Siemens SCALANCE M804PB Operating Instructions Manual page 44

Connecting up
5.4 Digital input/output
Digital input
The 2-pin terminal block has the following assignment:
DI+
DI- (input ground)
If there is an adequate switching voltage at the digital input, the digital input is active and the
"DI" LED is lit.
44
24 VDC
-
Operating Instructions, 07/2018, C79000-G8976-C496-01
SCALANCE M804PB