Component based colored Petri net model for Ethernet based networked control systems

This paper presents a novel colored Petri net model for the simulation of fully-switched Ethernet based networked control systems (NCS). The model of the NCS is built from models of the automation system components (e.g. PLC, Ethernet Switch, IO Module) in a structure conserving way. CPNtools software is used to build and simulate the models. The proposed approach is used to study the overall response time of a given NCS as well as the two delays between actuator and controller and between sensor and controller respectively. These delays are often used in the design of controllers for NCS. An analysis of the results using periodograms shows a high amount of regularity in the delays that possibly can be exploited for controller design.