Siemens SIMATIC ET 200AL System Manual page 41

5.3 Operation of the ET 200AL on grounded/non-grounded infeed
Introduction
Information is provided below on the overall configuration of an ET 200AL distributed I/O
system on a grounded incoming supply (TN-S network). The specific subjects discussed are:
• Disconnecting devices, short-circuit and overload protection to IEC 60364 (corresponding
to DIN VDE 0100) and IEC 60204 (corresponding to DIN VDE 0113)
• Load current supplies and load circuits
• Supply voltages of the ET 200AL distributed I/O system
Grounded infeed
In grounded incoming supplies, the neutral conductor of the supply system is grounded. A
simple ground fault between a live conductor and ground or a grounded section of the plant
causes the protective devices to trip.
Supply voltages
Provide the ET 200AL distributed I/O devices with a SELV/PELV supply voltage for 1L+.
The supplied SELV/PELV load voltage for 2L+ can be switched, depending on the application.
• 1L+: Supply voltage (non-switched)
• 2L+: Load voltage (switched)
Safe electrical separation (SELV/PELV)
Mains devices/power supply modules with secure electrical separation SELV/PELV are required
for the operation of the ET 200AL distributed I/O system. These power supplies/power supply
modules must comply with IEC 61010-2-201.
The wiring of SELV/PELV circuits must be separated from the wiring of non-SELV/PELV circuits.
Alternatively, the insulation of all conductors must be dimensioned for the higher voltage.
NOTICE
Operation in damp/wet environments
When operating in a damp/wet environment, other voltage limits apply for SELV/PELV
according to IEC 61010-2-201.
Configuring ET 200AL with grounded reference potential
When configuring the ET 200AL distributed I/O system with grounded reference potential,
occurring interference currents are discharged into functional earth. The connections must
be externally connected (connection between 1M and FE).
Distributed I/O system
System Manual, 08/2021, A5E31861578-AJ
5.3 Operation of the ET 200AL on grounded/non-grounded infeed
Connecting
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