The touch-off is different as far as I've discovered so far. My min and max Z is -25 and +100 in the .ini file. If I move to what the machine thinks is 0 (wherever it was when the table booted up), and touch that off to say 40, then the machine will still only move -25 *from there*... so min would then be +15. What I want is to change the machine coordinates, telling EMC that the machine was not at zero on power up, and tell it where 0 is (which is what homing should do).
Thanks. On 4/12/2015 2:04 PM, Gene Heskett wrote: > > On Sunday 12 April 2015 11:07:41 Neil wrote: >> Another couple things I can't yet find... >> >> (1) How do I tell LinuxCNC that I am at a specific position. So I set >> Z to touch the top of a part and I want to tell it that's Z=-20. In >> Mach 3, I type the value in the DRO-displayed field. > To me, used to LinuxCNC, I'd call that a bit spooky. What we do is > highlight the dot for the axis, and click on "touch off" which will open > a small window allowing you to type a number into it. If you have > precisely enough located the top of the workpiece with a G38 command > I(see the fine manual again) and the machine is stopped at that contact > point, then it will be sufficient reference, so enter "-20.00000000" and > hit ENTER. The entry box will be closed and the Z position in the DRO > display will now show Z to be -20.00. > >> (2) Extra credit -- is there any way for me to set the Z-position to >> touch the top of a part (or table), then have one button set that to >> Z=-20, then it would automatically home X and Y? This would just make >> setup as simple as possible. > Someone more familiar may say it can be done, but I haven't found > anything in the docs that sound anything like that. > > But again, you are asking potentially deadly machinery to move, and I, > like most here, would discourage trying to do a one button solution for > 2, almost the same problems. IMO, zeroing the tool against the workpiece > is a valid operation, but when that is done. LCNC will force you to set > the home positions for every axis that is defined in the .ini file since > it will not do any other moves until it knows where it is. > > So the proceedure is > In the HOME_SEQUENCE, make z the last. Set its parking place at the > contact point of 0.000000. > > 1. home it all, by manually presetting it so Z is up in the air and will > clear everythingso as not to damage or demolish either the workpiece or > the machines tool as it moves to set the X and Y from each axis's own > home switch. Set the offsets in the .ini such that it is parked at the > center of the workpiece top when xy is done. > > Then, assuming the workpiece is isolated and the probe lead for G38 is > attached, a bit of magic logic in the .hal file will let you use the > probe contact as the z home function, but you will not be using the G38 > directly, you will be using that contact, crossfed into the homing logic > to find the top of the piece and thereby zero it there, and leave it > there. > > 2.When the homing is done, then click the z button, then the touch off > button, and enter your -20.0000000 offset there. You are, or should be > ready to load your code and hit the r button on the keyboard, it is all > ready to go. > > The excess precision is to keep math rounding errors to a bare minimum. > > If re-running the same code for multiple parts see the manual for how to > re-init all that stuff at matching zeros because the touch off entries > are cumulative, so the re-init of all available co-ordinate maps to > match the machine's zeros in the G53 map then puts you back to square > one every time. > > >> Cheers, >> -Neil. >> > HTH. > > Cheers, Gene Heskett ------------------------------------------------------------------------------ BPM Camp - Free Virtual Workshop May 6th at 10am PDT/1PM EDT Develop your own process in accordance with the BPMN 2 standard Learn Process modeling best practices with Bonita BPM through live exercises http://www.bonitasoft.com/be-part-of-it/events/bpm-camp-virtual- event?utm_ source=Sourceforge_BPM_Camp_5_6_15&utm_medium=email&utm_campaign=VA_SF _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
