RS274NGC G code basics

[Jack Ensor <jensor-at-qis.net>]

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