Today, EtherCAT is one of fastest real-time capable field bus systems. It supports network structures with and without cable redundancy. This paper describes the automatic device scan (online configuration) as observed in a network without cable redundancy using standard EtherCAT components. Based on this, a novel method is presented to automatically scan for devices in networks with cable redundancy. The new method adds the possibility to detect redundancies within the network, may reduce the probability of errors and increases the usability.