Study on the network delay of periodic information in the NCS based on EPA

The network delay of the periodic messages transmission in the network control system （NCS） based on Ethemet for plant automation （EPA） is analyzed from the theoretical and experimental perspective in this paper. The composition and the characteristics of the network delay of EPA periodic messages transmission in a subnet is studied through analyzing the information transmission regularity and EPA deterministic scheduling mechanism. On this basis, the queuing delay at communication schedule management entity （EPA _ CSME） that is the most important component of network delay is analyzed, during which the formulas for the queuing delay of periodic messages and other real time parameters are proposed. Furthermore, an experiment is developed to test each component of network delay of periodic messages transmission in a EPA subnet. According to the experimental and the theoretical analysis, the conclusion is drawn that the delay during which the periodic messages wait for the periodic messages transmission time slice is the main factor that causes considerable network delay, and improvement method is presented.

The network delay of the periodic messages transmission in the network control system (NCS) basedon Ethernet for plant automation (EPA) is analyzed from the theoretical and experimental perspective inthis paper. The composition and the characteristics of the network delay of EPA periodic messages transmissionin a subnet is studied through analyzing the information transmission regularity and EPA deterministicscheduling mechanism. On this basis, the queuing delay at communication schedule management entity(EPA_CSME) that is the most important component of network delay is analyzed, during which theformulas for the queuing delay of periodic messages and other real time parameters are proposed. Furthermore,an experiment is developed to test each component of network delay of periodic messages transmissionin a EPA subnet. According to the experimental and the theoretical analysis, the conclusion is drawnthat the delay during which the periodic messages wait for the periodic messages transmission time slice isthe main factor that causes considerable network delay, and improvement method is presented.