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Author Topic: Problems with upgrade to 4.2.0.2914  (Read 2223 times)

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Offline Pedio

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Problems with upgrade to 4.2.0.2914
« on: August 07, 2016, 02:27:06 PM »
I recently upgraded Mach 4 to 4.2.0.2914 with the new PMDX plugin software 0.44.214.

Background - I use a laser to do artwork and will often have very large gcode files that have lots of small moves. Many times an object is filled in using .005" laser lines and lots of odd shaped figures. What this means is my machine does lots of moves and any problem tends to accumulate over time. My machine is set up in inches.

What I saw after I upgraded Mach 4 and PMDX was that after filling in a large area the machine would be off of the original location. See the cutting board picture attached. The Gcode did the first few letters and then went to the scroll work. When it came back to the letters it was off.

To help troubleshoot this I made up a test pattern that drew a square and put a number into the square. It then filled in another square by using a back and forth motion. The fill is actually one long line that goes across at a 45 degree angle. Everything seemed to work fine (slight square overlaps are probably in the Gcode file). See attached

I then made a pattern of a number of random dots and filled them in using a 45 degree line. This caused the problem. (see attached). I drew the number 1 square before I started and then again after the first pass of filling in the random dots. You can see that it was off. I then filled in the random dots again and drew the number two square. This was done with the acceleration at 20 and the rapid at 200 in M4. The feed rate was 30.

Although I have never had problems I thought that this might be due to over driving the stepper motors so I slowed the machine down to acceleration of 10, rapid at 100, and feed rate of 20. The problem was still there. (see attached)

I have run my machine much faster than this in the past. I have a router on the machine. Since I was using the laser it did not have to push through anything that might have stalled the stepper motor. The problem seems to show up when the machine has to make a lot of rapid moves. Any thoughts?

Offline Pedio

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Re: Problems with upgrade to 4.2.0.2914
« Reply #1 on: August 07, 2016, 03:27:44 PM »
I slowed the acceleration down to 7 and the square was off almost exactly the same amount as the acceleration at 10.
Re: Problems with upgrade to 4.2.0.2914
« Reply #2 on: August 07, 2016, 04:47:09 PM »
Try cutting the rapids way down. At least it it stops the problem you will know if it is the machine or not.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: Problems with upgrade to 4.2.0.2914
« Reply #3 on: August 07, 2016, 10:54:42 PM »
On the first image (the cutting board).  The last two letters look off (shifted down) - that I can see.  Does any of the image above the letters look "off"?  Or does the image look fine and only the letters are offset?

In the 3rd image (the first one with the filled-in dots) - of the two "1" box images, do you know which one was drawn first?  I.e. was the 2nd one shifted up and to the right?  Or down and to the left?  I'm guessing "down and to the left".

Can you send me another profile package (just to make sure I've got your most recent) and the GCode file that you used to create the 3rd and 4th images?  I only need the part that draws the #1 box, then some random dots, then re-draws the #1 box.  You can post them here if you like or email them to me.

Bob

Offline Pedio

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Re: Problems with upgrade to 4.2.0.2914
« Reply #4 on: August 08, 2016, 09:30:44 AM »
Bob,

Will send you the files later today. I have run a number of other files as well. The small dots that fill in appear to move slightly as the file progresses, e.g., the dots toward the ends of the file seem to be more in line with the outline (outline is drawn last on most of the artwork I do). I plan to draw a box around the outside of the random dots so I can see if the files move off as they process. Most of the dots are drawn and outlined from the top right to the bottom left. If I draw a box around the dots first I can see lines of dots shift as the file progresses. I will run the file before I send it to you to make sure it show the problem.

The cutting board Gcode file drew the first few letters, then drew the different parts of the black wreath, and then drew the other letters. Each part of the wreath is drawn and outlined separately. I suspect each part of the wreath was a little off from the previous part.

I have checked the machine to see if there was any play in it. Also, I cleaned the mechanical mechanisms just in case. I would suspect if something were loose or jamming it would not have a error on both axis - but you never know!

As I mentioned before these are really big Gcode files. They are much bigger than a 4'X8' sign with wood grain that I would make on the same machine. This would mean a small error would show up more often.

Also, I ran a file with the following - Rapid 50, acceleration 7, and feedrate at 20 and I had approximately the same offset as the second random dot pattern.

P

Offline Pedio

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Re: Problems with upgrade to 4.2.0.2914
« Reply #5 on: August 08, 2016, 09:34:26 AM »
Bob,

Also, I think the box was moved up and to the right. I think I will use Xs drawn on some indexing lines to make sure of the direction and spacing. I will draw the indexing lines first.
Re: Problems with upgrade to 4.2.0.2914
« Reply #6 on: August 15, 2016, 05:44:18 PM »
To close this out for now, at least, the issue has been resolved by changing the step pulse polarity to active low, which for his drivers (Geckodrive G201X with COM=5V) was the proper setting.

Offline Pedio

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Re: Problems with upgrade to 4.2.0.2914
« Reply #7 on: August 16, 2016, 08:42:52 AM »
The guys at PMDX were great in helping solve the problem.

Great after sale service!