You can HOME anywhere but typically Z0 is all the way up. If you don't have home switches then put some match marks on each axis and jog to line them up then home the axis. After you home you "touch off" to the material and you will be able to move within the soft limits of the machine. You can call the material Z anything you want.
JT On 4/12/2015 2:41 PM, Neil wrote: > 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 ------------------------------------------------------------------------------ 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
