Quote Originally Posted by eurikain View Post
Also, If I understand well the wiring you explain and look at the documentation as well, it seems that you're connecting them as PNP type sensor and that blue connects to both 24V PSU GND pin and BOB's input terminal's GND pin ? Is it not an issue that they share they share the same GND though they are circuits operating at different voltages ? I guess GND is GND, doesn't matter the voltage ? I like to fully understand things, that's why I ask ;)
You may connect all your DC 0 volt (GND) lines to ground/earth. There is no problem. Sometimes it helps solve interference issue but most of the time it doesn't really matter if you have them floating or not.

What is you BoB model?