Date: Mon, 29 Nov 2010 15:54:22 +0000 > From: andy pugh <bodge...@gmail.com> > Subject: Re: [Emc-users] Stepper Musings > To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > > On 29 November 2010 15:20, Belli Button <be...@iafrica.com> wrote: > > Unfortunately when a stepper looses synchronisation, one needs to 'stop' > the > > motor for the poles to realign and then you can move the motor again. ?I > > cannot see how a motor travelling at a velocity near its maximum capable > > velocity can loose just a single step with out stopping altogether. > > I think you are right about that, and tripping f-error is all you will > get there (which is better than nothing). > Where the scheme might work is in slow overload situations (I have > heard my lathe missing steps on very slow feeds when trying to push > too big a drill). In that case slowing the feed and recovering the > steps might work (in the case I mentioned the drill did keep feeding, > but the hole depth came out wrong and machine position was lost. >
At first I was not really big on this but the more I think about it, the more I like it. I play with small, benchtop size machines, where inexpensive steppers and drives generally work well and cost half or less of what servos would. A pseudo-servo mechanism that simply tripped a fault when something bad started to happen would provide most if not all of the benefit that true servos would, at much less cost. It's not magic and won't make the machine "more precise," but it would make it more fault-tolerant and that seems significant. It would also be a unique competitive edge that could bring a lot of users over to EMC2. Is this something that could be done just by wiring a few ~$50 encoders into a parport, or would you need more specialized IO hardware? ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
