if you setup dmx to be 1st dmx universe off of a pixelnet hub, and had an express on it set to start with dmx channel 1. and also.... had a ssc running on that same same hub set to pixelnet channel 1....
in vixen, channel 1 would be the first channel on the express AND the Red value on the first pixelnet node.
channel 2 would be the 2nd channel on the express, AND the Green value on the first pixelnet node.
channel 3 would be the 3rd channel on the express, AND the Blue value on the first pixelnet node.
channel 4 would be the 4th channel on the express, AND the Red value on the second pixelnet node.
etc.
etc.