Use Of Load Power Supplies - Siemens SIMATIC S7-1500 System Manual

3.3

Use of load power supplies

Introduction
The system power supply (PS), central modules (CPU), interface module and input and
output circuits of the I/O modules are supplied with 24 V DC by the load current supply (PM).
Load current supplies can be mounted on the mounting rail but do not have a connection to
the backplane bus.
Observe the installation rules and specified installation distances in the manuals of the load
current supplies.
Use of multiple load current supplies
Several load current supplies (PM) can be used as follows for higher output currents:
● Parallel connection of two load current supplies
● Every load current supply feeds independent 24 V DC load lines.
Alternatively an external 24 V power supply from the SITOP spectrum can be used.
Figure 3-9 Supply of the modules from 24 V DC load current suppl
Note
Alternative 24 V supply of the modules from the control cabinet
If safe galvanic isolation (SELV/PELV to IEC 60364-4-41) is ensured, you can supply the
modules alternatively with 24 V DC from the control cabinet.
Reference
More information on load current supplies can be found on the Internet
(https://mall.industry.siemens.com) in the online catalog and in the online ordering system.
Automation system
System Manual, 12/2014, A5E03461182-AC
Application planning
3.3 Use of load power supplies
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