I asked a question about wiring a galil 1900 board on the Galil forum and I'm puzzled by the caution statement at the end of the responce
http://www.galilmc.com/cgi-bin/ubb/u...c;f=1;t=000408

I'll explain my wiring concept. I use supply 24 volt DC to all input switches whever posssilbe. Then from the switch to the Opto input. From the other connection on the opto input, a wire is run to the dc common terminal block. Most switches are wired NC.


Does this have a weakness in opto isolation?

Karl