Siemens Simatic S7-1500 Manual page 86

Wiring
4.3 Terminal and block diagrams
The figure below shows the current flow with correct wiring.
Figure 4-14
With correct wiring, the supply current flows from the power supply 2L+ via terminal 29 to the
module. In the module, the current flows via the output driver and exits the module via
terminal 40.
86
Current flow with correct wiring using the digital on-board I/O X11 as an example
CPU 1512C-1 PN (6ES7512-1CK00-0AB0)
Manual, 09/2016, A5E35306440-AB