Evaluating the field bus data link layer by a Petri net-based simulation

The performance of the data link layer of the field bus, an emerging LAN architecture for control systems presently under standardization, is discussed and evaluated. Some aspects of the communication mechanism are presented, referring to the use of the two kinds of tokens of the protocol and pointing out their main features and the advantages and disadvantages offered by each one. The protocol was specified by extended timed Petri-nets and was evaluated by a suitable simulation tool. The results provide some criteria according to which the designer can choose, among the various mechanisms made available by the standard proposal, those which provide the most efficient solution for the scenario being considered