Design and evaluation of real-time communication for FieldBus-based manufacturing systems

It is well known that the ability to support predictable interprocess communication is of great significance to computer-integrated manufacturing and process control systems. In this paper, we propose a strategy for an industrial standard, the SP-50 FieldBus, to support both intracell and intercell real-time communications. We first describe our strategy in detail and show that it is compatible with the current FieldBus draft standard. Under our strategy, the capacity of each link is divided into two parts, The first part is managed by the local link active scheduler for intracell (intralink) communication. The second part is managed by a proposed global network manager for intercell (interlink) communication. By dividing the link capacity in this way, our strategy allows for fast local intracell connection establishment, while supporting global intercell connections. Using two examples, one for typical manufacturing systems and the other for multimedia networking, we also demonstrate the power and utility of the proposed strategy as compared to token-passing protocols.