When connecting to either Sensor port with an M8 connector to access Pin 2 signal; you typically will use a standard parallel type splitter cable assembly that breaks out each of the available pins on the Module to their own M8 connection port. These splitter cables wire the +24V and Common connections in parallel
Aux I/O Pin 2 as Input
When the Aux I/O Pin 2 is configured as an input, the circuit is NPN/PNP auto-sensing. The signal can be connected to either +24V or 0V to operate.
Aux I/O Pin 2 as Output
When the Aux I/O Pin 2 is configured as an output, the circuit is NPN only and requires the load to be connected to Pin 1 (+24V)