NORD Drivesystems BU0270 - Manual (Page 66)

Supplementary Manual EtherCAT for NORDAC SK 200E
66 Subject to technical amendments BU 0270 GB
8 Additional information
8.1 Bus configuration
In an industrial environment the correct installation of the bus system is particularly
important in order to reduce potential interference. The following points are designed to
help prevent interference and problems right from the start. The installation guidelines are
not complete and applicable safety and accident prevention guidelines must be complied
with.
8.1.1 Laying the EtherCAT bus cable
An EtherCAT network can consist of an almost unlimited number of participants. In can be set up as a linear
structure (NORD standard), as a tree structure, or as a ring system. There are practically no restrictions to the
extent of the network, as each participant functions as a repeater and amplifies the bus signal. Only the
distance between neighbouring participants is limited to 100m.
8.1.2 Cable material
Copper cables should be used for the bus. The cables must at least fulfil the Ethernet standard CAT-5.
8.1.3 Cable layout and shielding (EMC measures)
If EMC measures are not in place, high-frequency interference which is mainly caused by switching processes
or lightning often causes electronic components in the bus participants to be faulty and error-free operation can
no longer be ensured.
Correct laying of the bus cable dampens the electrical influences which may occur in an industrial
environment. The following points must be observed:
• Implement long connections between bus participants by the shortest possible distances.
• Connect each SK TU4-ECT to the PE.
• Only use plugs with a metal housing.
• For the production of EtherCAT cables, lay the shielding on as wide an area of the plug as possible.
• With the parallel installation of bus cables, a minimum distance of 20 cm from should be maintained from
other cables carrying a voltage greater than 60V. In particular, this must be observed for cables to motors
or chopper resistors. This applies to lines laid both inside and outside of control cabinets.
• The minimum distances for parallel installation may be reduced by shielding cables carrying voltage or by
means of earthed metal dividers in the cable ducts.
Special attention should be paid to bending radii:
Fixed cable Freely laid cable Bending radius of cable
Minimum radius
5 x cable diameter
Minimum radius
10 x cable diameter
Correct Incorrect
NOTE
If earthing potential values are different, transient current may flow through shielding which
is connected on both sides. This may be a danger to electronic components. Differences in
potential must be reduced by means of adequate potential equalisation.