Re: PC board designers.... Spindle Speeds...

Sorry, let me revise that....
Brakes (auto-brake) are usually switched elecrically by engaging
when there's no power to the spindle mag'switches, so it could be
done without having a "brake" relay on the board.
The idea was to have the board brake when reversing direction since
the computer can switch direction and start sending step pulses
immediately but the actual spindle cannot, so the "brake" would
never engage. I realized that this "brake pause" is probably better
written into software...as in... "pause for .X seconds before
sending step pulses" Most brakes take less than a second to stop
the spindle so a simple programmable delay line in the software
could allow for a brake to stop the spindle (all off) before sending
pulses again. In practice this would mean a .X second delay when
starting any spindle movement, but that's ok. It would hardly be
noticeable.
This is probably a better solution and keeps the board to 2 relays.

Sean

--- In CAD_CAM_EDM_DRO@y..., "audiomaker2000" <audiomaker@s...>
wrote:

> Ok, I'm new and ignorant, and maybe this already exists but...
>
> It would be great if there existed a LPT/VFD control board.
>
> This board would have 3 relays..
>
> The way this board would work is that it would take step signals

and

> convert them to 10 +/- volts output.
>
> A direction signal would engage one of two relays depending on the
> direction
>
> The third relay is for brake and would activate whenever there is

no

> step pulses available, or whenever the direction pulse reversed

(ie,

> fwd/brake/rev)
>
> Does this exist?
>
>
> Sean