LED dimming

[RF Lighting]

Does anyone have experience of dimming LED?

I’m currently working to specify equipment for a job.

The client wishes to have approximately 36x recessed 600x600 LED tiles installed into a suspended ceiling grid divided over 3 circuits.

Due to the varied use of the space the lights need to be dimmable with a smooth dimmer curve for slow fades from 100% to 0%, and also have a steady flicker free output when set at a dimmed level such as 40% for example.

I’ve done quite a bit of reasearch and straight away standard triac dimming is a definite no no

It appears that I’ve really two options and that is either 0-10v / 1-10v control or DSI control.

I’m wondering if people have experience of either system and if so how were your experiences with either or both?

 

[oldbutnotdead]

Have a look at DMX controlled LED drivers (i have a link to some on the laptop but its elsewhere at the mo, try Google)- did a load of programming work at a club that was being re-opened, much to the new operator's surprise we found loads of dimmed 3 colour LED panels installed. DMX is an entertainment standard, these things dimmed smoothly from about 3%. Drivers all remote from the panels as well (much easier for maintenance).

 

[bernardgreen]

The way to achieve smooth flicker free and accurate control of the light output from LED lighting is to control the smooth DC current through the LED elements.

Any form of pulse width modulation to control the current can introduce non-linearity in the perceived level of dimming. The perceived non-linearity will vary from person to person.

Without smoothing to remove the pulsing the human eye will retain the brightness of the peak current pulse. The retain function varies from person to person so the dimming effect will to some extent be affected by the eyes of the people in that light.

 

[Gasguru]

AFAIR with at least 10 bit resolution and Gamma correction PWM is fine...have a listen to Mike Harrison on the Amp Hour and embedded.fm
RGBW is needed for better colour rendition and energy savings when only white is required.

 

[333rocky333]

We do a lot of stuff for Tesco and although they dont use them to dim across the range, they dim them down a few percent during the day to save energy and further dim at night hours, using a 2 wire Dali bus system linking the lights, to programmed Phillips lightmaster modular units.
In other areas like the old optical departments they were wired to what looked like a dimmer but included a sort of potentiometer adusting the 1-10 voltage.
Most of the stuff came from Dextra though not cheap.
https://www.dextragroup.co.uk/dextra-lighting/products/modled-slim/

They come in a range of dimming options, including Dali and 1-10 volt

 

[RF Lighting]

I’ve been speaking to the technical department at ansell and it’s looking like DSI is probably the best fit for us