On Sun, 23 May 2021 at 03:31, Jon Elson <el...@pico-systems.com> wrote:
> On 05/22/2021 07:12 PM, dave engvall wrote: > > > >> Has anyone tried homing off the reference channel on a > >> glass scale? There is information on the web indicating > >> that at least some of the chinese glass > >> scales mask and compare the 4 lines each side of the > >> reference mark in addition to the reference. This might > >> imply that the usual homing routine would work. > >> I haven't tried this only because I have nothing running > >> at the moment capable of doing this. > If the "reference channel" produces one pulse at a specific > spot on the scale with no other pulses within a few tenths > of an inch, you should be able to use it for precise > homing. You'd have a limit switch that would begin the > search for index sequence of the homing routine. Then, it > would advance until it saw the pulse from the scale. Just > like the Z mark on a rotary encoder. > > Jon > > I often feel like that I live in a world where cars have three wheels, and no-one wants to believe that 4 wheels are better.. So.... I don't understand why the reference strip in an encoder isn't half black, half clear, along the full length. Now; - there is only a single transition that marks the reference point - it's always obvious which way to go to find that transition; 0:go left 1:go right - you don't have to worry (as much) about missing that obscure 'pulse' - it will remove the homing dilemma plaguing machinists all over the world What am I missing here? Roland _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
