Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kthomson on October 20, 2009, 08:12:11 PM

Title: G0 Problem
Post by: kthomson on October 20, 2009, 08:12:11 PM

I have been having a problem with Mach3 for a while now that I can't figure out. About a year ago I changed from WinCNC to Mach3, changed my drives, etc., and for the most part everything works fine. The only problem I've had is, when I manually type in a 'G0 X## or Y##' command, just about every time (99%+) the axis will move anywhere from 2" to 24" (+/-) and both axis will lock up and the motors will 'scream' until I hit <ESC>. I can jog the machine in high speed with no problems, and it has only happened once or twice in a program (obviously with catastrophic results to the part), but it happens almost EVERY time I use a G0 manually. At that point I have to go back and re-home my axis to make sure the machine knows where it is.

I have experimented with the ramp speed, which is currently set to max time to full speed, and the top speed (currently set far slower than I was running in WinCNC), but nothing has helped to this point. I looked under the FAQs and didn't find anything addressing this. Does anyone have any idea what this problem may be.

I only changed the interface and software, the drivers and motors are the same ones I ran under WinCNC.

Title: Re: G0 Problem
Post by: RICH on October 21, 2009, 12:28:59 AM

I suggest the following.
Whatever your max velocity is ( were the motors will start to skip ) set your velocity to 70% of that max setting.
Adjust the acceleration also. That should keep you from skipping steps.
RICH

Title: Re: G0 Problem
Post by: Hood on October 21, 2009, 02:58:44 AM

Your drives may require a wider pulse, try setting the pulse width and Dir prechange to 5 or even trying sherline mode.
Hood

Title: Re: G0 Problem
Post by: kthomson on October 21, 2009, 02:29:11 PM

Rich: I don't know what the max speed is, but I already have it set FAR below the max speed I was running in WinCNC, where I never had this problem. I have also already set the acceleration ramp to MAX (longest time from 0 to max speed) but it has not helped.

Hood: I'll give that a try this weekend. I won't be home again until Saturday, but this is something I have not tried.

Again, it only seems to be a problem when using the G0 command in manual mode, in a program it works fine, which is what I find confusing.

Thanks