Editorial Comment
Why Fieldbus Technology?Potential benefits of fieldbus have been touted for many years, but products have only recently become available. We have always believed that once several suppliers offered fieldbus products, the technology would gain rapid acceptance. As you will read, the savings in capital, installation, engineering and ongoing maintenance costs are hard to ignore. And the prospect of implementing even lower cost, higher-performance control systems in the future by embedding more control intelligence into field devices ensures the technology will evolve. Since there are now several fieldbus installations in the oil, gas and process industries, we feel the time is right for a publication dedicated to helping users evaluate and implement fieldbus technology. Other field networks. This publication covers what we call "process" fieldbuses. We consider a process fieldbus to be any digital field network that provides bi-directional communication between the devices of a basic process control loop: process variable transmitter (pressure, flow, level, etc.), a final control element (valve, damper, variable-speed motor drive, etc.) and a process controller (distributed control system, programmable controller, PC, workstation, etc.). This distinguishes a process fieldbus from other networks such as "sensorbuses" and "devicebuses" (see R. H. Caro’s article) and is why we have chosen not to include networks such as DeviceNet, Interbus, LonWorks, etc., which are more popular in the discreet parts manufacturing industries. We also did not include articles about the HART protocol, which has been offered by several manufacturers for nearly a decade. While it has the largest installed base, and will continue to grow for many years, a lot of information has already been published about it. Also, since it superimposes a digital signal over existing 4–20 mA signals, many view it as an interim transition from analog to digital field networks. However, it is a technology definitely worth considering for those who want to realize some of the benefits of fieldbus without making the jump to an all-digital network. At this time, the Foundation fieldbus and PROFIBUS protocols seem to have the most oil, gas and process industry installations, and so the articles here are based on them. Most projects to date have been relatively small, but larger projects are on the horizon. For example, a contract for a large process industry fieldbus project was recently awarded by BASF Ludwigshafen to Elsag-Bailey - Hartman & Braun for its new polymer dispersion plant in Germany. This automation contract with Symphony and Harmony includes 500 pressure and differential pressure instruments utilizing a PROFIBUS fieldbus. As more experience is gained with the newer Foundation fieldbus, larger projects will surely follow. Thus, fieldbus is finally beginning to fulfill many of the promises made for it over a decade ago. Call for papers, news, products, etc. Our next Fieldbus Technology supplement is slated for publication in May 2000. We hope to expand our coverage to include news, product releases, literature offerings, letters and, of course, a slate of tutorial and case-history articles. To be considered for publication, articles should be submitted by Jan. 7, 2000. Products/news/literature, etc., should be submitted by March 1, 2000. All submissions and inquiries should be made to:
Acknowledgment Mark Peters is publisher, Laura Kane is copy editor and Henry Terrell is Production Director of Fieldbus Technology. We thank Fieldbus Foundation and Profibus International for their cooperation, and Owens & Campbell, Inc. for coordinating with Fieldbus Foundation.
Copyright © 1999 World
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