Re: Interface for CNCPro, etc.

power the optoisolated side with a dc-dc converter with at least 3000 volt
isolation and avoid having a separate power supply on the isolated side, use
high iso voltage optos, and lay out the board with plenty of inter-trace
spacing and maybe even a guard trace. Piezo spark lighters as used on gas
grills make good isolation testers... just don't cook your PC during the
testing.

Layout is critical!!!

Jim Fackert

> 2. If you are going to have meaning full opto-isolation, you need two

independent supplies for the opto board, one using the computer power side,
one using the load power side. I have seen several examples were the load
side was powered from the PC.... I assume that you already know that.