know your limits

["Ian Wright" <Ian-at-iw63.freeserve.co.uk>]

Hi,

Having now got bits of mechanism moving back and forth under EMC control, I
am turning my attention to adding switches to the axes etc.

What use are home and limit switches using the EMC program? I can't work out
in my own mind how three home or limit switches in series can possibly give
any usable output. Presumably the first to trip will just bring the machine
to a complete stop and, since it would be physically impossible to get all
three to trip at the same instant, this would mean that two axes will be at
an unpredicatable position. If you use the 'home offset' feature, does this
mean that the first axis will close its switch, back off by the offset
amount and then stop, and that the second axis will then continue to move
until its switch closes and then back off and stop to allow the third to do
likewise? I had considered just relying on the software 'maximum distance'
option to limit travel but, if you reset zero along the way, this presumably
becomes ineffective. Any advice would be appreciated. Thanks,

Ian
--
Ian W. Wright
Sheffield  UK
www.iw63.freeserve.co.uk