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Messages - rrc1962

361
General Mach Discussion / Re: G31 Probe problem
« on: July 31, 2011, 12:52:37 PM »
NOW back to the original thread (;-)

Please lets us know the results of the G31 testing as used in the TOM routine used for plasma and run from the M3 macro.

(;-) TP

I don't run the probing code inside the M3 macro.  That code sits in it's own macro.  When that code is finished, the M3 fires, which is in Gcode.

362
General Mach Discussion / Re: Breakout Board
« on: July 31, 2011, 12:47:13 PM »
Sorry...I copied it but forgot to post it....122 is on the same site...

http://www.pmdx.com/PMDX-126

363
General Mach Discussion / Re: Breakout Board
« on: July 31, 2011, 12:27:57 PM »
Here's another one that fits your specs pretty well.  We use the 122 and love it.  If you're talking about putting optos on the step/dir outputs, that's not necessary.  Any drive worth buying will already have optos on the step/dir inputs.

364
General Mach Discussion / Re: G31 Probe problem
« on: July 31, 2011, 11:34:08 AM »
I'm not sure what happens under the hood on Mach3, but I know that if you omit the While IsMoving() statements, the code sort of runs away and goes out of time.  If I understand correctly, you are saying that the wait statements slow it down.  How is that?  All they are doing is simulating what would happen in GCode anyway.  Just making sure that the commands in order and one does not execute before the other.

I know for sure because I've tested it, that this code in a macro....

code "F30"
code "G31 Z-1"
While ismoving
Wend
code "G92 Z-" & offset
While ismoving
Wend
code "G00 Z" & pierceHeight
While ismoving
Wend


and this code in GCode...

F30
G31 Z-1
G92 Z-0.1500
G00 Z0.1250

Yield the same results...Or close enough to the same to not be detectable by eye.  One does not execute any faster than the other, and in 8 years or so, the macro version has been 100% reliable.  Keep in mind that we're talking about torch referencing, not point cloud probing.  A slight timing difference would be perceivable if you were running a program probing a few hundred times vs just a few times per job to reference a torch.

I'm not doubting your results, just curious as if there is a way to speed up probing, I'd like to try it.

RE: The M3 issue.  I had never seen that until the last machine we put together.  The problem was random but frequent.  I replaced the PC with another of identical make and specs and the problem went away.  M30 would also not execute.  No problem with any other M codes though.

365
General Mach Discussion / Re: G31 Probe problem
« on: July 30, 2011, 10:47:11 PM »
rrc1962 and DaveCVI, could you post your probe script?



code "F30"
code "G31 Z-1"
While ismoving
Wend
code "G92 Z-" & offset
While ismoving
Wend
code "G00 Z" & pierceHeight
While ismoving
Wend

One thing I've noticed is that G31 does not use the acceleration setting for the Z axis.  It uses either the X or Y acceleration settings, even if you are probing the Z.  If you have a very low acceleration setting on the X and Y and something higher on the Z, don't be surprised to see actual acceleration on Z probe not match your Z acceleration settings.

366
General Mach Discussion / Re: Exit Button
« on: July 30, 2011, 07:29:39 PM »
Perfect...Thanks very much.

367
General Mach Discussion / Re: G31 Probe problem
« on: July 30, 2011, 04:55:34 PM »

To date, I have direct experience with a pretty good size user base that does probing operations, with mach, via scripts, day in and day out, and they have been doing this for between 1 and 2 years now.


I agree...I've been probing inside macros for years.  I don't find that it stops any faster if the same code is placed in GCode.  I probe at 30IPM and typically see about 1/8" of over travel.  Also running fairly high acceleration on the Z, so maybe that's why.

368
General Mach Discussion / Exit Button
« on: July 30, 2011, 04:47:02 PM »
Is there an OEM code to exit Mach3.  Trying to create a mouse free environment...or as mouse free as possible....for a touch screen.

Thanks

369
General Mach Discussion / Re: G31 Probe problem
« on: July 29, 2011, 09:59:08 PM »

 The G31 will ALWAYS use the Deaccell curve to stop


My point was that unless Mach knows where it is stopping, it can not decel to that point, thus when the probe is triggered, Mach stops, but because it has to decelerate, it never stops on the mark.  Slowing the feed rate gets it closer to the mark.  The OP wanted to stop on a dime at 60IPM, and that's not going to happen, regardless of where the code is.

The behavior is similar to the THC commands in that the slower you make the THC feed rate the less overshoot...or bounce, you get.

370
General Mach Discussion / Re: G31 Probe problem
« on: July 29, 2011, 12:50:30 PM »
Accel and decell are only really a factor on commanded moves because the Mach knows where it is stopping and plan the deceleration to that point.  When you probe, Mach has no idea when the probe will trigger.  When it triggers, Mach says stop, but it never stops exactly on the mark.  That's the same reason the THC commands overshoot.  The faster the THC feed rate the more overshoot you have.  The solution to both is to turn down the feedrate.  I probe at 30IPM with is a acceptable compromise between overshoot and speed.  The slower you make the feedrate, the closer you'll come to stopping on the mark.