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Offline Tweakie.CNC

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G31 command.
« on: May 14, 2012, 03:48:10 AM »
Hi Guys,

I would be most interested to hear of others experiences using the G31 command.

I have been using it for some years now and with the exception of having to liberally add the ‘While isMoving() / Wend’ statements to the scripts (following a Mach revision some time ago) it has worked perfectly and without any other issues.

Does it sometimes go cranky and what is the suspected reason??

Your comments would be much appreciated.

Tweakie.
KEEP SAFE !

Offline stirling

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Re: G31 command.
« Reply #1 on: May 14, 2012, 10:40:22 AM »
Hi Tweakie - Can I throw in a suggestion? Restrict your question to G31 issued from gcode and the MDI ONLY. Otherwise I think your waters will be muddied (not a pleasent thought  ;D) by things that went wrong with G31 in a macro that likely had nothing to do with G31 itself.

example: do a macro based code G31 followed by a code G1 with and without a while isMoving() construct between them. What happens next is entirely version dependant and in those cases where the G31 fails it generally has nothing to do with the G31 command itself.

Ian

EDIT: Maybe I've misunderstood and you're interested in G31 in scripts in particular - sorry!
« Last Edit: May 14, 2012, 11:38:48 AM by stirling »
Re: G31 command.
« Reply #2 on: May 14, 2012, 10:55:33 AM »
FWIW - I did have problems with G31 with the SmoothStepper.  I think most/all of these problems were eventually resolved, but there were times when it would do just plain bizarre things - like moving opposite the commanded direction, moving the wrong axis, moving the wrong speed, even moving multiple axes.  This cost me more than a few probes (I was using rigid probes).  But, then, I seemed to be plagued with all kinds of problems that nobody else had.  Happily, since switching to a KFLop, and my own custom CNC controller app, I haven't had one single problem of any kind, and the whole system has become dead reliable.

Regards,
Ray L.
Regards,
Ray L.

Offline BR549

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Re: G31 command.
« Reply #3 on: May 14, 2012, 06:42:23 PM »
HIYA tweakie,  The G31 ran from Gcode is fairly dependable. I have Gcode ONLY routines that run for many thousands of cycles probing engine cylinder head ports.

The problem is when you MIX CB macro  AND Gcode in the same macro. Most times you have to cripple the macro by adding a LOT of long wait states in attempt to kept the running order in sync. Then it becomes clunky and SLOW to execute. Almost useless at that point.

I do see a problem in the G31 Gcode itself.  It gets confused on the accel / Deaccel  it uses sometimes(;-) and MAY cause an overun sometimes where it COULD break a tip. We found it testing the G31 for the TOM routine in plasma.

Ian probably remembers that one now that I mentioned it.

(;-) TP

(;-) TP

Offline rcaffin

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Re: G31 command.
« Reply #4 on: June 20, 2012, 02:36:16 AM »
Quote
I would be most interested to hear of others experiences using the G31 command.
Most unhappy with executing g31 from MDI under Mach3 R3.043.022

I opened a log file with g40, then executed a series of g31 commands across a work piece, then closed the file with g41 - all via the MDI.
The first line in the log file  was correct. The next 6 lines, for locations separated by 200 mm or more, were all the same, and all completely wrong anyhow.
has this been reported before?

Cheers

Offline rcaffin

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Re: G31 command.
« Reply #5 on: June 20, 2012, 02:54:07 AM »
Quote from: rcaffin
Quote
I would be most interested to hear of others experiences using the G31 command.
Most unhappy with executing g31 from MDI under Mach3 R3.043.022
I opened a log file with g40, then executed a series of g31 commands across a work piece, then closed the file with g41 - all via the MDI.
Which obviosuly should have been m40 and m41!

Cheers