Fieldbus technology: a solution for multiplexing plant signals?

The specification requirements for designing a complete distributed system in the instrumentation and process control environment are not well known. In this paper we present the specification requirements in order to design the distributed systems. Distributed control by using fieldbus technology is only the first step to the application of intelligence in the field devices. We review the fieldbus technology, state the current status of the international fieldbus standards and differentiate conventional local area networks from the fieldbus technology as both are used in the distributed systems. Then some of the standard fieldbuses with their characteristics are described. In the distributed systems optimisation of response time plays a important role at the time of designing the control architecture. We propose a channel division multiplexing method in order to optimise the response time. Finally we explain what the distributed systems are really demanding from the fieldbus technology