End-to-End Delay Evaluation of Industrial Automation Systems Based on EtherCAT

In industrial automation, EtherCAT is a real-time communication protocol widely employed in the local computer networks for fast and predictable data communication between system processes. End-to-end delay is a key performance indicator to industrial applications as it reflects the real-time capability of the system. This paper explores end-to-end delays of EtherCAT-based control systems under different schemes of synchronization, including free-running, frame-driven and clock-driven schemes. A simulation study is presented to assess the delays using various schemes. Simulation results demonstrate that free-running and frame-driven approaches could be adopted in traditional automation applications, while clock-driven scheme can be advantageous in networked control systems where deterministic data communication is required.