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

Reference
Information about the required lines is available in the section Power balance calculation
(Page 35).
Further information on the performance values (power feed, power consumption) of the
CPU, of the system power supply, and of the I/O modules can be found in the Manuals
(http://support.automation.siemens.com/WW/view/en/57251228) of the respective modules.
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 system power supply:
● 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: Select the "Connection to supply voltage L+" option in
STEP 7 in the "Properties" tab in the "System power supply" area navigation so that the
power balance of STEP 7 can be calculated correctly.
Figure 4-4
S7-1500 Automation System
System Manual, 01/2013, A5E03461182-01
Supply voltage via CPU only
Application planning
4.2 System and load power supply
33