Abstract: In the initial phase, the master device is configured to disable the connection between the junction device and the last slave device before performing the EtherCAT distributed clock synchronization procedure. After completion, the connection between the junction device and the last slave device is enabled. When a disconnection occurs in a closed loop topology, the junction device can serve to provide a redundant path for forwarding datagrams, thereby achieving cable redundancy. After the disconnection is fixed, the system time delay of each slave device calculated during the initial phase can still be applied without needing to perform again the distributed clock synchronization procedure.