InTech Case Study on Fieldbus for Steam Drain Control

There is an interesting case study in this month's InTech about using FOUNDATION fieldbus that discusses using a mixed environment of conventional devices and fieldbus devices in a steam drain control application.  the case study also talks about extensive use of fieldbus function blocks and was a collaborative effort between John Petzen of GE and Fieldbus Foundation.

From the article:

"Fieldbus-enabled valves are available that have extended capability, including the capability to interrogate external switches. While these were intended for use with external limit switches for valve position, these valve capabilities provide an interesting solution to the drain-valve control problem laid out above. The level switches can be wired to the valve controller, and switch position can be reported back to the control system using discrete input blocks. While this allows the wiring reduction typically associated with digital device installation, it avoids the higher device and installation cost of level transmitters. "

 Fieldbus for steam-drain control: Combining simple devices and fieldbus devices in a common system