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

Application planning
4.2 System and load power supply
4.2.2 Special considerations for the use of a system power supply in the first power
segment
There are three options for the infeed of the required system voltage in the backplane bus:
● Infeed via CPU
● Infeed via CPU and system power supply
● Infeed via system power supply only
Infeed via CPU
Infeed via the CPU generally suffices for small and medium hardware configurations. The
power consumption of the connected modules must not be greater than 10 or 12 W
(depending on the CPU used).
In this configuration variant, supply the CPU with 24 VDC from a load current supply.
Parameter assignment of the CPU: In STEP 7, select the "Connection to supply voltage L+"
option in the "Properties" tab in the "System power supply" area navigation so that STEP 7
can calculate the balance correctly.
Figure 4-4
40
Supply voltage via CPU only
S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB