On Nov 3, 2011, at 7:40 AM, andy pugh wrote: > On 3 November 2011 05:21, Tom Easterday <tom-...@bgp.nu> wrote: > >> Using gantrykins with a gantry that cannot be out of square more than about >> 3/4", how can we home the 2-jointed Y axis? > > I understand the question. I don't know the answer, and without a > 2-motor gantry with encoders, I can't experiment. I am not sure that > anybody has ever done it.
I am surprised that no one has done it, but perhaps you are right. > I assume that you have both joints set up with the same HOME_SEQUENCE > and with HOME_USE_INDEX = 1 for both sides? Yes, we have tried that. The problem is that the index pulses will be in different spots and so one side will find it's index while the other is still moving and hence racking occurs. > Do the encoder indices match? ie, with both encoders at the index, is > the gantry square? No. And I don't know how we would line them up. Also, if we were able to line them up, if the motor is ever disengaged from the rack we would have to re-align them. Sounds like it would be difficult. > What behaviour do you see when you attempt to home? What we need is to be able to home this axis in coordinated mode (where EMC moves the two joints in unison as Y axis) using only one of the two encoders. Thanks, -Tom ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
