Siemens SIMATIC S5-115U, User Manual

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S5-115U Manual Technical Description
2 Technical Description
This chapter describes the design and principle of operation of an S5-115U with accessories.
2.1 Modular Design
The S5-115U consists of various functional units that can be combined to suit the particular pro-
blem.
Figure 2-1. The S5-115U (Central Unit)
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The numbered information below briefly describes the most important components of the
S5-115U.
Power Supply Module (PS 951)
The PS 951 power supply module generates the operating voltage for the PLC from the
120 V AC/230 V AC or 24 V DC power system voltages. This module uses a battery or an
external power supply to back up the RAM.
The PS 951 power supply module also performs monitoring and signalling functions.
EWA 4NEB 811 6130-02b
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