Quote Originally Posted by 1Jumper10 View Post
Im trying to think of all the equipment on my router that is not opto isolated that i have connected directly to my UC4400ETH. The servos are, as I recall the vfd is, so I believe the only thing that leaves is three sensors and a DAC. And I think I remember reading in the uc400 eth manual that's the inputs can sink a maximum of 20 milliamps? And I was careful to make sure that the power converter for the switches and the DAC all share a common ground with the uc400 eth. My point is, I didn't use a breakout board. The breakout board I used was simply an expansion of the connections on the uc400 eth. I could be wrong, but I don't think that a breakout board is absolutely necessary. At least mine's working fine without it right now.
Your servos and VFDs may have optoisolated inputs, but what happens if the wire shorts out to a high voltage source?

The main reason for optoisolated BOBs, is so that if a fault develops in the wiring resulting in high voltage where it shouldn't be, the opto on the BOB gets fried, and not the controller.