D4i is a new DiiA specification that defines the DALI protocol in the Internet of Things (IoT) age.

A DALI specialist would claim that D4i is ideal for intra-luminaire DALI.

Should we anticipate this to happen? And what exactly is an intra-luminaire?

Let's have a look at how D4i varies from other DALI versions.

1. D4i 

1.1 D4i Overview

D4i is a DALI-2 function extension. It is an extension of the DALI-2 certification. It aims to increase support for data-related functions, including lighting assets, energy and operation based on the intelligent IoT lamps and DALI-2 lighting control. Collection and analysis of data such as diagnosis.

D4i is the DALI standard for Internet of Things compatibility (IoT).

Based on the DALI-2 feature, the intelligent D4i LED control device (LED driver power supply) in the D4i lights may be fixed in standard formats and output lamp asset data, energy data, and diagnostic data. The controller's installation interface requirements on the lights make it easy to put sensor and communication devices on the lamps.

Intelligent D4i bulbs are suitable Internet of Things nodes. D4i sensors and D4i control gears can collect data for performance monitoring, asset management, predictive maintenance, and other functions. Through the D4i controller's wireless connection features, these data may communicate and exchange with the external network.

D4i is an expansion of the DALI-2 certification scheme, and it covers two categories of devices: control gear/LED drivers and control devices.

To provide the data support of intelligent lighting in the Internet of Things era, the D4i expansion function is primarily as follows:

• Lamp monitoring with telecommunications interest

• Lighting asset monitoring

• Lighting debugging data interaction

• DC auxiliary power supply

• Bus power supply

Beginning in October 2019, ANSI developed ANSI C137.4 on the D4i standard (American National Standard for Lighting Systems-Digital Interface with Auxiliary Power), which includes the D4i standard regarding DALI.

The bus supply (DALI Part 250), auxiliary supply (DALI Part 150), and lighting information (DALI Part 251), as well as the applicable standards of other D4i, have recently been introduced. This means that, in addition to becoming the popular standard in Europe, D4i will also become the mainstream standard in North America for smart lighting. D4i can also be used in conjunction with socket-type connections that support hot swap and intelligent lighting, such as Nema/ANSI C136.41 and Zhaga Book18 and Book20 definitions.

1.2 D4i LED control gear

DALI data support capabilities, including parts 251, 252, and 253, must be supported by LED control gear that fulfils the D4i certification standard.

• DALI Part 251: Data on light fixtures

• DALI Part 252: Energy information

• DALI Part 253: Data debugging to support the bus supply and, optionally, the assistance auxiliary DC power supply:

• DALI-250: Power supply for DALI integrated bus (mandatory)

• DALI-150: AUX (additional power supply) (optional, LED driver for outdoor or high-power industrial)

The D4i LED driver has a DALI bus power source that can power the DALI control device attached to the bus. The ability to incorporate DALI sensors or other control devices that are exclusively powered via the DALI bus in the application of smart lighting. Auxiliary 24V power supply is also necessary for control devices with high power needs (such as wireless communication control equipment for road lights).

It can be integrated into the LED control device, or it can be provided by separate power equipment.

1.3 D4i control device

DALI 351 is a standard for D4i control device, and control equipment that can be installed inside the lamp or connected to the lamp. The D4i device requires DALI bus or auxiliary power supply.

DALI Part 351 defines the standards of four different types of control devices (A-D), and also stipulates the specific requirements of the power consumption of the device. It defines how to determine which control device priority when there are multiple control devices. Type A-D includes indoor and outdoor applications, including wireless network lighting controllers, light sensors, motion sensors and timers.

2. Common device type DT (DT6, DT8)

When talking about DALI control, we often hear people say DT6 or DT8. What do they mean?

DALI has a two-way communication function with lamps. You may check if the lamps are operating correctly and the strength of the lighting. Since its inception, the DALI protocol has been expanded several times, and each new device has been allocated a new number (device type X = DTX). The most recent significant modifications are emergency light (DT1), LED (DT6), and RGB/tunable white light control (DT8). The components of the IEC 62386 standard are depicted in the figure below. DALI DT8 and DALI DT6 are the company's control systems. While one is for color-controllable luminaires, the other determines the extent of the control gears.

But how are their respective systems designed to handle their individual controls?

2.1 DT6-LED Driver or control gear

Part 207 specifies the characteristics of control gear, a device type 6. The Device Type 6 is shortened as DT6 for simplicity, hence the DT6 is DALI Dimmable LED DRIVER. It is clear from the DALI standard organisational structure that the DT6 control devices must fulfil the three standard criteria of Part 101, Part 102, and Part 207. The DT6 is now the market's biggest DALI product type. LED drivers with constant current and constant voltage are the most common product forms, and they are widely used in outdoor and indoor lighting control systems.

2.2 DT8-Color Control Device

Device Type 8 is abbreviated as DT8 (color control device). However, unlike DT6, the type designation of the DT8 does not appear to correspond to a specific light control device, nor does it appear to correspond to a specific product like Device Type 7 (switch control device). It is simply indicated in part 209 that its defining object is a control device that can modify the output colour. It might be the LED lamp control device or another sort of light source lamp control device. Only the advancement of lighting technology has resulted in the majority of scenarios where the control device that supports DT8 is the LED lamp control device that supports light output colour. DT8 also refers to a DALI tunable white LED driver or a multiple output LED driver. DT8 control gears must fulfil three standard standards in terms of real application requirements: Part 101, Part 102, and Part 209.

If the light colour needs to be adjusted in the application prior to the standard formulation of the DT8, the general approach is to use two DT6 devices to connect CW (cold white) and WW (warm white) two different colour temperature sources of different colour temperatures, and then adjust the two-way control device output level through the master, so the colour temperature and brightness can be changed.

If you wish to change the RGB colour temperature, you'll need extra DT6 devices to connect other colours of light sources. Only DT6 can achieve the goal of altering the colour temperature or RGB colour of the lamp based on the results of the adjustment. However, there is a clear downside to this method:

• The bus must have two or more control devices/addresses.

• The colour temperature or RGB colour adjustment features are all finished on the side of the master controllers, making consistency and compatibility difficult to ensure.

• Using numerous separate control devices can raise the system's cost and complexity.

It also necessitates a larger installation area. To comply with the DT8 standard control device and occupy just one address, the colour adjustment characteristics are incorporated to the internal, so it can solve the aforementioned difficulties well and is easy to use. Because the new device types DT24 (Tc) and DT25 (xy) can be combined to replace it, the content of the DT6 and DT8 specifications will be greatly reduced until the protocol version is updated until gradually abolished.

2.3 The difference between DALI DT8 and DALI DT6

Let us summarize the difference between these two in fewer characters:

2.4 Summary

We can fairly say that DT8 reduces time, personnel, space, complexity, and expenses because:

• A DALI DT8 fixture employs a single DALI short address to handle two or more outputs on an unique DALI DT8 LED driver. As a result, it considerably decreases the number of such addresses and LED drivers required for color-changing control.

• DALI DT8 only requires one address for tunable white control, but DALI DT6 requires two addresses.