The Diagnostic parameters are completely defined by the machine tool builder. With a Series 0 CNC, they begin at address 300 and go up from there. They may consist of Timers, Counters, and Keep Relays. Since the assignment of them is up to the MTB, you won't find any definitions of them in the FANUC manuals. You'll have to consult the MTB documentation or try contacting the MTB or distributor for information.