EMC Home and Limit Wiring

I have some questions about the Home and Limit switch wiring for EMC. (
I'm a CNCPro user )

From what documentation I can find, it seems that three switches are
envisioned for any single axis; one for Home, one for "Near" Limit and
one for "Far" limit.

In the case of a three axis system, then, it looks like nine switches
are expected.

It also appears as if the switches are designated for a series
connection .. a Home loop, and two Limit loops.

I GUESS I can understand how this might work when the HOME setting is
asked for.

Move X only until HOME is triggered, then back a bit until it's not
triggered.

Move Y only until HOME is triggered, then ...

Move Z only ...

But I don't understand the logic behind the -Limit and +Limit. Why
should EMC care WHICH direction things are going when a Limit switch is
activated. Just stop !

And finally, is there no provision for an EStop switch ? Or is this a
double-pole switch to be added to both Limit switch loops.

Not clear on the concept - any thoughts appreciated.

Alan

--

Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta