My mental picture of your machine might not be accurate. I'm visualizing a cutting head that moves along an axis using one motor, and another motor that moves the entire axis. If that is wrong then the rest is wrong too.
Anyway, assume that home = 0, and when homed the cutter head is at the far left end of the "movable axis", and the moveable axis is also at the far left end of the machine frame. If you then command 500mm, the movable axis moves 250mm to the right, and the head moves 250mm to the right relative to the moveable axis. That means the net movement of the head is 500mm. If my mental picture is wrong, can you correct it? Maybe with a real picture or a sketch or something? John Kasunich On Tue, Nov 17, 2015, at 01:17 PM, Marius Liebenberg wrote: > That will work if you always have tubes that are longer than 3000mm. If > you need to cut shorter that half the distance then only one motor will > move and then the scale will be broken. This is way I thought that some > hand-off might be the answer. > Or am I not seeing the whole picture with the two steppers moving > together but always in opposite directions? > > Would this mean that the zero position will have both motors sitting in > the middle? > > ------ Original Message ------ > From: "John Kasunich" <jmkasun...@fastmail.fm> > To: emc-users@lists.sourceforge.net > Sent: 2015-11-17 20:04:56 > Subject: Re: [Emc-users] Split X axis - How to go about that? > > >Instead of a hand-off you could run both axes all the time. If you > >command a 100mm move, > >the main axis would move 50mm and the auxiliary axis would also move > >50mm. > > > >To do that with steppers you could simply send the same step pulses to > >both motors (if they > >have the same steps-per-mm). Then tell LinuxCNC that the steps-per-mm > >is half of the > >value for each motor. > > > >Homing might be a challenge. You would like the home switch for each > >axis to cut off > >the step pulses for that axis, and not tell LinuxCNC that the switch > >has been hit until > >the machine actually hits both switches. HAL can do that if you are > >doing software > >stepping. > > > > > > > >On Tue, Nov 17, 2015, at 12:51 PM, Marius Liebenberg wrote: > >> That will work for servos but in my case I am using steppers. Not > >>sure > >> if the problem is the same. I want the axis to be spit in two and the > >> controller must know when to use what stepper to get all the way from > >>0 > >> to 6000mm. Somewhere in the middle there must be some sort of > >>handover > >> between the two steppers. > >> > >> > >> : > >> > > >> >> has anyone attempted this kind of silly > >> >> arrangement? > >> > > >> > >> >https://forum.linuxcnc.org/forum/46-francais/28479-cinematique-avec-axes-redondants-presentation?limitstart=0#52533 > >> > > >> > > >> >-- > >> >atp > >> >If you can't fix it, you don't own it. > >> >http://www.ifixit.com/Manifesto > >> > >>------------------------------------------------------------------------------ > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > >-- > > John Kasunich > > jmkasun...@fastmail.fm > > > >------------------------------------------------------------------------------ > >_______________________________________________ > >Emc-users mailing list > >Emc-users@lists.sourceforge.net > >https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
