From human-centric lighting to dynamic ambient scenes, today’s lighting projects demand precise, flexible, and reliable color control.
In one of our recent projects, the customer needed to integrate new luminaires into an existing control system while controlling Tunable White and RGBW lighting in two groups. To meet these requirements, we selected floodlights equipped with DALI DT8 drivers.
As part of the DALI-2 standard, DT8 enables both Tunable White and color control by transferring much of the complexity from the control system to the LED driver itself. Instead of managing multiple channels externally, the driver handles color mixing internally, resulting in simpler commissioning, improved consistency, and more reliable performance.
So, what exactly is DALI DT8, and how does it simplify Tunable White and RGBW control?
What is DALI DT8
DALI (Digital Addressable Lighting Interface) is a two-way digital lighting control protocol allowing luminaires and control devices to exchange status information and commands.
Since its introduction, the DALI protocol has evolved through several expansions. Each new functionality is defined as a Device Type (DT), identified by a specific number. Some of the most important device types include:
- DT1: Emergency lighting
- DT6: LED drivers for single-channel white light dimming
- DT8: Tunable White and RGB/RGBW color control
DALI Device Type 8 (DT8) is defined in IEC 62386-209 and is specifically engineered for advanced color control applications. It describes how LED drivers communicate with control systems to manage Tunable White and full-color RGB or RGBW lighting.
A key advantage of DT8 is that it uses a single DALI address to control multiple LED channels. Complex parameters, such as CIE xy chromaticity coordinates, RGB color values, or Correlated Color Temperature (CCT), are transmitted as unified data sets. The DT8 driver then internally manages color mixing and intensity control, ensuring smooth transitions and consistent color output.
DT8 vs. DT6
Compared to DT6, DT8 offers significant advantages. Standard DALI with DT6 was designed primarily for basic dimming of single-channel white LEDs, where each channel requires its own address. In contrast, DT8 represents the “multitasking” evolution of DALI, enabling synchronized control of multiple color channels through a single address.
|
Feature |
DALI DT6 |
DALI DT8 |
|
Addressing Logic |
One address per channel (1 address for Dimming, 2 for Tunable White, 4 for RGBW). |
One address manages all channels (Dimming, CCT, and Color) simultaneously. |
|
System Capacity |
A single DALI loop (64 addresses) can only support 16 RGBW fixtures. |
A single DALI loop can support up to 64 RGBW fixtures. |
|
Wiring Complexity |
Heavy. Multiple cables and drivers are often required to manage different color channels. |
Simplified. Single-bus connection with integrated multi-channel drivers. |
|
Typical use |
Simple dimming |
Tunable white, RGB, RGBW |
How DALI DT8 Simplifies Tunable White Control
Tunable White lighting has become a cornerstone of human-centric lighting, enabling designers to adjust color temperature to support comfort, wellbeing, and circadian rhythms. Technically, Tunable White is achieved by blending two LED channels, typically one warm white and one cool white, to produce a wide range of correlated color temperatures (CCT).
Traditionally, this approach required two separate DALI addresses, one for each LED channel, along with independent dimming curves. This added complexity to wiring, programming, and commissioning, and often made it difficult to maintain a stable color temperature across the full dimming range.
With DT8, both the warm and cool white channels are controlled through a single DALI address. The color-mixing logic is handled inside the LED driver, while the control system simply sends high-level commands such as target CCT and brightness.
Another key feature of DT8 is standardization. Because the color control behavior is defined within the DALI standard, luminaires from different manufacturers respond in a more consistent and predictable way. This results in smoother fades, stable color temperature during dimming, and fewer unexpected results during commissioning. For large-scale projects, this consistency is especially valuable.
How DT8 Makes RGBW Control Simpler
For architectural projects that require vibrant color mixing, RGBW lighting is a good option. With DT6, controlling RGBW over DALI was messy. You needed four separate DALI addresses, one for each channel: red, green, blue, and white.
DT8 RGBW devices allow control of all four channels via a single DALI address. It also supports centralized RGBW color tuning and dimming under one address.
Beyond saving address space, DT8 introduces two control methods:
- xy-Chromaticity: This allows designers to pick an exact coordinate from the CIE 1931 color space. The DT8 driver then handles the complex math internally to mix the LEDs, ensuring that a "Deep Navy" or "Sunset Orange" looks identical across 50 different fixtures.
- Extended RGBWAF Mode: Innovative DT8 drivers can now operate in "Extended" mode, which allows the system to deliver full power to all four channels simultaneously. Unlike the older "Normalized" mode that capped total output, this ensures maximum brightness and "punch" for high-impact facade lighting or dramatic retail displays.
Case Study
Do you remember the project we discussed at the beginning? For this application, we selected the FL39 RGBW floodlight equipped with a DALI DT8 driver.
Because DT8 allows a single DALI address to control two or more LED channels, it perfectly met the customer’s requirements. The new luminaires could be seamlessly integrated into the existing control system while still allowing control of Tunable White and RGBW lighting across two separate groups.
This DT8-based solution also delivered several practical advantages, including simpler wiring, faster and easier commissioning, and more precise and flexible color control. In addition, optimized channel management within the driver contributes to improved energy efficiency and consistent lighting performance.
Today, DALI DT8 is widely used in landscape, facade, and human-centric lighting applications where dynamic and high-quality color control is essential.
If you need customized lighting solutions, feel free to contact us.
