Hi Edgar,
it is a little more complicated with your fixture - because it has 1 master intensity for 4 pixels.
I suggest you use a 2x2 RGB fixture and patch it always on the second DMX address of the fixture and use a 1 pixel intensity fixture that you always patch on the first address of the fixture.
So you have 2 fixtures in pixelmad for one (4 pixel) fixture in real world.
If you like to go a step ahead you might want to write your own fixture for the intensity channel - setting it to a fixed value <fixed output="255"> or linking it to the master intensity <output="MASTER_INT">
Olli
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Oliver Ranft, Aachen, Germany