G92 and G52 - How SHOULD They Work?

[RICH]

From one who is not the sharpest tack on coding.........

G52 can be used to shift the original offset ( G54) by some value and can be cancelled thus the original work offsets are not changed as compared to using a G10 which would permantely change the offsets. I have an example of how to use the G52 in the LazyTurn Manual ( located in Members Doc's ) Appendix "F" page 14 of 21 section 6.2.
Note that you need to have an offset in place before using the G52.

If wrong feel free to correct...
FWIW,
RICH

[fixitforgood]

Hi guys, new to your forum site! To my knowledge, G92 does give you a new permanent work offset, as you specify in your program. I first saw it in a bolt hole circle program, where the threads were cut with a threadmill, and the programmer wanted to change the absolute offset for every hole on the part, so he wouldn't have to use G91 to incrementally cut the threads. (which is the way I am used to). He uses G92 extensively in surface grinding too. I've noticed that on our Haas control, (if I remember correctly) inputting something into G52 will go back to zero when you press reset, or it comes to optional or programmed stop. Our Kuraki horizontal machining center, it will stay there till you change it. G92 is inputted in the program, G52; while doing the same thing for you, is inputted in the offsets page. An example of needing to use both would be if you shift your X0Y0 offset with G92 in the program, and you are cutting a face into something, and your tool didn't go in deep enough... so you go to your offsets page, move in your G52 Z to the amount you think itll clean up, and re-run the tool.. and take the G52 Z back out, because you don't want the other details to cut that deep (or a tool to crash if your R-plane is close enough).

-Eric

[fixitforgood]

One more thing about G52... If your control doesn't zero out what you've inputted in G52, whatever you input into G52 will change (or add) every offset in your program by that amount. ex: if you put -5. in the x, it will add -5 into any offset running in the program... not just one. The first thing I do before I run a part from somebody else running the machine is to check the G52. You never know when somebody put something in there, and forgot to tell you!!

[BR549]

With Mach3 it is NOT a good idea to use BOTH at the same time.  Many controllers use the G92/52 differently best NOT to confuse Mach3 with ANY other controller but go with what is defined in the manual.

Generaly speaking the G92 is a local offset and the G52 is a global offset.

Just a thought, (;-) TP

[RICH]

Terry,
I am confused some.....
Does G92 provide an offset from the part back to the the tool / controlled point, where as, G54 provides provides for an offset from the controlled point to the part.
Too much Smid on the brain  or  my notes.

RICH

[BR549]

We may all be confused.  G92 shouldl offset the part in the current fixture(SayG54). AND I believe the G52 SHOULD offset ALL the fixtures as well.

But I remember the MACH3 manual WARNS that is is NOT a good idea to do both at the same time.

Mach3 does NOT always follow the Fanuc conventions (;-)

Might be time to TEST both to be sure.

(;-) TP

(;-) TP

[BR549]

BY the manual I have it backwards G52 is local and G92 is global, G92 actually reset internal parameters when in use. It warns NOT to use the legacy G92 when other offsets are applied. And it advices not to use both G52 and G92 at the same time.

I can tell you for sure with G92 in effect strange things happen form time to time whether it is MACH3 or self inflicted they do happen(;-)

Sticking with G52 and G10 was very stable

I 'd have to look up the Fanuc version again to be sure.

Just a thought, (;-) TP

[ger21]

If you do a G52, the offset will also show up in the G92 DRO, so they do seem to share internal parameters.

[RICH]

Will admit not the sharpest tack on all the different codes. A few notes from my notes on use:
- G92 is an old /  legacy command and was basicaly replaced by G52 along with the G54 / work offsets
- G52 - a temporary offset - you need to have a work offset in place since it offsets the original offset by some value and can be cancelled thus
  the original offsets are not cancelled
- G10 will change the workoffset

The only time I use the G52 is for code form  Lazyturn.  Attached is how to use it from the LazyTurn Manual Appendix "F". Thanks to Grayham for
showing me how to use it.

RICH

[rcaffin]

Works OK if I run it on my laptop, but when I run it on the PC on my mill, as soon as I enable the KFlop, all four axes start jogging, and never stop.

Laptop is floating, PC isn't?
60/120 Hz noise, wrong signal polarity, ... ?

Cheers
Roger