I need to understand the circuit diagram of a Klöckner Moeller relay output unit
The best way is to use part number or model number on manufacturer website.
Relays are designed to either give dry closure or wet closure. The diagram shown seems to give both. A dry closure is one with no voltage or ground connection.
Control is the dotted line on the right. There is a diode between terminals 13 and 14, which will close on activation.
Edit:
Out of curiosity, what are these connected to?