Re: [CAD_CAM_EDM_DRO] re:g-code parsers

Les,

Some comments interspersed below:

Les Watts wrote:

>
> > Les,
> >
> > I didn't know what all you were looking for, but I'm sure you get the
> > idea. scanf() and sscanf() are std. 'C'. If you have a token, and you
> > expect a numeric parameter, then "scanning" the token string for the
> > float is a simple way to get the number out (or telling you if you
> > didn't get it).
> Alan,
> Sounds like the much easier way to go!
> All tokens (letters) will be followed by parameters(numbers)
> as I understand. Therefore the first float (or integer) I get out
> will be preceded by whitespace and its token and so on.
> I will play around with it. (or just buy your code??)

There won't necessarily be white space! G01X1.5Y2.5 is legal! get the
tokens, IGNORE the white space, and then get the parms.

> >
> > Did you pick up on the Modal groups? Example, you can only have a G0,
> > G1, G2 *OR* a G3 on a line at one time, they are all in modal group 1.
> > Similarly, group 2 is G17, G18 or G19. And you want to set a flag to
> > say you saw a "move" group command, and at least one axis parm (X,Y,Z
> > etc) to act upon.
>
> I had done a search for all prep functions with coordinate parameters. Even
> G72 and G73.... but I don't know how many
> cam systems use it. I just know I am doing coordinated 3d moves. I must
> study rs274d a bit.

Sounds like you've ALREADY done your homework! G72 don't even come up
on my radar. The language section of that recent NIST URL which was
posted recently is quite helpful.

http://www.linuxcnc.org/handbook/part3/RS274NGC_3.web/RS274NGC_3TOC.html

>
> >
> > The sparse data and curve fitting routine sounds interesting, I wasn't
> > going to go that far, but...
>
> Well a large router has about 10^15 adressable points! But I
> think I can get chordal deviations of less than .001" with most
> moves with control points .01" or more apart with bezier curves.
> I am having to time the routines though because the calculations are
> involved for 3d. I did not write them. I think I can have them ready for the
> old 628 long before it gives me an interrupt. I run it in velocity mode with
> interrupt on breakpoint.
> I can interpolate second order curves of course by commanding different
> accelerations on different axes. But that is just a subset of the more
> general third order b- splines.
>
> At the Atlanta IWF show I saw lots of cnc routers but I was not too
> impressed with the low and mid priced (<$100k) ones.
> They were either slow or gougy. I need something better to get some labor
> content out of my operation here. Heck most of them were just cutting
> squares out of flakeboard or MDF. The best ones I saw were awe-inspiring but
> way out of a small operators price range. I think they were NURBS based.The
> drill is to avoid secondary sanding or finishing by more accurate tool
> paths. Sanding/finishing is the number one labor cost for me by far. About
> 75%.
>
> After a lot of work I have a platform that is stiff and repeatable to .001"
> over a very large work envelope. I just need good software to take advantage
> of that structure.
> >

Yep. I'd say you've done some homework. I have a 5" lathe and a
Sherline mill... for now. ;>)

Alan KM6VV

> >
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
>