Application Planning
4.1 Secondary electrical conditions
NCU 7x0.2
30 Manual, 02/2011, 6FC5397-0AP20-0BA0
4.1.2 RI suppression measures
In addition to the protective grounding of system components, special precautions must be
taken to ensure safe, fault-free operation of the system. These measures include shielded
signal lines, special equipotential bonding connections, and isolation and shielding
measures.
Shielded signal lines
● For safe and smooth operation of the system, the specified cables must be used. Please
refer to the chapter titled Connection.
● For digital signal transmission, the shield must have a conductive connection at both
sides of the housing.
Cable definitions
● Signal cables (example)
– Data cables (Ethernet, PROFIBUS, PROFINET, sensor cables, etc.)
– Digital inputs/outputs
– EMERGENCY OFF lines
● Power cables (example)
– Supply voltage 1 x 230 V AC or 3 x 400 V AC
– Motor cables
Rules for routing cables
In order to maximize noise immunity for the complete system (controller, power section,
machine) the following EMC measures must be observed:
● A minimum distance of 200 mm is to be observed between the signal lines and power
cables.
● If necessary, signal and load cables may cross one another (if possible, at an angle of
90°), but must never be laid close or parallel to one another.
● Only use cables approved by Siemens for the signal lines from and to the Control Unit.
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