Irregular Actuation and Sampling in a Networked Control System over Profibus-DP

Networked control systems are a special kind of control loops in which the main feedback is closed through a shared communication link. A number of undesirable influences appear when the link to communicate controller and plant is not always available. The aim of this paper is to analyze one of the drawbacks of these systems, irregular conversions that appear when different sampling periods are used in emitter, medium and receiver of the communication. A simulation model is developed to study this irregular conversions and to be employed on the design of control strategies