Re: know your limits

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

Hi Bill,

I found my problem - the pre-made cable I was using to connect the computer
with the electronics box didn't have the relevant pins connected through -
dohhhh!!
So, this morning's job is to make a new cable and try again. As to switches,
I am initially using ordinary micro-switches, as you said, normally open for
home and normally closed for limits. When I get things going I may change
these for optical switches and gate them with the stepper signals. I had
worked out the series/parallel bit but, at the moment I only have one axis
running until I get the table back from the surface grinder.
Having said that, I am beginning to wonder what use home switches are and
how you use 'em. I had assumed that when you tell the machine to home its
axes they would all go to 000.000 which would then give a base for
programmed movement to begin. However, I now realise that none of the axes
finishes up at 000.000 as each has to move away to let the next one home (do
you have to actually home each axis separately or is there a command which
will send 'em all home at once?). So, when you have them all homed and then
offset to, say 0.1", does the program take this into account or do you have
to make a 0.1" allowance - I'm thinking here of running a second operation
program on a part machined part, i.e. part machine it then home the axes,
change tool and run a second program to work again on the same part.

Ian
--
Ian W. Wright
Sheffield  UK
www.iw63.freeserve.co.uk
----- Original Message -----
From: "William Scalione" <wscalione-at-nc.rr.com>

> I never did ask Ian which type of switches he was using, So Ian
> if you are reading this, normally open switches in parallel and
> normally closed switches in series.