Re: PPMC developments

[Jon Elson <jmelson-at-artsci.wustl.edu>]

Fred Proctor wrote:

> Jon Elson wrote about not being able to come out of estop:
>
> >
> For steppers, of course, there shouldn't be an amp fault input.  On my
> servo system, I also don't have individual amp fault signals.
> <
>
> Yes, but the code in emcmot.c calls the function that reports amp
> faults, and it should be coded always to return "no amp fault", which if
> it's zero corresponds to an ini file polarity of 0. This is part of the
> external interface dispatcher that you wrote for the PPMC:

OK, thanks for the clarification on how this is 'stubbed out' in versions
that don't need it.  In fact, i haven't attempted to use any of my code yet.

I'm just trying to get a baseline version to run with no external hardware,
then I'll try adding my hardware and software a little at a time.  I think I

have enough to chew on for a couple of days.

> I never thought about this, but it doesn't change the fault variable, so
> if this is uninitialized, your code will look at it unchanged and see a
> fault. That can be fixed in the .ini file, but I should have set *fault
> to zero just to be safe, e.g.,
>
> extern int extAmpFault(int axis, int * fault)
> {
>   *fault = 0; /* clear any "fault" */
>   return 0;
> }

Hmm, this may have something to do with odd problems where you can't
get out of estop with either polarity!

Jon