Profibus Group Outlines Roadmap

Marking its 10th anniversary, the U.S.-based Profibus Trade Organization (PTO), with its parent, Profibus International, has launched an initiative to promote Profibus as “the world’s number one fieldbus,” and a market leader across factory and process automation segments.

Edgar Küster, chairman of Profibus International, in Karlsruhe, Germany, cites the sale of 10 million Profibus application-specific integrated circuits (ASICs) as the benchmark basis. According to the trade group, Profibus achieved 20 percent growth worldwide in 2003, and is projected to double its market in the next four years to 20 million nodes. Says Küster, “The Profibus device suppliers have made the technology investment. It’s now time to pick the low-hanging fruit.”

Of the current base, Mike Bryant, executive director of the PTO, estimates about 10 percent of that, or one million nodes, are installed in the United States. Says Bryant, “We’ve had big segment growth in the U.S. and China,” due mainly to Profibus’ strengths in factory automation, safety applications, drives and motion control, and hybrid process automation, such as food and beverage, pharmaceuticals and water/wastewater treatment—“applications that use programmable logic controllers, not distributed control systems.”

Ethernet Everywhere

As Ethernet plays an increasingly important role in automation systems, migration challenges for Profibus include protecting users’ and suppliers’ existing investments, while bringing real-time functionality to the Ethernet protocol. Profinet, an industrial Ethernet application, provides 100 millisec response for standard communication and uses soft real time (SRT) enhancements for 10 millisec response, suitable for most factory automation applications.

For high-performance applications, such as motion control, which require 250 microsec to 1 millisec response times, Profibus International has developed a real-time switch ASIC for isochronous real time (IRT) data transfer with jitter of less than 1 microsec.

The performance matrix for the real-time switch ASICs, called the Ertec 200 and Ertec 400, allows for up to 150 control nodes at a cycle time of 1 millisec, with 6 MB/sec of simultaneously transferable TCP/IP data. The ASIC switches will be available in late 2004, while drives and controllers with the ASICs will be available during the second and third quarters, 2005. Profinet is part of the existing IEC 61158/61784 specification, and is liaising with IEC SC65C NP for real-time Ethernet using the SRT and IRT solutions.

Profinet integrates with other fieldbus solutions through proxies. Recently, Profibus International formed a working group to facilitate the integration of Interbus fieldbus technology with Profinet by developing a proxy specification by September 2004. Citing 6.5 million Interbus nodes installed worldwide, Profibus International says the combination of Profibus and Interbus market shares will help to promote Profinet as the leading industrial Ethernet solution.