On Sunday 28 February 2021 23:21:12 Feral Engineer wrote: > Hello Hive mind, > > Question for the group. I have an emco pc turn 55. I've successfully > gotten everything working 100% on LCNC with the exception of one > thing, the x and z axis utilize a mechanical limit switch to latch > home position, but then each axis has a pnp proximity sensor that > triggers the actual home position on a 1 ppr encoder of sorts. I've > just been using the mechanical switches, but I'd like to try and get > the proximity sensors working during the home sequence. > > Any suggestions on where to start getting this to work?
Depending on your preference I would wire separately if you've the inputs to spare. But combine them in a mux2 module such that the both have to be true (or go true in sequence) for your version of true so that when the switch closes, it backs up, slowly to find the proximity closure. You can search for the switch fairly fast, but if the proximity is a rotating shaft, you might go by it and miss it if you do not have a base thread. I'd have two signal wires from each axis, rigged so the normal "home" is that axis's switch, until it closes, and use the dir signal to switch a mux2, so it is then looking for the proximity switch on the "home" signal line back to motion. I have found normal far eastern micro switches are actually pretty consistent, fraction of a thou repeatable. In one case I used a micro sized pushbutton mounted of a leaf of hard alu about 3/4" long for the y home on my 6040, using the springiness of the alu as its lifted from solid contact with the frame as the edge of the gantry slams into it at around 60 ipm. Thinking I might trap debris under the "spring" but that has not occurred in 2 years. Checked with a .0001 dial, home is within .0002" every time. But without a base thread, the second search speed is set quite low since you only get a chance to sense it at millisecond intervals in the servo thread. If using such logic, be sure the addf's are in fall thru in the same invocation order. > Thanks in advance > > Phil > The Feral Engineer > > Check out my LinuxCNC tutorials, machine builds and other antics at > www.youtube.com/c/theferalengineer > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
