Towards LonWorks technology and its applications to automation

The fieldbus systems in centralized or distributed control systems have been widely used in the area of industrial automation for several years. Among those fieldbus systems, the LonWorks/sup TM/ is becoming regarded as a new promising way to implement the industrial network systems. The LonWorks is a universal control network system developed by Echelon Co. in 1990. In this paper, we introduce a distributed control system for industrial applications based on LonWorks technology and propose the rate-based traffic control of industrial control networks employing LonWorks. The LonWorks network systems is composed of a network node called a LonPoint containing Neuron Chip. Each LonPoint communicate based on LonTalk protocol which is a kind of CSMA/CA protocol. Throughout this paper, we implement the lab-scale LonWorks network system and synthesize a rate-based traffic controller. Basically, the proposed rate-based traffic control system is in closed-loop by utilizing the feedback channel errors, which shows improved performance compared with other industrial control networks commonly operated in open-loop. To this end, an additional network node, called monitoring node, is introduced to check the channel status without increasing the channel load. We demonstrate the improved performance of the controlled network system in view of throughput and fairness measures through the experimentation upon it.