Hopefully this information will help. I've homed my knee mill. The limit switches are also used as the home switches. The knee is all the way down when homed since that's the safest place to go. Table has moved to the far right and as close as possible to the frame. https://autoartisans.com/mill/Mill_Homed_s.jpg
The next photo shows the machine coordinates as 0,0,0 when homed which is where the spindle is. https://autoartisans.com/mill/Mill_MachineCo_ord_s.jpg The final photo shows the machine coordinates with table all the way forward which duplicates Cartesian Y as Y gets bigger as the spindle is moved up the graph. X position gets bigger as you move to the right on the graph or as the spindle is in effect moved to the right. The Z value is negative because in effect we are moving down below the zero plane even though it's the knee that is moving up. The value of Z is based on the quill touching a 1-2-3 block set up for 3". That shows the absolute total distance from the home position to the bottom of the quill is 9.725"+3"=12.725" https://autoartisans.com/mill/Mill_At_Limits.jpg In the HAL file the limit switches are defines as follows: # MESA 7i92H P2 connections net min-home-x <= hm2_7i92.0.gpio.014.in net min-home-y <= hm2_7i92.0.gpio.015.in net max-home-z <= hm2_7i92.0.gpio.016.in net max-x-y-min-z <= hm2_7i92.0.gpio.003.in Notice the Z axis switches are at the other end of the XYZ co-ordinate system and the non-home limit switches are in series so any one closure will cause a motion stoppage on all axis. Further in the HAL file I have: net min-home-x => joint.0.home-sw-in net min-home-x => joint.0.neg-lim-sw-in net max-x-y-min-z => joint.0.pos-lim-sw-in net min-home-y => joint.1.home-sw-in net min-home-y => joint.1.neg-lim-sw-in net max-x-y-min-z => joint.1.pos-lim-sw-in net max-home-z => joint.2.home-sw-in net max-x-y-min-z => joint.2.neg-lim-sw-in net max-home-z => joint.2.pos-lim-sw-in Cheers, John Dammeyer > -----Original Message----- > From: Stuart Stevenson [mailto:[email protected]] > Sent: April 3, 2026 8:50 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] y axis homes wrong direction > > I always configured my machines with machine zero at the most positive > position Ie > facing the machine > tool position not table position > X as far right as it will go > Y as far away as it will go > Z as far up as it will go > > two reasons, all the WPC offsets were always negative. > zero return is always in the same direction > Therefore, I didn't have to 'thnk' (remember) "Which way did I configure > this machine?" > > I did this no matter the control manufacturer. Outside service men were > sometimes confused but operators quickly adjusted. > > regards > Stuart > > On Thu, Apr 2, 2026 at 6:48�PM Luca Toniolo <[email protected]> wrote: > > > I'm sorry, I just saw what he wrote, Z homes at 4 is wrong, Z should home > > at 0, and Z works in negative, this is pretty standard, you'll have a lot > > of headaches if you don't do it that way. > > > > On April 3, 2026 7:31:39 AM GMT+08:00, andy pugh > <[email protected]> > > wrote: > > >On Thu, 2 Apr 2026 at 23:49, Luca Toniolo <[email protected]> wrote: > > >> > > >> If your Y plus is toward the back of the machine, and your homing > > sensor is toward the back of the machine, you home at 30 not at 0. > > > > > >It's often better to home to 0 and set the lower limit negative. > > >LinuxCNC works equally well either way, but some CAM systems make > > >assumptions. > > >Admittedly generally with Z. (Fusion 360 CAM will often insert a G53 > > >Z0 as a full retract). > > > > > >You need to work out if the axis is reversed entirely, or just the > > >homing direction. > > > > > >The solution might be as simple as specifying negative > > HOME_SEARCH_VELOCITY > > > > > >-- > > >atp > > >"A motorcycle is a bicycle with a pandemonium attachment and is > > >designed for the especial use of mechanical geniuses, daredevils and > > >lunatics." > > >� George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > > > >_______________________________________________ > > >Emc-users mailing list > > >[email protected] > > >https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > Addressee is the intended audience. > If you are not the addressee then my consent is not given for you to read > this email furthermore it is my wish you would close this without saving or > reading, and cease and desist from saving or opening my private > correspondence. > Thank you for honoring my wish. > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
