Re: home and limit switch in series

[Ron Wickersham <rjw-at-alembic.com>]

another plug for sequential homing:

in the situation where you hit emergency stop while machining (due to tool
break or noting some error in the program) you would like (in the case of
a milling machine) for the z axis to home first to get the tool out of the
way before any movement in the x and y axes.   going sequential for x and
y would take longer than simultaneous homing but would be worth it for
many people to minimize the number of input lines.

-ron

Ron Wickersham
rjw-at-alembic.com
Alembic, Inc.

On Wed, 29 Mar 2000, Doug Fortune wrote:

---snip---

> Since it is nice to have one (or more) emergency stop buttons arrayed around
> the machine, my suggestion was to series wire it (them) with Home-Overtravel
> switches (ie overtravel switches only on the Home end) on every axis, coupled
> with a "try-to-home-each-axis-sequentially"  (ie non-simultaneously) algorithm
> to guarantee no indeterminate states during Homing.   That way you get a lot of
> use out of only one input line to the computer, including the emergency stop
> function.