Fieldbus / Wireless

Fieldbus Protocols Support All Processes

Flock of Fieldbuses - The Remaining Fieldbus Protocols May Not Be Getting Glamorous, Hollywood-Style Buzz Anymore, but They're Still Going Strong

By Jim Montague

In the entertainment field, any huge success is quickly followed by the half-joking question, "What have you done for me lately?" This phrase floated up in my memory as I was researching this issue's "Fieldbuses Uplift All Processes" feature article, and I think it was because I've been covering Ethernet, wireless, Internet of Things, virtualized computing and the cloud for so long that I forgot what used to be the biggest news in networking for process control. Well, today's remaining fieldbus protocols may not be getting glamorous, Hollywood-style buzz anymore. However, they're still going strong, though due to Ethernet and wireless, it might seem like they're slightly more behind-the-scenes than in the past.

For instance, BP Chemicals in Lima, Ohio, recently sought to improve the reliability of its process for making 1,4 butenediol (BDO) directly from butane. However, its engineers were concerned that a traditional DCS would concentrate too much logic in its controllers, and that centralizing its DCS logic in a rack room and fanning out hundreds of cables to 4-20mA field devices would create too many control system vulnerabilities, limit process design flexibility and increase expansion, modification and lifecycle costs.

Also Read "Fieldbus: Do Fence Me In!"

To automate their large-scale BDO application, BP's engineers selected a field-based control architecture based on Foundation fieldbus H1 and the DeltaV digital process automation system from Emerson Process Management, and deployed a radial topography for the plant's 71 network and device segments with an average of five or six devices per segment. After gaining experience with their new automation system, the engineers felt comfortable switching to a hybrid, multi-drop fieldbus topology.

Thanks to their distributed, fieldbus-based control system, BP's BDO operators can see control valve positions on their displays with every faceplate and valve icon indicating true position with every scan, which is especially helpful when balancing flows during start-up. Finally, BP's installers were able to commission their fieldbus devices quickly because the devices reported themselves to the automation system as soon as their wires were landed or fastened to their permanent wiring terminals.

Likewise, Asahi Kasei Synthetic Rubber Singapore (AKSS), a subsidiary of Asahi Kasei Chemicals Corp., just finished building its year-old plant on Singapore's Jurong Island. The facility will produce 50,000 tons per year of solution-polymerized, styrene-butadiene rubber (S-SBR), which is a type of synthetic rubber used in "green tires" to improve fuel efficiency and performance. To automate the S-SBR plant's production, AKSS picked Yokogawa Electric Corp.'s Centum VP production control system (PCS), ProSafe-RS safety instrumented system (SIS), Exaquantum plant information management system (PIMS), Plant Resource Manager (PRM) asset management package and a variety of Foundation fieldbus field devices.

Also Read "Busting Myths About Foundation Fieldbus"

"Because we're always striving to introduce useful process control technologies, AKSS decided to use Foundation fieldbus at our greenfield S-SBR plant," says Shuji Yahiro, AKSS' plant general manager. "Used in combination with the PRM asset management package, it allows checking of each loop and control valve signature during the start-up period. During normal operations, operators and engineers can see the status of all field devices from the central control room at any time. This new digital technology is changing how field operators work and will make possible a proactive maintenance approach that will allow AKSS to reduce capital expenditures."

Okay, so it's obvious that fieldbuses never went away. It turns out I was too focused on over-hyped technology trends and wasn't paying enough attention to what was going on in the real world. Sorry, and I'll try to stay more awake and aware in the future.