DIY CNC Mill - Random Limit Switch Errors

Sorry, I tried uploading pictures of my BOB several times, but it wouldn't do it. I think I got it to work finally.

NWE, even though I have the BOB right next to the contactor and 12v/24v power supplies, I have never had any issues from those. I have consistently been able to run programs without issue with everything except the VFD on. The contactor is part of my Estop circuit, and it only gets turned on before I run a program or off if I hit the Estop. I have only ever experienced issues when the VFD is on.

I experimented yesterday and learned some. I tried connecting it to earth ground, but that did nothing. I tried disconnecting everything from the BOB except for the 24v coming in and the parallel port and USB from the PC (I switched the VFD to manual control). LinuxCNC ran the program with out any trips even though the VFD was running, so the BOB itself can't be the issue. I tried reconnecting one of the stepper driver pulse/direction signal wires (the steppers were completely off) and ran the program again, and it did trip, even though that wire is shielded and grounded.

I will disconnect the second shielding grounding at the motor. I will also try adding ferrites on the VFD wires first. I think we have a couple lying around that we also pulled from other things.