Siemens SIMATIC S7-1500 System Manual page 236

Power segment overview with redundant system power supplies for the H-CPUs
Recommended configuration variant with redundant system power supplies and a
maximum of four CPs
In a configuration with redundant system power supplies, the power is fed in via the two
system power supplies. The power supplied by both system power supplies must be at least
twice the power drawn by the active backplane bus, H-CPU, and CPs. The result can be seen
in the power segment overview in STEP 7.
Example: In the following configuration variant, the two system power supplies
PS 60W 120/230 V AC/DC feed the power of 120 W into the power segment. The active
backplane bus, H-CPU, and 4 CPs are supplied via the supplied power (-53 W). In the event of
a PS (-60 W) or supply voltage failure, the remaining power (120 W - 53 W - 60 W = 7 W) is
still greater than the power drawn. The power balance is positive (+7 W).
Figure 6-69
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
Power segment overview with redundant system power supplies
Application planning
6.8 System power supply
235