On the Evaluation of Clock Synchronization Methods for Networked Control Systems

A distribute control requires to maintain time synchronization to the degree of precision depending on a particular application domain. Many large distributed systems employ Ethernet or even full TCP/IP stack for communication. Two prevalent protocols are used for clock synchronization in these networks, in particular, Network Time Protocol (NTP) and Precise Time Protocol (PTP). In this short paper, we present a method for practical performance evaluation of clock synchronization within a distributed environment consisting of nodes running a commodity real-time operating system. The results of measurement provide us a hint on the degree of synchronization that can be practically achieved among the set of distributed devices. The main contribution of this paper is to provide a simple method for practical evaluation of synchronization methods for a distributed control system and presenting some preliminary data from the measurement. A complete result set may be used, e.g., for defining a performance estimation functions in a platform-based design approach to networked control systems.