Hi,

I run a K2 CNC router with Campbell designs breakout board and gecko drives with Mach3. 

Sometimes when I run a program, The machine rezeros part way through the program (only after my 4th M zero pause for screwing the work down)  This doesn't happen every time only once in a while, even with the same G-Code.  Could this be noise in my wiring.  I have shielded wires but I haven't grounded the shielding to anything.  Where should I connect the shielding to? (the machine frame? the ground on the breakout box enclosure?)

Thanks for any help,

Ron

When you say rezeros, do you mean the axis physically move to the zero position or just the DROs change to zero?
 Either way it might be worth swapping out your keyboard as this could be a source of the problem.
 As for grounding your  shielding,  best bet is to do it at one end of the cable only and try and ground all cables to the same point. Also it is usual to ground at the control cabinet rather than the machine.
Hood

I suppose I shouldn't say it re-zeros,  it offsets by about 1" positive on the Y axis.  funny you should mention the keyboard,  it's a wireless keyboard and mouse,  perhaps they go out of range and upon getting back into range they mess things up.