Tunable White RDM fixture

[Drosselmeier]

Hi all.

We are trying to develop lighting fixtures with tunable white. So, there are 2 possible notations to control them:
1-st notation: (GENERAL_INTENSITY; CCT), where CCT=Correlate Color Temp, K
2-nd notation: (W_INTENSITY; C_INTENSITY), where W and C = Warm and Cool components.

At 1-st notation there are 2 options:
- Set CCT via RDM (using specific PID for CCT) this case a fixture is usual DMX with footprint=1
- Set both CCT and GENERAL_INTENSITY via DMX, this case footprint = 2.
Which approach is correct?

At 2-nd notation footprint also = 2. If we control W_INTENSITY; C_INTENSITY via DMX, shoul I describe them the SUPPORTED_PARAMETERS? In the same way, for RGBW color fixture we don't specify R G B W color components as PID.

Thank you.

[ericthegeek]

There's no single correct way to do it.

In general, Null Startcode is intended for Control, and RDM is intended for management, but those can cross-over for something like color temperature.

If this were my fixture, I would likely have 5+ personalities:
1: A 2-slot personality with Intensity and CCT
2; A 2-slot personality with W_Intensity and C_Intensity
3: A 1-slot personality with fixed 2700K CCT
4: A 1-slot personality with fixed 3200K CCT
5: A 1-slot personality with fixed 5500K CCT

You can keep adding 1-slot personalities to get the CCTs that make sense for your market.

Another possibility is to keep personalities 1 and 2 from my list above, then define a third personality with 1-slot and use a manufacturer specific PID to set the CCT.

Either approach is fine.


If you use W_INTENSITY and C_INTENSITY, then those two values would be sent as DMX Slots, not RDM PIDs. If you want to describe those slots via RDM you would use SLOT_INFO, SLOT_DESCRIPTION, and DEFAULT_SLOT_VALUE.


Footnote: You may also need 16-bit versions of some of the personalities depending on how your dimming engine works.

[Drosselmeier]

Dear ericthegeek,

thank you very much for detailed explanation.
This one looks like the best solution:
============
Another possibility is to keep personalities 1 and 2 from my list above, then define a third personality with 1-slot and use a manufacturer specific PID to set the CCT.
============
And fully meet the paradigm - DMX for control, RDM for configuration.