Guidelines For Fail-Safe Installation - Siemens SIMATIC C7-613 Manual

2.5

Guidelines for Fail-safe Installation

Overview
Automation systems require appropriate shielding measures in order to prevent
interference. This can only be ensured by enclosed metal installation (cabinet
mounting, for example).
In a system that is not properly bonded to ground or shielded, noise on the internal
controller bus may develop as a result of low frequency (LF) or high frequency
(HF) signals.
Noise may be emitted from switching relays or contactors (high-speed current or
voltage transitions, RF interference), or may develop as a result of equipotential
differences between two plant elements (NF interference).
Note
You can find additional information about construction guidelines in the S7-300
Automation System installation manual.
Usage / routing of interference-proof cables
• Only shielded cables are permitted for all analog signals.
• Always use the standard cables supplied by Siemens.
• Connect both ends of the shielding of the following cables:
– Control signal cables
– Bus cables
– Cables for connecting I/O devices
• Screw-tighten or interlock all connectors.
• Do not route signal cables in parallel to power circuit cables.
Route the signal cables through a separate cable duct, which is installed at a
distance of at least 50 cm away from power cables.
C7-613 Control System
A5E00138934-03
Installing and Wiring the C7-613
2-17