
● Rout signal cables and data cables separately from the power cables.
–
Separate cable ducts or cable bundles.
–
The distance should be 20 cm or greater.
● Lay signal and data cables close to earthed surfaces.
2.4.4.3
Cable Shields
● Use only shielded data cables. The shield should be earthed at both ends.
A cable shield only earthed at one end can only protect from capacitively coupled interfer-
ence and low-frequency disturbances (50 Hz hum).
● Avoid parasitic currents flowing through the cable shields.
This can be done by installing current-carrying equipotential bondings.
● Use only cables with braided shields.
Foil shields are not robust enough, cannot be contacted well and have poor HF properties.
● Use only metallic or metal-plated plugs for shielded data cables.
● Use only shielded cables for analog signals.
For small signals earth the shield only at one end.
● Earth the cable shield directly with a clip when entering the switch-gear cabinet.
Do not cut the shield until the cable reaches the module connected.
The connection between the PE bar and the shield bar must have a low impe-
dance.
2.4.4.4
Switch-Gear Cabinet
The connections between the switch-gear cabinet, the mounting plates, the PE bar and the
shield bar must have a low impedance.
Earth the switch-gear cabinet doors with short and highly flexible conductors.
Only use filament lamps (bulbs) or fluorescent tubes with interference suppression.
Use the mains socket which is located inside the switch-gear cabinet.
Chapter 2.5.2.1 “Switchgear Cabinet Assembly” on page 1196
2.4.4.5
Reference Potential
● Provide a uniform reference potential in the entire installation and earth all electrical appli-
ances if possible.
● Route your earthing conductors in a star configuration so that no earth loops can occur.
2.4.4.6
Equipotential Bonding
The Installation of equipotential bondings are necessary if there are present or expected poten-
tial differences between parts of your application.
Connections
Earthing
Illumination
For supplying
the PC
System Assembly, Construction and Connection
Overall Information (valid for complete AC500 Product Family) > EMC-Conforming Assembly and Construction
2019/04/17
3ADR010121, 13, en_US
1188