G54 problem-Work offsets

[romer]

When using multiple work coodinates with the same tool, if G54 is the first w.c., using G55, G56, etc.,in any order, will output the proper sucessive w.c. code. However if anything other than G54 is used as the first w.c., when G54 is called, it is output as whatever was the first w.c.

I am using MPfan post processor.I have also tried MPEZ and MPmaster from this site. They all do the same thing.

I assume it must be in the post processor.

Has anyone run into this?

 

[Guest CNC Apps Guy 1]

Set your work coordinate in the T/C Planes page as well.

James Meyette

[romer]

James,

I assume you are refering to the tool plane/construction plane dialog box that is accessed from the tool parameters window. That is what I'm doing. Is there some other way to change work offsets in V8?

[Mark H]

Just a quick thought, in the TC plane dialog box try using 0 (zero) instead of -1 for the tool plane, they both set the wcs to G54.

-1 = default

0 = G54

Let me know if it works.

[romer]

That did the trick. Thank you.

However, now I am curious as to how I can change the default from "-1" to "0". Would there be any reason not to?

Changing in the defaults.df8 using operations manager did not make a difference.

I also had a chance to try V7 mpfan from dealer that worked fine but no sub-progam support. Comparing the "pwcs" parts of the post processor, they are written differently but I can't figure the specific logic statement that would cause one to work fine with "-1" and the other not to.

Any additional help would be appreciated.

[Guest CNC Apps Guy 1]

Version 7 did not support Sub Programs except for CUSTOM posts.

V8 Does it out of the box.

[Mark H]

I have run across the same problem with the work offset in the Defaults.df8 file. Even though you save the work offset in the Defaults.df8, it is not read in to your toolpath. Maybe Mastercam can fix that in its next release.

I’m sure there’s a reason why someone would use the work offset = -1 over the work offset = 0, but I haven’t found a use for it. I figure someone went through some trouble to put it in, so it must have some purpose.

As for the V7 versus the V8 mpfan.pst pwcs logic, and its just a guess, but it’s possible that the reason it works in one and not the other is that it is the MP.DLL that handles the work offset “workofs” differently and its not the pwcs logic.

[This message has been edited by Mark H (edited 01-23-2001).]

[Luther Heggs]

A work offset of -1 means OFF. 0 (zero) is a valid work offset number on some controls.

[Allan Brown]

-1 tends to mean 'auto' or 'unchanged from previous' as opposed to 'off'.

Another related thread: http://www.emastercam.com/ubb/Forum1/HTML/000527.html

[Mark H]

OIC

So if toolpath #1's work offset = 2

and toolpath #2's work offset = -1

then toolpath #2 will use toolpath #1's work offset.

(Assuming they are posted in the same NC file.)

Good, now I dont have to remember to set the work offset for each subsequent toolpath that has the same work offset. You can never stop learning.

Now where the confusion came about was that mpfan.pst outputted a G54 for the first toolpath even though the work offset was = -1, you would think that it wouldn't output any wcs.

So for the mpfan.pst, when the work offset is -1 then the last wcs will be used, unless its the first toolpath, then the wcs will be G54. Got it!

[This message has been edited by Mark H (edited 01-23-2001).]

[Mark H]

After looking at mi1...

I guess it should output a G54 for the first tool because the mi1 = 2. In the mpfan.pst mi1 reads "Work Coordinates (0-1=G92, 2=G54's)"

[d0gFartz]

yeh.....set mi1=2 to use g54`s

0 thru 5 for 54 to 59 6 on up for the 54.1

positions...ie G54.1 P1 is offset 6

[Allan Brown]

In the Mpmaster post on this site I did away with mi1, because people tend to use a single WCS method. We like to essentially lock it in the post.

Instead I use a 'wcstype' switch in the post that acts in the same manner as mi1, with the exception of being able to shut the WCS off altogether with a value of 3. This is documented in the post itself.

[This message has been edited by Dave Thomson (edited 01-24-2001).]