Just as a random data point in all this, I have a little 7x toy lathe currently running with Mach2 that I'm getting ready to switch over to EMC. It homes using a single snap-action microswitch, the kind with no lever. I don't know if this is different from EMC, but Mach homes by backing in until the signal changes, and then driving back out until it flips back. I don't know if this technique is based on the typical microswitch being more consistent in one direction than another.
Anyway, I went down tonight and put a .0005" indicator on and homed it a few times to see what happened. The needle snapped back to precisely the center of the 0 line every time. I imagine it's possible that the zero point will drift over time as the mechanism ages, but these things are rated for tens of thousands of actuations so probably not too fast. For those of us not requiring bulletproof repeatability on a machine that runs all day, this seems like a very simple setup compared to a dual-switch system. On Thu, Dec 2, 2010 at 10:35 AM, <sa...@empirescreen.com> wrote: > As I mentioned before - We home using 2 micro switches. one switch is on > the linear slide and one is on the timing gear. > > http://www.electronicsam.com/images/KandT/homesw.jpeg > > the 2 switches are hooked in series. so when the linear closes then it > waits for the one on the timing gear to close. then it does the homing > dance. :) I would think you could do the same thing (in hal) with the index > pulse - just go slow enough that you won't miss it. (I do the same thing) > > sam > > > On Thu, 2 Dec 2010 15:23:05 +0000 > andy pugh <bodge...@gmail.com> wrote: > > On 2 December 2010 15:08, Tom Easterday <tom-...@bgp.nu> wrote: > > > perhaps makes me surprised that the EMC user base is just homing > inaccurately and warm and fuzzy in their ignorance. > > > > There may be a bit of that. I know that it would be nice if my lathe > > held diameter to better than 0.1mm through a restart, but I just > > accept I need to measure diameter at some point and re-touch-off. > > > > -- > > atp > > "Torque wrenches are for the obedience of fools and the guidance of wise > men" > > ------------------------------------------------------------------------------ What happens now with your Lotus Notes apps - do you make another costly upgrade, or settle for being marooned without product support? Time to move off Lotus Notes and onto the cloud with Force.com, apps are easier to build, use, and manage than apps on traditional platforms. Sign up for the Lotus Notes Migration Kit to learn more. http://p.sf.net/sfu/salesforce-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
