Re: [CAD_CAM_EDM_DRO] Threading on a lathe with EMC

Hi Chris

There are two places where the code can be inserted.

1) Hard coded in to the low level motion control module operating in realtime.

2) In the trajectory planner running in user space.

Both have advantages and disadvantages. There are also questions regarding
the spindle encoder counter - Should it roll over to zero at each index,
should it be an absolute count or signed....
What is the best stratagy for the threading - Alternate flanks cut on each
pass, or just plung in and hope for the best....

Perhaps we should take this discussion over to the EMC list and debate the
finer details there.

One last thing - Don't be afraid to modify/hack/butcher the code. If you do
break it in a major way, we can always use the cvs history to go back a step.
Even if you did manage to break the sources, no one is going to hunt you down
for it. It has taken me a long while to pluck up courage to mess with some
of the core files, and I'm still here. As long as any changes are documented,
who is going to complain..

Regards, Paul.

On Monday 29 October 2001 10:07 pm, ccs@... wrote:

> Paul, from my reading of the code I think the major challenge is
> figuring out where "reactive" thread synchronization should be
> implemented. Once it's clear what component to modify, it's 'simply' a
> task of doing it and testing;-) But as the modifications are so
> fundamental, I've hesitated to jump in and try may hand at it when
> others may have more insight into where the changes are best made
> to keep in the spirit of the original architecture.
>
> "Proactive" threading with a servoed spindle is of course much simpler
> software wise but requires more equipment on the machine, which makes
> it less usefull to the average hobbyist. Software only has to be
> written once - hardware has to be duplicated on every machine.
>
> Chris