IEEE Access (Jan 2020)

Accuracy Improvement of Master–Slave Synchronization in EtherCAT Networks

  • Sung-Mun Park,
  • Hyoung-Woo Kim,
  • Hong-Ju Kim,
  • Joon-Young Choi

DOI
https://doi.org/10.1109/ACCESS.2020.2982704
Journal volume & issue
Vol. 8
pp. 58620 – 58628

Abstract

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In the study, we develop a method to improve the accuracy of master-slave synchronization in EtherCAT networks. The method involves two key compensations that are not considered in the EtherCAT protocol. First, the propagation delay between the master and reference slave is measured, and the system time of the reference slave is then compensated for the measured propagation delay. Second, the bias component of the synchronization error between the master and reference slave is periodically estimated, and system time of each slave is then compensated for the estimated bias component. The entire method is implemented as part of the master application without modifying the EtherCAT protocol or requiring excessive computation load or large memory space. Thus, the developed method is advantageous because it can be immediately applied at low cost to existing EtherCAT networks. By performing extensive experiments based on a Linux-based EtherCAT master, we demonstrate that the developed method significantly improves the accuracy of the master-slave synchronization in EtherCAT networks.

Keywords