Messages

41

General Mach Discussion / Progressive Move Error with X and Y

« on: June 29, 2008, 01:38:43 PM »

I'm not sure how to word this and read through some of the posts but didn't see anything that applied.  I finally got to cutting some parts after many tests and realized I have a problem when moving both the x and y axis in G90 or G91 mode.  If I move each axis independently, it always returns to the exact same point.  However, if I move from x0y0 to x1.5y1.5, and back to x0y0 and then finally to x1.5y1.5 I will be off by about 0.042 thousands.  If I repeat this, it is progressive and goes to about 0.084 thousands roughly.

I just don't know where to start with this problem.  The independent x/y movements I believe indicate that my basic motor setup is correct.  So I'm not sure how the xy movement together can cause a progresive move error.  Is the computer itself suspect and possibly not sending the right information or could it be missed steps for some reason when doing both axis?  If it were missed steps, I would have thought it would show up when doing single axis movements too?!

If anyone has any ideas, it would be greatly appreciated.

Best Regards.

Carl

42

General Mach Discussion / Re: Step Pulse Won't Save

« on: May 29, 2008, 05:37:18 PM »

Rich,

OK, I've tried that and a dozen other things but it just won't persist.  The only reason I decided to set it is that I lost some steps when drawing circles at 60ipm.  Was more curious if that would solve the missed steps more than anything.  I'll never need to drive this thing that fast which is a good thing.  When I run it up to 50ipm doing circles it's right on.  I never expected the accuracy I'm getting out of this old thing so I'm pleased.

Thanks again for the feedback.

Best Regards.

Carl

43

General Mach Discussion / Step Pulse Won't Save

« on: May 28, 2008, 08:21:09 PM »

I just finished converting an Enco tabletop mill to CNC and have gotten the x/y axis working fairly good but I have been unable to save the recommended Step Pulse setting.  I'm using Nema 34 steppers (4 wire type from Homeshopcnc) and Gecko 201s and it's my understanding that the Step Pulse should be set to 2.  When I enter this setting and save it appears to work but when I return to the setup screen the value is 1.  Any feedback would be greatly appreciated.

Best Regards.