Performance analysis of the data link layer in the IEC/ISA fieldbus by simulation model

Fieldbus provides a real-time data communication among field devices in the process control and manufacturing automation systems. In this paper, discrete-event simulation model of the 1993 draft of IEC/ISA fieldbus, which is proposed as an international standard of fieldbus network, is developed. The logical behavior of a simplified model of the data link layer protocol of IEC/ISA fieldbus is described by a Petri net model. Using the simulation model, this paper evaluates the network-induced delay in the data link layer of the IEC/ISA fieldbus. In addition, an integrated discrete-event/continuous-time simulation model of fieldbus and distributed control systems is developed. The integrated simulation model is used to investigate the real-time data communication capability of IEC/ISA fieldbus and the effect of network-induced delay on the performance of control system.