Selecting The Load Power Supply Unit; Characteristics Of Load Power Supply Units - Siemens SIMATIC S7-300 Hardware And Installation Manual

5.9

Selecting the load power supply unit

Load power supply unit
The load power supply feeds the input and output circuits (load circuits), and the
sensors and actuators.
Characteristics
You will have to adapt the load power supply unit to your specific application. The
following table compares the various load power supply units and their
characteristics to help you make your choice:
Table 5-10
Mandatory for ...
Modules requiring voltage
supplies of ”  9'& RU ” 
VAC.
24 VDC load circuits
24 VDC load circuits
48 VDC load circuits
60 VDC load circuits
Requirements
The DC load power supply must meet following requirements:
It must provide an extra-low voltage of ” 60 VDC and be safely isolated from
mains. Safe isolation from mains can be realized, for example, in accordance with
VDE 0100 Part 410 / HD 384-4-41 / IEC 364-4-41 (as functional extra-low voltage
with safe isolation) or VDE 0805 / EN 60950 / IEC 950 (as safety extra-low voltage
SELV) or VDE 0106 Part 101.
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02

Characteristics of load power supply units

Characteristics of the load
power supply
Protective separation
Output voltage tolerances:
20.4 V to 28.8 V
40.8 V to 57.6 V
51 V to 72 V
Configuring
Remarks
These characteristics apply
to Siemens power supplies
of the series PS 307 and to
SITOP power (series 6EP1).
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5-31