On Mon, Jun 30, 2014, at 10:54 AM, Gene Heskett wrote:
> On Monday 30 June 2014 08:58:16 John Thornton did opine
> And Gene did reply:
> > If you wire them separately then in Axis you can only jog in the
> > correct direction to jog off of the limit switch.
> > 
> > JT
> 
> They are wired separately John, using parport pins 10 and 11 netted to the 
> correct axis, but one is "neg" and one is "pos", but the trip of either 
> disables everything, raising the 2nd "enable" button, and I must check the 
> ignore limits box, then re-enable before I can jog off.  Once it is out of 
> limit trip, the icon |< indicating which adjacent to that axis's DRO goes 
> away, and the ignore limits checkbox is cleared.
> 
> It does indicate which "joint" by that means, and in the advisory pop-up 
> in the lower right corner of its screen.
> 
> Do I need some other option set in the ini file to allow this? This is 
> LCNC 2.5.4-28-gea8e59a.

On a two-axis machine with a switch at each end of each axis you have
four switches.

If you use four hardware inputs, then each switch can be individually
routed thru HAL back to the corresponding motion HAL pin, and LCNC
knows exactly what happened when you hit a switch - which axis and
which end.  Since it knows which end, it lets you back off.

If you have only two hardware inputs, you have two choices:

1) You can connect both end switches for X to one input, and both ends
of Z to the other.  The first hardware input gets routed to both X-neg
and X-pos in HAL, and the second one goes to both Z-neg and Z-pos.
Since both pos and neg motion pins go true when you hit either
switch, LCNC doesn't know which end you hit.  So you have to use
the ignore limits box to jog off.  But you do know which axis it was.

2) You can connect the Z-neg and X-neg switches to one hardware
input and the Z-pos and X-pos to the other.  In HAL, the first input
is routed to motion-Z-neg and X-neg, likewise with the positive.
In this case, LCNC can't tell which axis hit the limit, but it does know
which end, so it can allow you to jog off without using the ignore
limits button.

If you only have one hardware input, then of course you need to tie
all four switches together, and LCNC can't tell which end or which
axis is on limit.

In your case, you need to choose between option 1 and 2 above.
Since you say it knows which axis is on limit, it sounds like you
chose option 1.

You can change your mind if you like option 2 better.

John Kasunich

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