I have attached a photo of how I have the VFD wired. The 220v from the wall has three wires. I have the two hots going to 'R' and 'S' on the left and the Ground going to the ground point on the far right side. The wire is not shielded from the wall as it is just a modified extension cord. The wire going out to the Spindle from the VFD is shielded, it is not connected to anything on the spindle end and when I connect it to the same ground lug on the far right you see in the picture on the VFD end it throws a "Limit Switch Triggered" error in Mach3 as soon as I start it up. Again, the VFD is completely isolated from anything else on the machine, it is not wired anywhere near the control box, to the PC or anything... If I disconnect the shielding from the ground lug than I do not get the limit switch error unless I disconnect the PC side ground from earth ground as explained below...
Okay, so the other issue causing "Limit Switch Triggered" error is if I don't have the PC side 5v connected to the controller box earth ground. I thought that I was supposed to isolated the PC power from the ground used by the A/C and toroid but if I do I get the limit switch triggered error (with no further details). Here is my setup, perhaps it will be obvious to one of you where my problem lies:
1. I have 5vdc from the Computers USB port going to the C10 control board to power it.
2. I have 12vdc from the Computers Power Supply going to the Opto22 relay in the control box to turn on 120v AC power to the toroid.
3. The limit switch shielding is all bundled in the box side together and attached to the earth ground bar coming from the wall A/C
4. The 5vdc from the Computers USB port has the ground wire also connected to the control box ground bar (if it is not, I get the "Limit Switch Triggered" error as soon as I turn on the VFD)
Also, it probably goes without saying but when I get these "Limit Switch Triggered" errors there is not actually limit switches that are triggered on on diagnostics page...
Hope these details are enough to help. Thanks!