Re: rs274

Hello,

While the nist 274NGC doc has some good info, you should not confuse
it with 274D. They are NOT the same thing.

274NGC, as defined by NIST in the EMC interpreter, is a derivative OF
274D, and is based largely on a Document the NIST biblio footnotes
refer to as NCMS. This NCMS doc is nothing more than an allen bradley
cnc control user manual, supplied to NIST for use in coding the
interpreter.

And the listing in the machinerys manual is ALSO NOT 274D... IMO, it
is so far out of date(unchanged in recent editions) with the "de
facto" g code std. as to be misleading and irresponsible.

I posted more extensively on this subject last night in the TurboCNC
forum. (Might have been SherlineCNC)

Hope this helps,

Ballendo

P.S. The real ansi/eia rs 274D standard is dated november 1980. A LOT
has changed since then! Over the last 23 years what I call the "de
facto" std. has emerged. De facto is simply the market driven result
of two decades of trying to fit new ideas into the old 274D. Fanuc is
clearly a leader in this respect, and much of what THEY use, nearly
everyone else uses too. MANY things which had diverged over the years
have come back together, and now we can nearly always expect inch/mm
units selection to be called by G20/21. These codes are the "de facto
std. for units selection. 274D says to use G70 and G71...

Additionally, many gcodes which once were needed due to low memory
and speed of computers in 1978-1980 (when the std was written), are
no longer necessary, or used. In their place NEW godes (usages of
codes,really) have emerged.

If you are WRITING a cnc control, it's a good idea to look at 274D.
But if you are trying to learn CNC, you're better off with an owners
manual for the control (ot control type) you wish to learn...






--- In CAD_CAM_EDM_DRO@yahoogroups.com, "bull2003winkle"
<bull2003winkle@y...> wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "asi" <asigraph@b...> wrote:
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...>

wrote:

> > hi jon thenks but icant find it ineia website
> > if u can help me ther is a link?
> > thenks asi
> asi:
> Here is a link to a web site that has a lot of data from RS274 that
> originally came from NIST.
> http://www.linuxcnc.org/handbook/RS274NGC_3/RS274NGC_33a.html
> There is also a coopy of it starting on page 1246 of Machinery's
> Handbook Vol 26
>
> Hope this helps;
>
> Ken