RE: RS274NGC G code basics

["Pete Cook" <pete.cook-at-alltracorp.com>]

The only codes you can really trust from machine to machine are M00, M02,
M30, G00, G01, G02, G03 &G04. they are the basic standard codes. Most
everything else was dependent on the machine tool builder and the control
maker.(and his desire to try to lock out other brands...) Codes became
somewhat standardized when many contol manufacturers used the FANUC line of
controls, but I have seen machines by the same manufacturer that used
different codes each year of manufacture. And even a few that required G21,
G22, and G23 if you wanted better acuracy.
>
> I have a little experience with G code programing as required by an
> early Bandit CNC add-on to a Bridgeport.  Now looking at the standard
> that is being used in EMC I see I have to learn some new techniques
> and forget about some of the ones I am used to.
>
> However I note a big short coming in the RS274NGC (as detailed in the
> manual) in that there is no allowance for looping and the use of
> subroutines.  Is this really the case or has this information been
> omitted from the manual or did I somehow overlook it?  Actually it
> looks as though there is limited looping and that is for repeats
> within a canned cycle, but I don't see provision for a loop counter
> to repeat through a number of program steps.
>
> A friend loaned me his programming manual for a Haas machining center
> and I see that they use subroutines. M97 for a subroutine call and
> M99 to return from subroutine.  Maybe this is just unique to Haas.
>
> Jack Ensor
>