Re: [CAD_CAM_EDM_DRO] Re: tool changer logic- mathematical challenge

Jeff Jones wrote:

>Am I missing something? Seems pretty simple to me. I think.
>
>Assuming the opeing in the "C" is about 90 degrees (maybe a skosh more
>to allow for the lamp width) every 45 degrees would have a unique value
>at the sensors. At any one time either one or two sensors would be
>illuminated and the other 2 or 3 will not be. It's a fairly simple
>table-driven matter to map that pattern to tool numbers 0-7. A PIC would
>do the trick quite nicely.
>
>Jeff
>

I think you're missing something :)

If the opening is 90+ degrees, then there's a 90- degree span over which
the sensor output doesn't change, so you won't see a 45 degree change in
toolholder position.

Consider it this way:
First, assume that sensors are at north, south, east, west, and that
"home" has the C with its opening centered around east (like a C, with
45+ deg exposed both above and below the X axis).
I'll write sensor output as ENWS (east, north...), so the initial
position is 1000.
Now, rotate the C 45 degrees counterclockwise: E is still uncovered, and
the other 3 are covered (still 1000). When the N sensor turns on,
you're at the next tool position (1100). (so far so good)
Rotate another 5 degrees or so (just a hair over a scoche :), and you're
at the next state - 0100. First oops.
Basically, this setup will work for every second tool, but won't move
far enough for the other half of the positions.

Hopefully that was clearer than mud.

- Steve