Operation On Grounded Infeed - Siemens SIMATIC S7-1500 System Manual

Protection against external electrical influences
The following describes what you must pay attention to in terms of protection against
electrical influences and/or faults:
• The system for discharging electromagnetic interference must be connected to a
protective conductor with a sufficient cross-section for all plants with an S7‑1500R/H
redundant system.
• You must ensure that all supply, signal and bus cables are correctly laid and installed.
• For signal and bus lines, a cable break, wire break or a cross-circuit must not lead to
undefined states in the plant or system.
Protection of redundancy connections against unauthorized access
Protect the redundant connections in a redundant S7-1500H system so that the fiber-optic
cables are protected against unauthorized access, e.g. by spatial access protection.
Reference
Additional information can be found in the function manual, Designing interference-free con­
trollers (https://support.industry.siemens.com/cs/ww/en/view/59193566).
7.2

Operation on grounded infeed

Introduction
Information is provided below on the overall configuration of an S7-1500R/H redundant
system on a grounded incoming supply (TN-S network). The specific subjects discussed are:
• Shut-off devices, short circuit and overload protection in accordance with
– IEC 60364, corresponds to DIN VDE 0100
– IEC 60204, corresponds to DIN VDE 0113
• Load current supplies and load circuits
Grounded infeed
In the case of grounding incoming supplies (TN-S system) the neutral conductor (N) and the
protective conductor (PE) are each grounded. Both wires 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.
Safe electrical isolation (SELV in accordance with IEC 61131-2 or IEC 61010-2-201)
Load current supplies with 24 V DC output voltage require safe electrical separation and
voltage limiting (extra low voltage). Load current supplies with a 24 V DC output voltage are
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
7.2 Operation on grounded infeed
Wiring
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