4i logo and word mark are Trademarks owned by DiiA, and their use is restricted to DiiA members. Guidance for usage is available.

>> D4i Trademark usage (members only)


What is intra-luminaire DALI?
As the name suggests, intra-luminaire DALI refers to a DALI bus within an individual luminaire, connecting the LED driver(s) with any DALI-2 control devices. 

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

When will D4i certification be available?
DiiA expects that D4i certification will be available in the third quarter of 2019, as an extension of DALI-2 certification.

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. Details can be found in the DiiA specifications—Parts 251 to 253.

What are the necessary criteria to achieve D4i certification?
LED drivers will need to implement Part 207 and Parts 250-253. In addition, the default state of the integrated bus power supply must be “on”.

Can the D4i logo be used on sensors?
Yes, D4i certification will be available for sensors and other control devices. DiiA is writing a new specification to define the D4i requirements for such devices.

D4i specifications for intra-luminaire DALI