The industry's move toward digital architecture began with Emerson's introduction of HART in the mid 80's.

This hybrid protocol overlays digital information on the traditional 4-20 mA analog signal, providing some of the benefits of an all-digital fieldbus while maintaining compatibility with 4-20 mA control signals and hardware. For example, the added digital information can aid in configuration and commissioning, communicate multiple measurements and calculated values, and provide access to diagnostic messages and historical data.

Although users have been installing HART devices for years, they often haven't taken full advantage of these added capabilities. Now they can -- with PlantWeb architecture. HART I/O in our DeltaV and Ovation systems, together with AMS predictive maintenance software, make it easy to directly access device calibration, configuration, and diagnostic information without additional wiring, external multiplexers, or data mapping.

For more information on HART, visit www.hartcomm.org