Why not do the same thing for "free" with a g-code processor that sets all Z coordinates to some constant. No hardware required, just a few lines of Python or whatever you like.
On Wed, Aug 8, 2018 at 2:21 AM andy pugh <[email protected]> wrote: > On 8 August 2018 at 03:17, Brent Loschen <[email protected]> wrote: > > > And now for my question. The old Bridgeport had a button on the front > panel > > titled "No Z" that turned off all z motion and let me "air mill" a part > as a > > sanity check of my X & Y boundaries/fixtures. I can't find the > equivalent > > functionality in LCNC and was wondering if anyone here has done this, or > > knows the best way to implement it. > > I suspect this would start off looking easy and turn out to be > surprisingly difficult. > > Turning off the Z is pretty easy, you would disable the Z stepgen and > (at the same time) connect joint.2.motor-pos-fb to > joint,2,motor-pos-cmd rather than to hm2_5i25.0.stepgen.2.position-fb. > > Now the machine thinks that Z is moving, so it is happy, and the > stepgen is disabled, so no steps are sent. That just needs a mux2 > component in the HAL. > > But what happens when you release the button? Suddenly the machine > will realise that the Z axis is not where you told it it was, and you > will get an immediate following error. Also, the Z will attempt to > move to the "real" position at a speed only limited by the stepgen > accel and velocity limits. > > So you probably need some Hal-trickery to gently move the Z back in to > commanded position, while at the same time lying about the position to > prevent following error being triggered. > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1916 > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
