System And Load Power Supply - Siemens SIMATIC S7-1500 System Manual

4.2

System and load power supply

In the S7-1500 automation system, you must make a distinction between two different power
supplies:
● System power supply (PS)
● Load current supply (PM)
Figure 4-2 Total configuration with load current supply (PM) and system power supply (PS)
Optionally, you can insert up to two system power supplies (PS) in the slots to the right of the
CPU (power segments).
System power supplies
● PS 25W 24V DC: Supply with 24 VDC and 25 W of power
● PS 60W 24/48/60V DC: Supply with 24/48/60 VDC and 60 W of power
● PS 60W 120/230V AC/DC: Supply with 120/230 VAC and 60 W of power
S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB
The system power supply has a connection to the backplane bus (U-connector) and
supplies solely the internally required system voltage for the backplane bus. This system
voltage supplies parts of the module electronics and the LEDs. A system power supply
can also supply CPUs or interface modules if these are not connected to a 24 VDC load
current supply.
The load current supply feeds the module's input and output electric circuits. In addition,
you need a load current supply in order to supply the CPU and the system power supply
with 24 VDC. The supply of the CPU with 24 VDC is optional if you supply the voltage for
the backplane bus via a system power supply.
If you are using load current supplies, we recommend the devices from our SIMATIC
series PM 70W 120/230V AC or PM 190W 120/230V AC. These devices can be mounted
on the mounting rail.
The load current supplies listed below have been technically adapted especially to the
S7-1500 automation system. Use of the listed load current supplies
(PM 70W 120/230V AC and PM 190W 120/230V AC) is not imperative because a SITOP
module, for example, can be used as an alternative.
Application planning
4.2 System and load power supply
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