By Robert Rawlyk, Beckhoff AutomationTHERE HAS BEEN a significant movement in recent years to bring Ethernet to the factory floor. Many were predicting the replacement of common industrial fieldbus systems with Ethernet. At present, there are several different Ethernet protocols for industrial automation and communication. The intention of this paper is to explain the differences between Ethernet and the various protocols that are transmitted over Ethernet. In understanding the differences between various protocols and the demands of an application, an automation specialist can determine what protocol(s) would be appropriate for their application. In order to bring Ethernet to the factory floor, it is also important to understand what hardware and knowledge for configuring that hardware is required.