Re: Re:EHP External Hardware Proposal

> From: Bertho Boman <boman@...>
>
> I think the issue here is stepper vs servo thinking.
>
> In the stepper case, the pulses typically are blindly put out by the software and it is assumed that the design is done
> correctly. The steppers will move as commanded and all is well.
>
> In a servo application the software "continuously" monitors the progress via encoder feedback and adjust the axis dynamically on
> the fly to guarantee the performance.
> Bertho
> ====================================
>
> > From: hansw <hansw@...>
> >
> > Hi Ian,
> > reply in text
> >
> > Ian Wright wrote:
> >
> > > From: "Ian Wright" <Ian@...>
> > >
> > > Hi,
> > >
> > > Ok, you've got me interested but there's one thing I can't quite understand
> > > yet - if you are using an external 'black box' to control the motors, where
> > > is the logic that controls the speeds of the various axes so that 1000
> > > assorted 'X' pulses plus 1000 assorted 'Y' pulses produces a perfect circle?
> > > As I see it now, EMC or its windoze equivalent does all the working out of
> > > pulse timing to ensure relevant positioning of the axes but, using an
> > > external box, this function would somehow be transferred outside the PC. For
> > > this to happen, the external box would seem to have to be intelligent enough
> > > to be able to work directly from something akin to a g-code file and, if so,
> > > what is the function of the PC in this now?
> >
> > As I see it, the PC will do the math, and send the data to the hardware, which will then control the motors.
> >
> > > Is it just a storage device and
> > > is the external hardware really just a kind of stripped down version of a
> > > completely stand-alone machine controller?
> > >
> >
> > No it will still be busy doing the math and keeping track of the external hardware's progress...
> >
> > No details yet, I have a few ideas about the whole handshaking and data transfer operation... The is also confusion about
> > stepper and servo...
> > Some people are wanting a "do it all" device. Myself I just want to control steppers.
> >
> > hansw
>
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