Re: EMC signal output

Cryo,

While I don't know what type of machine you have either; I would say
that it would be unusual in my experience to need the type of
direction pulse you have drawn. I would have answered very much the
same as Jon, (if he hadn't already done so). Most drives want the dir
bit "set before" and "held after" the step bit transition. It is VERY
unusual to need a "reset" of the dir bit.

Because of this, I would say you are probably looking at some "c"
programming.

You mention that "as far as you know, you need this type" of dir bit
pattern. Could you tell us why/ where this became evident?

Please understand that I am NOT challenging you! I am just curious
which type of control/driver needs this to add to my knowledge...

Thank you in advance.

Ballendo

P.S. The step rate generator Jon mentions is a hardware product he is
developing for emc(and others???). In a previous post, he mentioned
having some preliminary production boards available in July...

--- In CAD_CAM_EDM_DRO@y..., Cryo <cryo@n...> wrote:
> Hello Jon,
>
> How do you know what kind of machine I have ?
>
> As far as I know I need a pulse like that and now I need to know how
> to do that. Do I have to write some C-code or is there any settings
on
> that?
>
> You mentioned your "step rate generator". Where I can get that, if I
> can get that?
>
> --
> Cryo - Cryo@n...
>
> --- Original Message ---
> JE> Cryo wrote:
>
> >> I didn't find any documentation about EMC's port settings.
> >> Can I change step/dir signal polarity easily somewhere?
> >> My driver needs signal which is normally down and when step coms
is
> >> up.
> >>
> >> Another thing is timing. Can I change pulse width and other that
kind
> >> of stuff somewhere?
> >> I need signal which is like this:
> >>
> >> step |---| |---|
> >> ----| |-------| |----
> >>
> >> dir |-------| |-------|
> >> ---| |---| |-
> >>
> >> I put oscilloscope to EMC output and it's like:
> >>
> >> step |---| |---|
> >> ----| |----| |----
> >>
> >> dir |------------|
> >> ----| |----
> >>
>
> JE> I don't see the problem here. It should be legal for the
direction
> JE> signal to stay at the same polarity if two consecutive steps
will be in
> JE> the same direction. The only concern is that the direction
signal does not
> JE> change too close to the active edge of the step signal (which
can be the
> JE> rising or falling edge, depending on the step driver).
>
> JE> The polarity of the step signal is also not generally
important, except
> JE> for the relationship to changes in the direction not ocurring
too close
> JE> to the active transition.
>
> JE> My parallel port step rate generator does allow the width of
the step
> JE> pulse, as well as the setup time delays around the active edge
of the step
> JE> signal to be controlled. I will probably put polarity
switching logic
> JE> in the final version of this.
>
> JE> Jon
>
>
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