Special Considerations For The Use Of A System Power Supply In The First Power; Segment - Siemens SIMATIC S7-1500 System Manual

Reference
Information about the required power is available in the section Power balance calculation
(Page 45).
Additional information on the performance values (power feed, power consumption) of the
CPU, interface module, system power supply, and I/O modules can be found in the manuals
(http://support.automation.siemens.com/WW/view/en/57251228) of the respective modules.
3.2.2

Special considerations for the use of a system power supply in the first power

segment

Infeed options
There are three options for the infeed of the required system voltage in the backplane bus:
● Infeed via CPU/interface module
● Infeed via CPU/interface module and system power supply
● Infeed only via system power supply in slot 0
Infeed via CPU/interface m odule
Infeed via the CPU/interface module generally suffices for small and medium hardware
configurations. The power consumption of the connected modules must not exceed the
power supplied by the CPU/interface module.
In this configuration variant, supply the CPU/interface module with 24 V DC from a load
current supply.
Procedure
To set up the supply by means of the CPU/interface module, 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 3-6
Automation system
System Manual, 09/2016, A5E03461182-AD
Supply voltage via CPU/interface module only
Application planning
3.2 System and load power supply
41