I think it is required that you feed the actual CSMIO from one supply and the I/O from another if you want to keep the opto isolation, could be wrong though but I am sure I read that in the manual.
On the Chiron I have a big 3 phase supply but it has 2 output channels that are not connected so I used that. On the plasma I got a couple of power supplies, one just for CSMIO, Enc and MPG modules power side and a bigger one for all the rest of the 24v (limits, MiniTHC, servo drives logic etc)
I got the ones on the plasma from Eastern Transformers, bought a few of each 100w and 10w as the price was good and I like to have spares.
Looks like I bought the last of them as they only have 5w ones left.
http://www.ete.co.uk/pss-ip20-miniature-series-5w-to-300w--93.htmlHood