Siemens SIMATIC S7-400 Hardware And Installation Manual page 76

Wiring the S7-400
Configuration with Isolated Modules
Shown in Figure 4-4 are the potentials of an S7-400 configured with isolated input
and output modules.
PS
L1
N
PE
Ground bus in cabinet
L +
M
external
24 VDC load current PS
Figure 4-4 Simplified Representation of Configuration with Isolated Modules
4-14
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Racks
DI
CPU
S7-400 and M7-400 Programmable Controllers, Installation Manual
DO
U
internal
Data
Reference
potential M
L1
N
230 VAC load current PS
C79000-G7076-C424-01