A Real-Time Approach to Process Control, 3rd Edition

Appendix C

New Capabilities with Control Technology Hardware and Software

C.1 Foundation Fieldbus for Instrumentation and Control

In the mid-1990s, significant advances in microprocessor technologies made possible the development of field-based electronic devices that led to a revolution in field instrument communications. The move to an all-digital communication protocol was pushed by the need to access the wealth of diagnostic data and advanced functions now possible in these enhanced field devices. Several technologies came together in what is now called Foundation Fieldbus (FF).

The primary benefit of a completely digital communication bus is the ability to access multiple variables available from more powerful devices and to use these for control applications, reducing the number of devices needed to implement various control strategies. The FF supports a deterministic communication that allows devices to communicate directly to each other in order to perform closed loop control, independently of the control system to which it is connected. With multiple devices connected to a common bus, or segment, the installed wiring costs of the instrumentation are reduced, along with cabinet footprint. Each segment can host a mix of input and output devices, removing the need for rationalizing I/O signals to dedicated card types, thus reducing the design costs of the physical I/O.

Since its introduction, FF has seen a steady increase in adoption as users realized the benefits of this ...