Fig. 13 Ethercat Topology - Beckhoff BK11 0 Series Documentation

Basic principles
Topology
Line, tree or star: EtherCAT supports almost any topology. The bus or line structure known from the
fieldbuses thus also becomes available for Ethernet. Particularly useful for system wiring is the combination
of line and junctions or stubs. The required interfaces exist on the couplers; no additional switches are
required. Naturally, the classic switch-based Ethernet star topology can also be used.
Fig. 13: EtherCAT Topology
Maximum wiring flexibility:
with or without switch, line or tree topologies, can be freely selected and combined.
Wiring flexibility is further maximized through the choice of different cables. Flexible and cost-effective
standard Ethernet patch cables transfer the signals in Ethernet mode (100Base-TX). The complete
bandwidth of the Ethernet network - such as different optical fibers and copper cables - can be used in
combination with switches or media converters.
Distributed Clocks
Accurate synchronization is particularly important in cases where spatially distributed processes require
simultaneous actions. This may be the case, for example, in applications where several servo axes carry out
coordinated movements simultaneously.
The most powerful approach for synchronization is the accurate alignment of distributed clocks, as described
in the new IEEE 1588 standard. In contrast to fully synchronous communication, where synchronization
quality suffers immediately in the event of a communication fault, distributed aligned clocks have a high
degree of tolerance vis-à-vis possible fault-related delays within the communication system.
18 Version: 4.1 BK11x0, BK1250