Fieldbus brings protocol to process control

Recognizing the harvest to be reaped from a standardized interface for interconnecting their wares, the makers of electronic test and measuring instruments long ago devised the arrangement now known as the Standard Digital Interface for Programmable Instrumentation, or IEEE Standard 488. Movers and shakers in the world of process control saw things differently, as a consequence, that industry still lacks a common digital interface for connecting field devices (pumps, valves, temperature transmitters, and so on) to a system controller. This state of affairs is about to change. For a variety of business reasons, companies now appear ready to embrace an industry-wide standard for what has become known as a fieldbus-an all-digital communication network for connecting process instrumentation to controllers. Many candidate systems are under development, indeed some are in use outside the formal standards process. One bus, however, looks well positioned to become an industry standard-the Foundation fieldbus (trade-marked as the FOUNDATION fieldbus). Still under development by the Fieldbus Foundation, Austin, Texas, it has a particular focus on interoperability. Key functional aspects of the Foundation fieldbus ensure that compliant field devices can easily share data and execute standard functions in a control system