Re: EMC - M codes pause motion?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

>
>
> foxprints2003 wrote:
>
> >In EMC m-codes cause the interpreter to pause motion, example:
> >
> >g02x30y30i30j0f300
> >g02x0y0i0j-30m7(or m8,m3,m4 etc.)
> >EMC executes 1 quadrant arc, pauses motion, turns on M code

output,

> >resumes motion to complete arc.
> >If the M code is removed the motion is executed seamlessly.
> >
> >I need to be able to turn outputs on/off on-the-fly, Is it

possible

> >to setup EMC to allow M code output on-the-fly?
> >
> >
> M03, M04 and M05 are spindle start and stop commands, and there is
> a built-in delay (specified in the .ini file) that stops activity
> waiting for
> the spindle to come up to speed, or brake to a stop. It makes

perfect

> sense in machine tool applications to have a delay here. Reducing

the

> delay specified in the .ini file should make it shorter, but I

don't know

> how short it can be.
>
> M07, M08 andd M09 are coolant on/off commands, and it seems

reasonable

> that a delay is not always needed there. I think the problem may

be

> related to
> the fact that the auxilliary I/O is handled in the Linux part of

EMC, while

> motion is done by the real-time part. I suspect that the pause is

when

> these
> two parts are synchronizing for these operations.
>
> Jon

This must be done by the interpreter because the pause is not due to
lack of processing speed, the system decelerates to a stop turns on
the output immediately after stopping & then accelerates back into
the next move. Clearly the system planned the stop due to the m code
insertion. I can't imagine turning on a single discrete output would
require nearly as much processing time as anything else.
-Dean