Re: [CAD_CAM_EDM_DRO] Single-wire step and direction

On 2 Jun 2005, at 06:12, Mariss Freimanis wrote:

> The concept is simple. A step pulse narrower than 2 uS is decoded as
> a CW step. A step pulse wider than 2 uS is decoded as a CCW step.

I wonder if the PC based controller systems currently in use have
hard enough realtime characteristics to guarantee that a pulse will
never get postponed long enough to turn reverse the direction of a
step if this method is used.

How about this instead: use a flip flop (or a memory bit in a uC) to
store the current direction. Short pulses step in the current
direction. A relatively long (say 500 uS) pulse followed by a
relatively long (500 uS) off-time sets the flip flop to one direction
and a long pulse which is on for the whole time (in this case 1 ms
on) sets the flip flop to the other direction. This would only cause
a thousandth of a second delay when changing direction and wouldn't
require such tight timing requirements of the controlling PC.

--
------------ Alex Holden - http://www.alexholden.net/ ------------
If it doesn't work, you're not hitting it with a big enough hammer