Siemens SIMATIC ET 200AL System Manual page 36

Connecting
5.1 Rules and regulations for operation
Protection against outside electrical influences
Below is a description of what you must pay attention to in terms of protection against
electrical impacts and/or faults:
• For all plants or systems in which the ET 200AL distributed I/O system is integrated, you
must ensure that the equipment or system is functionally grounded to discharge
electromagnetic interference.
• For supply, signal and bus cables, you must ensure that the cable routing and installation
is correct.
• For signal and bus cables, you must ensure that a wire/cable breakage or a cross-wire does
not lead to undefined states of the plant or system.
Reference
Additional information can be found in the function manual Designing interference-free
controllers (https://support.industry.siemens.com/cs/ww/en/view/59193566).
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Distributed I/O system
System Manual, 08/2021, A5E31861578-AJ