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.”
Mike Bryant, executive director of the PTO, estimates about 10 percent of the current base, 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.”
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 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.
Jane Gerold
