Grounding An S7-1200 System - Siemens SIMATIC S7 Functional Safety Manual

You must evaluate every control point for the threat level and consequences of failure. Your
installation can require safeguards that are independent of the S7-1200 to achieve an
appropriate level of risk for personal injury or equipment damage.
Control devices can fail in an unsafe condition, resulting in unexpected operation of
controlled equipment.
Such unexpected operations could result in death, severe personal injury, and property
damage.
When using fail-safe I/O, design safety-related control functions to account for the
probability of faults, including redundancy to achieve an appropriate level of risk for the
consequences of failure.
When using standard I/O, always include an emergency stop function, electromechanical
overrides, or other redundant safeguards when a failure could cause personal injury or
significant property damage.
4.3.2

Grounding an S7-1200 system

Guidelines for grounding the S7-1200
The best way to ground your application is to ensure that all the common and ground
connections of your S7-1200 and related equipment are grounded to a single point. This
single point should be connected directly to the earth ground for your system.
All ground wires should be as short as possible and should use a large wire size, such as 2
mm
When locating grounds, consider safety-grounding requirements and the proper operation of
protective interrupting devices.
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
WARNING
(14 AWG).
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Fail-Safe CPU and signal module (SM) installation
4.3 Control system wiring guidelines
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