Re: [CAD_CAM_EDM_DRO] another EMC Glitch?

Les,

If you want to do more than one piece without losing the offsets
leave off the M30 at the end of the program. EMC will complain
with a message box each time you run the program, but you can
just hit ok and press on. Everything works fine and as it should.
It's the M02 or M30 that causes it to forget where it is.

Bill

> Speaking of glitches.....
>
> I think the G92 offset thing is still with us. I have a modified version
> of BDI 2.14 (I think) that Paul installed so mine is pretty new.
>
> I had to do a dive for the e-stop yesterday.
>
> I haven't figured out exactly what's going on but M30 program stop
> removes an offset from the GUI- but it seems to be still there in
> the controller at least sometimes.
>
> I set G92 Z0 after jogging the tool to the work surface usually.
> My Z0 is normally at the center of travel. If I do the next plank
> and reset Z offset I am apt to have about double the amount I want
> with no indication in the display.
>
> With 2500 lb force capability in my machine I could some real damage.
>
> If anyone knows where this offset stuff is in the source code I could have

a

> look.
> This is a bad thing. Must be a canonical function or something.
>
> On a similar note I have the spindle force detector about ready to
> breadboard.
> I am just doing it analog for now. It's pretty simple- acceleration force
> and
> spindle force are separated by analyzing servo current and tach signals in
> real time. Just doing some summing, multiplying, differentiation,and

square

> roots
> with op amps to see if it works. The only rub is that transmission

friction

> forces
> have to be considered as well, and they are not constant. But with a

simple

> linear
> approximation for friction , but I think I can have estop go off with

about

> a
> 200 lb spindle force, while maintaining the 2500 lb force capability for
> rapidly accelerating the gantry. That would help a bit with things like
> this G92 weirdness or an operator error.
>
> If it works this could be performed with no accelerometers or force

sensors

> on the spindle (at least with servos).
>
> Kind of an electronic shear pin...
>
>
>
> Les
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.alltel.net/~leswatts/wattsfurniturewp.html
> engineering page:
> http://www.alltel.net/~leswatts/shop.html
>
>
>
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