Cabinet 1
Cabinet 2
Incorrect
Power supply
Drive
Device
PLC
EBS
Device
Device
Incorrect
Figure 4-20
Equipotential bonding (EBS = Equipotential bonding strip)
The better the equipotential bonding in a plant, the smaller the chance of interference due to
fluctuations in potential.
Equipotential bonding should not be confused with protective earthing of a plant. Protective
earthing prevents the occurrence of excessive contact voltages in the event of equipment faults
whereas equipotential bonding prevents the occurrence of differences in potential.
4.6.9
Cable shielding
Signal cables must be shielded in order to prevent coupling of interference.
The best shielding is achieved by installing the cables in steel tubes. However, this is only
necessary if the signal cable is routed through an environment prone to particular interference.
It is usually adequate to use cables with braided shields. In either case, however, correct
connection is vital for effective shielding.
The following generally applies:
• For analog signal cables, the shield has to be connected at one end on the receiver side
• For digital signals, the shield has to be connected to the enclosure at both ends
• Since interference signals are frequently within the HF range (> 10 kHz), a large-area HF-
proof shield contact is necessary
Planning the RF300 system
4.6 Guidelines for electromagnetic compatibility (EMC)
SIMATIC RF300
System Manual, 02/2021, C79000-G8976-C345-09
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