An architecture for flexible scheduling in Profibus networks

Recently, much attention has been given to the need to endow industrial communication networks used in real-time systems with flexible scheduling. This allows control systems to adapt to the variations in the requirements of traffic generated by modifications in the environment of the system, or changes in its structure. Another active area is multimedia transmission in industrial environments. In this paper, a flexible scheduling system for Profibus networks is presented. There are two objectives. Firstly to allow the characteristics of real-time traffic to deal in run time in a fieldbus and secondly to enable the scheduling of video traffic for industrial monitoring purposes. The system proposed allows, with regard to traditional Profibus MAC/scheduling, rapid dynamic adaptation to the new requirements, minimizing the bandwidth necessary for its management and maximizing the use of the available bandwidth. As a result there is an improvement in quality of video sources as well as the number of video sources, which can co-exist with the control traffic, without affecting its QoS.