Author Topic: Mach3 losing steps  (Read 13848 times)

0 Members and 1 Guest are viewing this topic.

Offline fam891

  • Active Member
  • Posts: 13
    • View Profile
Mach3 losing steps
« on: October 05, 2010, 01:41:05 PM »
Hi all.  We recently upgraded one of our plasma cutters to Mach3 from Mach2.  After doing so, we noticed that the x and y axes would lose steps.  In other words, if I was to zero the torch, drive around the table for a few minutes, and return to zero, the torch would be 3/16" away from zero in both directions (both negative x and negative y).  After trying to change every setting imaginable within Mach3, and swapping drives around, etc, I reinstalled Mach2.  Now the torch goes back to zero as it should.  Does anyone have any idea what would cause Mach3 to "lose" steps on the same setup that works perfectly with Mach2?

Thanks,
Frank

Offline Hood

  • Mach4 Alpha
  • Posts: 25,775
  • Carnoustie, Scotland
    • View Profile
Re: Mach3 losing steps
« Reply #1 on: October 05, 2010, 03:21:15 PM »
Have you got the same motor tuning, been a while since I used Mach2 but seem to remember things are a bit different regards motor tuning. Other thing to make sure is that you have the active state set correct for the motor outputs and maybe also try  a wider pulse width and Dir prechange (Motor Tuning page)


Hood

Offline fam891

  • Active Member
  • Posts: 13
    • View Profile
Re: Mach3 losing steps
« Reply #2 on: October 05, 2010, 03:28:43 PM »
Hi Hood.  Thanks for the reply.  The motor tuning for steps/unit, velocity, and acceleration is the same, except that the velocity is in units/s (Mach2) instead of units/min (Mach3).  In Mach2, I left the default settings the same for pulse width and prechange.  All works good with Mach2.  In Mach3, I tried to change the pulse widths from 1 to 5us.  The lower the number of microseconds, the worse the motors ran.  I didn't see a dir prechange setting in Mach3.  I also tried to flip the active setting on each motor and it didn't make a difference.  Any other ideas?

Offline Hood

  • Mach4 Alpha
  • Posts: 25,775
  • Carnoustie, Scotland
    • View Profile
Re: Mach3 losing steps
« Reply #3 on: October 05, 2010, 03:39:15 PM »
It is the Dir Pulse it calls it in Mach3.
Try a higher setting for the pulse width, possibly up to 15.
If that doesnt help then attach your xml's for both Mach2 and 3 and I will see if I can find a problem.
Hood

Offline fam891

  • Active Member
  • Posts: 13
    • View Profile
Re: Mach3 losing steps
« Reply #4 on: October 05, 2010, 06:54:57 PM »
I tried to change the Dir pulse width to 15, and then to zero.  There was no effect on the error.  I have posted the xml files for both Mach2 and Mach3.  One thing to note is that every once in a while, the start of a movement will cause the steppers to "grunt" a bit, and it sounds similar to a stalled stepper.  However, this only happens when using Mach3, and it happens randomly.  I have checked all of the mechanics of the machine, and the linear bearings and drive components all operate smoothly; not to mention that it only happens when using Mach3.

Frank

Offline Hood

  • Mach4 Alpha
  • Posts: 25,775
  • Carnoustie, Scotland
    • View Profile
Re: Mach3 losing steps
« Reply #5 on: October 05, 2010, 07:07:49 PM »
What are the specs of the computer?
Hood

Offline Hood

  • Mach4 Alpha
  • Posts: 25,775
  • Carnoustie, Scotland
    • View Profile
Re: Mach3 losing steps
« Reply #6 on: October 05, 2010, 07:15:15 PM »
Just looking through the xmls and first thing I notice is  you are using 25KHz kernel on Mach2 but you have 45KHz for Mach3. Try setting it down to 25KHz and see if that helps.
Hood

Offline fam891

  • Active Member
  • Posts: 13
    • View Profile
Re: Mach3 losing steps
« Reply #7 on: October 05, 2010, 09:01:05 PM »
I changed Mach3 to 45kHz when it was not working to see if that would help.  It was originally at 25kHz.  Changing to 45 didn't make any difference.  The computer is a dell, about 3 years old.  I don't have specifics with me as I'm not at the office anymore.  I can post them tomorrow.

Frank

Offline Hood

  • Mach4 Alpha
  • Posts: 25,775
  • Carnoustie, Scotland
    • View Profile
Re: Mach3 losing steps
« Reply #8 on: October 06, 2010, 02:11:49 AM »
run the driver test and see what it looks like.
Hood

Offline fam891

  • Active Member
  • Posts: 13
    • View Profile
Re: Mach3 losing steps
« Reply #9 on: October 06, 2010, 10:32:00 AM »
Hi.  Here are the results from the driver test.  I ran it all the way up to 100kHz and it worked great.  I have also attached the specs for the computer.