Re: EMC Homing Switches

[Ray <rehenry-at-up.net>]

On Sat, 22 Jul 2000, Bill wrote:
> Ok I'm finally getting around to putting homing switches on my machine.
> Problem is
> the EMC web site shows only pin 12 for homing all 3 axis'. If 3 switches
> are all
> connected to pin 12 in parallel, and I home the X axis, how do I then
> home the
> other two axis'? Do I need to add a 3 position switch to connect proper
> switch
> to the homing input when I'm ready to home that axis?
> 
> Thanks, Bill
> scalione-at-netarrant.net

Bill

You are correct. about the nature of pin 12.  Only one switch connected to
it can be activated at a time.   These switches are expected to be
wired in parallel if you are using normally open switches and in series if
you are using normally closed. 

But the process of touching the switch and then moving the axis enough to
reset that switch can be set up in the ini file.  It's HOME_OFFSET and I
set mine to 0.1000.

What EMC does is watch for pin twelve to switch and then moves the
distance of the home_offset value and calls that home.  You will still
have to home each axis separately but home_offset will see to it that you
aren't sitting on a switch when you try to home the next one.

If you set up your home position using both a prox and the extra encoder
pulse, you would only have to move an axis far enough to get off that
encoder pulse.

Ray