[SOVLED] How to convert 3 dimmers RGB to colorpicker?

Can you be a little more specific with your question please ?

items:

Dimmer fix1r "Fixture 1 red   [%.0f]" (gStreetDMX_GR1_r){ channel="modbus:data:beckhoff:DMXstreetlamps1_123:fix1r:dimmer" } 
Dimmer fix1g "Fixture 1 green [%.0f]" (gStreetDMX_GR1_g){ channel="modbus:data:beckhoff:DMXstreetlamps1_123:fix1g:dimmer" }
Dimmer fix1b "Fixture 1 blue  [%.0f]" (gStreetDMX_GR1_b){ channel="modbus:data:beckhoff:DMXstreetlamps1_123:fix1b:dimmer" }

Three dimmers: R, G, B

On your phisical device 4 channels?
How to manage color through color channel if I have 3 dimmers?
Through rules?

Didn’t we already go through this for your KNX RGB device?

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Does this mean that we can’t do this without rules?

Depends what you mean by “this”.

But nothing has changed in openHAB since last time. Color is held internally in openHAB as HSB, if you want to convert to three separate RGB values then you have to do work.

I mean, maybe in this binding the color itself translates the values to 3 dimmers and back

You’re talking about the Modbus binding now?
No, there is no way to do that.

You could write three different transformation scripts to select the R or G or B parts of a Color type Item. Then link one Item to three different Modbus data Things targeting different registers, each Thing using a different write transform script.

But it would be a bit pointless, because there is no way to combine incoming data from three different Modbus data Things without using rules.

Are you paying a lot for rules, what is the objection here?

The DMX binding does convert the Color channel into the 3 individual channels

No, not modbus binding.
DMX binding.
Yes. I paying a lot for rules.
82 fixtures for 3 channels (RGB).
My powerfull server (24 cores) without rules hard to cope with managing a group of 82*3=246 items.
(Items to modbus tcp)

Okay. The Items you asked about use the Modbus binding, not DMX binding. Try to provide examples related to your questions.

People run openHAB on Raspberry Pi, you probably ought to look into why your system performs so poorly.
You mention a fair sized Modbus configuration, which certainly can make an impact on performance if you do not take care.

In case anyone wants to do this with Velbus, I have an RGBW ledstrip, with a VMB4RYNO, a VMB4DC and 2 VMB2LEDDC
And managed to make this work thanks to @rossko57 and @Bagunda