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Author Topic: Mach4 Re-Zeroing mid run  (Read 217 times)

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Mach4 Re-Zeroing mid run
« on: August 19, 2020, 05:38:21 PM »
Hey, this is my first post.  I'm trying to find some support out there to help me troubleshoot my issue

The quick one sentence issue: In the middle of one specific program, my machine sets its zero about 1/4" - 1/2" higher than what I set it at.

  • My Machine: Avid PRO CNC 6060 with their plug and play controller, NEMA 34 motors, extended Z travel
  • My gcode: attached
  • What I am machining: An aluminum guitar neck.  Specifically, this file is for the fret slots themselves
  • What is happening: At random parts during this gcode, something is happening to reset my z higher up.  I haven't SEEN the machine do it, it happens when I walk away, which makes it even more annoying.

What I don't think is the issue:
  • The gcode itself.  the problem has happened in the same spot twice, and then in a different spot a third time.  it has also run cleanly
  • The Z pushing too hard down, not penetrating, and leaving with an inaccurate Z.  the bit is a 0.030 mill head, it would snap way before the nema 34 failed
  • overhead.  the room is ACed and should be well cool enough to run

But otherwise, I'm open to hear any possible causes.  It has happen 3 times in a row now, and I am at my wits end trying to find support for any sort of possible solutions.  possible bug? possible contamination in my controller box?  Possible code importing incorrectly from my USB?  Possible something I can't imagine?  Possible it is skipping a line, and it is always a G1 down to depth, leaving it too high all run?
Re: Mach4 Re-Zeroing mid run
« Reply #1 on: August 19, 2020, 06:37:28 PM »
i think its noise problem ,as you know mach not close the loop and if there noise mach cant know the new position ,to be sure if its noise ,you need cheack after that happened ,the actual position and the mach position ,and compare if they are same
Re: Mach4 Re-Zeroing mid run
« Reply #2 on: August 19, 2020, 06:47:57 PM »
noise problem: do you mean like this issue? https://www.machsupport.com/forum/index.php?topic=11760.0

That could be possible.  I can confirm that after it happens, the Mach4 Position and the Actual Position are not consistent.  That is why I thought the issue was zero related, but if the Z axis is enduring RF noise until the smoothstepper can't handle it, that could be possible.  Mach4 wouldn't shut off in that scenario? Or is there a way to make a warning if Mach4 is enduring too much noise?
Re: Mach4 Re-Zeroing mid run
« Reply #3 on: August 19, 2020, 06:54:25 PM »
mach4 not close the loop ,so there almost not any way to know that mach loose the real position,i use servo motors and in that case the servo pack close the first loop ,but also not the second loop ,so also in mine i had that problem
as my experince i can sugest you cheack ground loop
first be sure you have one "0" for all yours power supply ,if you have more then one conect all "-" togethere and ground them
Re: Mach4 Re-Zeroing mid run
« Reply #4 on: August 19, 2020, 07:18:05 PM »
A ground loop shouldn't be an issue, I am using a pre-configured controller box.  The hardware inside I can trust with confidence, they test it on site before shipping.  The problem is also new, I had a month or so of confident running, so I think the RF noise sounds most probable.

I don't know what "close the loop" means?

Offline Bill_O

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Re: Mach4 Re-Zeroing mid run
« Reply #5 on: August 21, 2020, 08:38:14 AM »
If it is a stepper motor system you could be loosing steps.
How fast are you moving the Z axis and what is the acceleration.

Re: Mach4 Re-Zeroing mid run
« Reply #6 on: August 21, 2020, 09:30:56 AM »
Yeah one of the suggestions was that the stepper was losing steps.   My acceleration and top speed are all set by Avid CNC in their profile. 

I contacted them about the issue, and their suggestion was to switch the Z motor smoothstepper pins to be Active Low instead of Active High, but they didn't know why that has been helping with some of the issues they have seen.

They did also say that the pins already have the highest noise filtering on, but the line in the ESS is just "-----"
Re: Mach4 Re-Zeroing mid run
« Reply #7 on: August 21, 2020, 09:35:26 AM »
i repeat on my sugets ,cheack that all yours  dc supplier minus is ground ,in europe machines its always like that ,its save many troubles