Network system, network terminal, and method for specifying location of failure in network system

摘要

In a network of a topology of a loop and a bus, occurrence of a failure is detected and a location of the failure is specified. Occurrence of the failure is detected by detecting that a specific signal pattern to be received at regular time intervals within a fixed time period is not received. A node which has detected occurrence of the failure transmits or receives a specifying signal among the nodes, and decide whether or not the failure has occurred adjacently to itself. A packet indicating a decided location of the failure is transmitted or received among nodes, and thereby respective nodes specify the location of the failure. When the failure has occurred at the master node, a node having a smallest node ID after waiting time according to the node ID operates as the alternative master node.