Operation Of The Io Device On A Grounded Power Supply - Siemens SIMATIC ET 200SP HA System Manual

Wiring

6.3 Operation of the IO device on a grounded power supply

6.3 Operation of the IO device on a grounded power supply
Introduction
This section provides information on the overall configuration of an IO device based on the
ET 200pro distributed I/O system on a grounded power supply (e.g. TN-S network). The
specific subjects discussed are:
● Disconnecting devices and short-circuit and overload protection according to IEC 60364
(corresponds to DIN VDE 0100) and IEC 60204 (corresponds to DIN VDE 0113)
● Power supplies and load power circuits
Grounded incoming supply
In the case of grounded incoming supplies (TN-S system) the neutral conductor (N) and the
protective conductor (PE) are each grounded. Both conductors form a part of the overvoltage
concept. When a plant is in operation, the current flows across the neutral conductor. When a
fault occurs, for example, a single ground fault between a live conductor and ground, the
current flows through the protective conductor.
Installing the IO device with ungrounded reference potential
To discharge interference current, the reference potential of the interface module and terminal
blocks TB..D must be connected via an RC combination (IM: R = 10 MΩ / C = 100 nF, TB...D:
R = 10 MΩ / C = 4 nF) to the rail (protective conductor).
● This configuration conducts high-frequency interference currents and prevents static
charges.
● An ungrounded configuration of the IO device is always possible since there is no fixed
ground connection on the IO device. The power supply used (power pack / power supply
module / battery) for 24 V DC must also be ungrounded and electrically isolated.
If you want to install the IO device with grounded reference potential, electrically connect the
1M connector to the protective conductor.
Short-circuit / overload protection
Various measures as protection against short-circuits and overloads are required for setting up
a full installation.
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ET 200SP HA Distributed I/O system
System Manual, 08/2019, A5E39261167-AD