Re: [CAD_CAM_EDM_DRO] A crazy idea

Mariss

I would be concerned about two things:

1) the definition of "narrow". This could result in platform speed
dependancies.

2) Changing an axis from CW to CCW motion (or CCW to CW motion). I have
to do this all the time in my Stewart Platform, and I would think any
machine tool cutting contours would have this problem as well. It would
not be good to require a "long" delay when switching directions.

-- Carl

At 02:21 PM 6/6/02 +0000, you wrote:

>Hi,
>
>Parallel port output CNC programs are limited to 3 or 4 axies because
>of the limited number of port bits. Each axis requires a STEP and
>DIRECTION bit pair. What if it could be done with a single bit per
>axis where STEP and DIRECTION were combined on the same line? It then
>would be possible to run 6 to 8 axies.
>
>Here's how it could be done:
>
>(1) 100000000010000000001000... is CW
>(2) 011111111101111111110111... is CCW
>
>In (1), a narrow positive going pulse would be interpreted as a CW
>motion. In (2), a narrow negative going pulse would result in CCW
>motion at the same speed. One would simply invert (1) to generate (2).
>
>This scheme would place no additional burden on the software or on
>the bandwidth of the now combined STEP/DIRECTION compared to a
>standard STEP pulse line. Decoding hardware in the drive would be
>minimal; just a single quad gate package.
>
>So, what do you think, a crazy idea?
>
>Mariss
>
>
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Carl Mikkelsen
Oasis Semiconductor, Inc.
201 Jones Road
Waltham, MA 02451
(781) 647 8775