Sorry... I didnt write that question very well.
I wasnt looking for a definition of PLL, but more of an explanation of how it would be usefull in a CNC system. Ovbiously I'd prefer to buy the G320 because its quite a lot cheaper but if the G340 is a lot better then I'd be willing to spend the extra money for a better product. I suppose the question should have been, Do I really need the G340 or will the G320 do a good enough job ?. Does the G340 control the servo motors with greater precision, or am I missing the point completely ?
Regards
Dominic
http://www.ukrobotics.com