Well, first you'd need to make sure you have two separate accounts for it. Unless something has changed, attempting to log into the same data center with one version, that the other is logged in on gets the "A character is already logged in" error. So, adding pc to the account wont work. You can log in to separate data centers without any issue. For instance, I can log into a character on Gungir (JP) and Excalibur (NA) at the same time, one on ps3, one on pc. But not on, say, Faerie (NA) and Excalibur