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Please help
« on: November 03, 2008, 11:17:58 PM »
Hi all I have been using mach2 mill on my home converted mill for about 4 years with no problems, until my machine PC's hard drive took an instant and massive dump, and I lost the version # I was using.
So I brake out the lap top to finish some CNC work and it has a newer version on it. V7.26. No big deal, I was able to configure the ports and pins OK.
Now the mill is running again but the Mach program is not stopping where the G code is commanding it to.
I can see it in the Z axis, The commanded cutting depth is -.014 and clearance height is .100 For an engraving job that I do all the time.
The mach software sometimes stops at -.013 or -.016 or -.015 and sometimes -.014, When moving to clearance height it stops at .098 or .099 or .101 and sometimes .100, What is up with that? ???
It is like the software is thinking, oh this is close enough. I have never experienced this problem before.
I am using a Rutex closed loop servo system. 5 turn per inch ball screws / 12 tooth drive gear / 24 tooth driven gear with a timing belt, and servo motors with 200 step encoders. I have not changed anything in the servo system. The unit's in mach2 are set at 1000 currently.
I thought I remembered the old PC's Units to be set at 2000, because 10 turns of motor = 1 inch of bed movement, times 200 step encoders =2000, but when I set my laptop to 2000 the bed moves twice as far per command than it should. Remember I have not changed my servo drives, I am not micro stepping, IM not sure if they will micro step. Even when jogging X back and forth at .1 I get (.099 / -.001) (.101 / 0.0) Etc. In the Mach DRO's
The old PC always stopped spot on the number.
Thanks,  Scott.

Offline Hood

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Re: Please help
« Reply #1 on: November 04, 2008, 07:17:25 AM »
Do the DROs correspond to the distance moved? Laptops can be bad news , try doing the optimisation steps paying particular attention to power saving options.
 You wont get too much help with Mach2 I am afraid as I would think most people are using Mach 3 now, might be a good time to try it.
What count encoders do you have? thats what determines the Steps per Unit required in a servo system.
Hood