DIY CNC Mill - Random Limit Switch Errors

I think I got it! 
I tried moving the AC lines by the BOB, but that didn't work, probably because I didn't move them far enough. Last night I added a ferrite on the AC lines, and I was able to run the program without failing. This morning I removed the earth ground because it was temporarily through my window, and ran the program again. It did fail. 
When I started building it I had installed an EMI filter on the main power coming in, before the breaker box. I now realize that anything coming in is negligible compared to what the VFD produces. So I moved the filter to the VFD 220v lines. I think that fixed it! I have now run the program three times without fail! (see pic)

Thank you everyone for your help!

For those looking at this later, here is what I learned:

• Interference is a BIG ISSUE
• Separate AC and DC lines as much as possible
• Use shielding on low voltage signal lines (maybe fine without if 24v)
• Use a shielded spindle cable and keep it short! 
• Ground all shielding, but only at one end
• Avoid ground loops - only have one ground connection for each component
• Use ferrites/EMI filters on the lines coming in and out of the VFD - this solved my problem!
• Ferrites may help stop interference - try putting them if other things don't work

Do these things from the beginning! It will save you a huge headache.

zippoffs wrote:

I think I got it! 

• Use ferrites/EMI filters on the lines coming in and out of the VFD - this solved my problem!

I'm happy to hear of your success! 
I want to add a clarification to that one bullet point: EMI filters are very good for the input side of VFDs, but don't try them on the output side unless they are listed for such use. The output side of a VFD produces such a high level of harmonics, a common emi filter will smoke. Ferrites are fine for input and output side.