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Digital Lighting Control. Which To Choose: DALI or KNX?

Feb. 26, 2022

The common digital lighting control in Europe even worldwide spread is DALI (Digital Addressable Lighting Interface). DALI is specified by a series of technical standards in IEC 62386. Standards conformance ensures that equipment from different manufacturers will interoperate.


Another approach is to utilize KNX lighting in building automation which is similar to DALI originated in Europe and operate by an organization in Brussels. Devices from different manufacturers can run smoothly because all products are subjected to be tested by a third neutral test laboratory to ensure interoperability.


Minimal dimming level: DALI vs. KNX

The human eye does not perceive changes in light level in a linear manner and slight variations in perception occur between individuals. This response results in a difference between measured and perceived light levels.

The linear curve gives the output of the driver the same as the command sent from the push button.


DALI curve is based on a formula specified in the DALI standard which gives the user an outstanding dimming experience. It is because the light difference between steps is designed to be constant and the minimum dimming level is 0.1% (equivalent to 3% perceived light) according to DALI standard.

 DALI Led Tracklight

 DALI Led Tracklight     

Log curve gives the logarithmic response. It is worth mentioning that minimal output of the log curve gives only 0.01% (equivalent to 1% perceived light) which opens the possibility for some applications where low luminescence is needed.


User is free to select one of these three curves to achieve the best result. The depth attenuation performance test performed using a 24Vdc LED strip shows that it is possible to obtain a lower light intensity better using the PWM KNX driver log curve than the DALI-based driver.

PWM dimming frequency

The light change of constant voltage LED lamp is in general realized using PWM (Pulse width modulation) by adjusting the duty cycle of the current which results in changes to the average current. PWM is effective for accurate light dimming requirements handling high dimming ratios at higher frequencies to avoid the light flicker and stroboscopic effect while maintaining minimal effects to the LED color temperature.


Generic DALI LED driver has a fixed output frequency at several hundred hertz depending on a design from manufacturers. Higher frequency design is preferred however it is compromised to maintain product reliability for the reason that more switching lost at the component inside the driver is produced.

Fashion Lighting

 Fashion Lighting


LED strip application

After ETS programming, the driver is placed to where the final location is and the LED strip is connected to the output of the driver. Then KNX cable is connected for telegram commission followed by the connection to 230V a-c mains voltage. When the driver received the command from the push button or any other KNX input device, the light is controlled to turn on, off, or dim.


The second application is to drive a 12Vac LED lamp for spotlighting. The benefits are including the true replacement of low voltage halogen M R sixteen lamp which means even end-user could replace the lamp without safety concerns. one to one lamp size replacement. Long lifetime and it also provides dimmable options.


The connection is very simple. Even better is that multiple lamps can be added in parallel. Note that you should only program the driver only on and off function in case the non-dimmable lamps are used. The non-dimmable has a symbol shown on the package or described on the datasheet of the lamp. For dimmable lamps, the driver can be programmed to perform on, off, and dimming functions. The dimming range is also depending on the lamp type and the user can adjust the driver to fit resulting in the best performance by using the ETS program.

Powerstar Technology Co., Ltd is a modern high-tech enterprise integrating R&D, design, production, sales, and service. We focus on high-end commercial lighting with strong innovation ability. Welcome to consult!

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