I dont know how this is done on newer lathes but Ive seen older ones with an electric clutch on the spindle that engages and a seperate servo motor that does the milling or positioning moves then disenguages for normal lathe turing. Could an encoder be put on a the servo(except for the index pulse) this way the servo encoder would not have the wrap up from turning operations as it would be disengaged most of the time? I am sorry that this is probably not helping this person but I am thinking about doing this to a lathe of mine and this topic reminded me of my question
Terry ----- Original Message ----- From: Jon Elson <el...@pico-systems.com> To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Cc: Sent: Wednesday, July 4, 2012 3:00 PM Subject: Re: [Emc-users] A axis and spindle andy pugh wrote: > The behaviour would then be that the axis would move in A-word control > until an M3 or M4, at which point the mux would direct the speed PID > to the PWM generator. On M5 the mux would switch to the old A-axis > position control, the oneshot would trigger, loading a "true" to the > encoder.N.index-enable pin. Because the spindle is many turns away > from it's required position the A-axis PID controller will be maxed > out, so the spindle will do at least one turn past the index. When it > passes the index the encoder counts will go to zero, the PID will no > longer be saturated, and the spindle should return to the last > commanded angular position. > > And, how to do this without causing a momentary huge following error that either causes a following error abort or a servo amp trip is not clear. I think it needs some kind of gradual gain change to allow the servo to catch up gradually before going to full gain. Jon ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
