Application planning
5.2 System and load power supply
Procedure
To set up the supply by means of the CPU/interface module and system power supply, follow
these steps:
1. Open the "Properties" tab of the CPU/interface module in STEP 7 and select the "System
power supply" in the navigation.
2. Select the option "Connection to supply voltage L+".
Figure 5-7
Infeed via system power supply only
As a further possibility you can supply the required power to the backplane bus using only a
system power supply (in slot 0). In this case, the CPU/interface module is not supplied with
24 V DC, and draws its supply from the backplane bus. The system power supply must be
inserted to the left of the CPU/interface module for this.
In general, you can use system power supplies with AC or DC infeed for the configuration.
If no supply voltage with 24 V DC is present (and e.g. only CMs/CPs are inserted next to the
CPU), you can use a system power supply with 230 V AC because the CMs/CPs are supplied
via the backplane bus.
Procedure
To set up infeed only via the system power supply, follow these steps:
1. Open the "Properties" tab of the CPU/interface module in STEP 7 and select the "System
power supply" in the navigation.
2. Select the option "No connection to supply voltage L+".
Figure 5-8
116
Supply voltage via the CPU/interface module and system power supply
No infeed into the backplane bus by means of the CPU/interface module
Automation system
System Manual, 01/2023, A5E03461182-AK