----- Original Message ----- From: "Chris Radek" <ch...@timeguy.com> <snip> > I admit that I don't quite see how these tool changers are supposed to > work. When the stepper backs up against the stop, doesn't it stall > and lose position? Is there some kind of feedback available? When > you start up, how do you know what position it's in? > > I have never seen a machine with a tool changer that operates like > this. > Boxford in UK used this for small and medium sized changers.
For an 8 position turret you have a ratchet with 8 teeth and a spring-loaded pawl. Assuming you know where you are now (say tool 2) and each click needs 100 steps. To move to tool 5 you output 330 steps. You now know that ratchet is about 30 steps after a "click". Send 40 reverse steps. The stepper stalls, as you say, but you are in the known position for tool 5. Next move to say tool 6 just outputs 130 steps forward and 40 back. John Prentice ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
