its a very tricky question to answer as depends how dynamic you want or need it.
we used a standard Hz mode VFD to control a CNC spindle motor as Flux Vector has a limit of 4000rpm on our VFD so had to use Hz mode to get to 6000+ can check out afew vids here poke around on my other vids too http://www.youtube.com/watch?v=D6dGYsXAPIU Control Techneques, Yaskawa etc all do high level VFDs todo just what you have asked some/most vfd only do it to 1 postion on the encoder feedback, others you can control over postiion (be it analog or other) but i think it also depends a grate deal on the motor type. like new CNC spindles that do C axis etc i see there motors listed as AC Spindle Servos induction motors but with Servo like response at zero & low speeds. but i know alot of new CNC. maybe someone that knows abit more tech ins and outs can answer abit more detail whats realy going on between spindle motor and drives these days? rob ------------------------------------------------------------------------------ What You Don't Know About Data Connectivity CAN Hurt You This paper provides an overview of data connectivity, details its effect on application quality, and explores various alternative solutions. http://p.sf.net/sfu/progress-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users