Lenze E84AYCEC - Manual (Page 27)

EDS84AYCEC EN 3.0 - 09/2012
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E84AYCEC communication manual (Ethernet POWERLINK)
Installation
Electrical installation
5.2.2 Network topology
[5-4] Network topology for Ethernet POWERLINK
Inside the segment only Ethernet hubs may be used as infrastructure elements. The hubs
must meet the requirements on class II repeaters acc. to IEEE 802.3u.
For this purpose Lenze offers the dual hub integrated into the communication module and
the separate eight-fold hub, type E94AZCEH.
Class I hubs and switches are not permissible since they have considerably longer delay
times for the frame forwarding and a bigger jitter. Both sizes reduce the real-time
capability and dynamics.
The cable length between both nodes is limited to 100 m.
The topology rules (IEEE 802.3u) required for controlling the collisions may be violated in
the EPL network segment since according to the EPL access order frame collisions are
prevented. This enables a structure of lines and any hybrid forms between star and line
topology.

Note!
The use of class I hubs and switches inside the EPL network segment is not
permitted.