A distribute-merge switch for EtherCAT networks

EtherCAT is a popular industrial Ethernet solution conceived mainly for connecting control applications to remote I/Os. Because of its high communication efficiency - that achieves cycle times well below 1ms-it can be profitably adopted for motion control systems as well, which are known to have tight timing constraints. In this paper, a solution is introduced and described that is based on a suitable switch able to operate at the level of single EtherCAT telegrams. Such an approach achieves increased network performance by reducing propagation delays. In addition, a satisfactory degree of compatibility is ensured to the existing EtherCAT devices and applications.