On Tuesday 16 April 2013 20:16:45 SourceForge.net did opine: > Bugs item #3604558, was opened at 2013-02-13 10:45 > Message generated for change (Comment added) made by jeromepilot22 > You can respond by visiting: > https://sourceforge.net/tracker/?func=detail&atid=106744&aid=3604558&gro > up_id=6744 > > Please note that this message will contain a full copy of the comment > thread, including the initial issue submission, for this request, > not just the latest update. > Category: G-code Interpreter > Group: None > Status: Open > Resolution: None > Priority: 5 > Private: No > Submitted By: JeromePilot (jeromepilot22) > Assigned to: Nobody/Anonymous (nobody) > Summary: probe trips message while G38.2 or G38.3 > > Initial Comment: > With 2.5.1, with 2 different controlers , I want to use the G38.2 or the > G38.3 G-code to set the zero of my machines. The movement and touching > detection is OK BUT I have sometime (more than 50%) an error message > just when contacts saying me that the probe trips during a non-probe > MDI command. But the G38 is a probe MDI command I think ?!?? I don't know about the MDI, but I use the command to locate work fairly often, and have noted that I must keep the backlash setting at some value that just exceeds the actual. I appears to me that when you double up the G38, once fast, once slow, backing away 2 or 3 thou in between, that a contact make or break during the backlash move is ignored, so this requires a backlash setting sufficient to break the contact during the backlash move. An extra .0002" in the axis backlash setting seems to reduce that noise to just a very occasional occurrence instead of almost every time. YMMV, but thats what I sort of read between the lines.
I also have a .1 capacitor on that line so the rise time at break is slowed, and so that a momentary contact is held long enough for linuxcnc to recognize it. I often probe with the cutting tool, turning backwards when looking for an edge, fast enough that combined with the hold the capacitor gives, say 200 rpm in reverse, so the tool effectively represents a cylinder of that diameter. With the tool blown clean, the repeatability is in the .0002" range with my old worn conventional acme screws. Not perfect of course, but then I'm not grinding a new mirror for the Hubble either. :) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Murphy's Law is recursive. Washing your car to make it rain doesn't work. A pen in the hand of this president is far more dangerous than a gun in the hands of 200 million law-abiding citizens. ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
