Re: G80??

[Jon Elson <jmelson-at-artsci.wustl.edu>]

Ray Henry wrote:

> List
>
> I'm attempting to write a brief description for the handbook of the moves
> generated by canned cycles.  Most are fairly well outlined in the various
> RS274* doccuments from NIST.  Dan read the draft and pointed out that I'd
> missed g80.
>
> What I know about g80
> ---------------------
>
> It is included in the motion modal group:
> group 1 = {G0,G1,G2,G3,G80,G81,G82,G83,G84,G85,G86,G87,G88,G89} - motion
>
> In the list of meanings for g words it says:
> G80 cancel motion mode (including any canned cycle)
>
> In the listed order of execution it says:
> 20. perform motion (G0 to G3, G80 to G89).
>
> In the list of error messages it says:
> 29. Cannot use axis commands with G80
> 34. Coordinate setting given with G80
>
> So I take it that g80 works as a software motion lock. I tried it in a nc
> program and it will generate the error messages listed but I can't imagine
> any practical use for it.

The canned cycles are modal.  That means they remain in effect until
cancelled.  So, if you have a drilling canned cycle in force, then every
time you move the X or Y axes, a hole will be drilled at that location
by the canned cycle.  When you are done with the canned cycle, you must
cancel it, before you can safely do any other operation.  You use a
G80 to cancel any canned cycle that may be in force.  It should be set
up so that an extra G80 at the beginning of a program is not an error, but
just makes sure there are no canned cycles active.  But, you have to
follow any other restrictions on the use of the G80 command.
It looks like you would have to reset the motion mode (G00 - G03)
after using the G80.

Jon