It looks like the Profibus Trade Organization ( PTO, www.us.profibus.com ) will be putting more emphasis on promoting Profinet in the coming months. In the past, the trade group—which is the North American arm of Profibus International—worked to balance its push of both Profibus and Profinet. But PTO members attending the group’s annual General Assembly Meeting in Scottsdale, Ariz., Aug. 5-7 made it clear that they want the organization’s leaders to concentrate on promoting Profinet—the open Ethernet version of the Profi family of networks.This is a switch from past years, when members expected the PTO to promote Profibus and Profinet equally.

The subject prompted a lively discussion among attendees. Mike Bryant, the PTO’s executive director was quick to embrace the challenge, while noting that this was a sea change for the trade group. The change in view among members was clearly based on the recognition that Profibus has become well established in the vendor community and installed base. With that accomplished, members are now asking the PTO to emphasize Profinet.

By the numbers

Bryant certainly had the numbers to show Profibus’ wide industry acceptance. According to PTO calculations, the number of installed Profibus and Profinet nodes has grown considerably in the past year. Profibus now claims a 47 percent share of installed fieldbus nodes. Next in line is Interbus with 22 percent of installed nodes and DeviceNet with 10 percent. CCLink, Foundation Fieldbus, Modbus TCP and EtherNet/IP all showed up in single-digit percentages. The installed base of Profinet is 2 percent.

The PTO pointed a major milestone this year with 25 million Profibus DP (decentralized peripherals) nodes installed. Back in 2004, PTO leaders predicted there would be 20 million installed nodes by 2008, so the group exceeded its target. Bryant predicts another doubling over the next four years, expecting the total to hit 50 million nodes by 2012. The Profisafe installed base has also been growing, averaging roughly 70 percent per year as it pushes toward the 500,000-node mark.

Bryant noted that Profinet has been following the steep growth curve of Profibus. There are now more than 1 million Profinet nodes installed. The PTO expects Profinet nodes to exceed 3 million by 2010, an average annual increase of 37 percent. The rise of installed Profibus and Profinet nodes has been exceeding the general growth in industrial Ethernet devices. Bryant cited a report from the ARC Advisory Group Inc., Dedham, Mass., that predicts an average 27.5 percent growth in the market for Ethernet-capable devices and I/Os over the coming five years.

Working together

Bryant was quick to point out that Profinet was not developed as a replacement for Profibus. He emphasized how the two technologies work together. “One of the major selling points of Profinet and Profibus is that they play well together,” says Bryant. “This means that you can use a Profibus device now where no Profinet device is available with the assurance that it will fit in a Profinet system.”

He noted that many systems use both Profibus and Profinet technology. “You can choose Profinet because you need its larger address space, greater bandwidth, enterprise connectivity and peer-to-peer integration capability and know that you can still use Profibus devices in the system,” says Bryant. “As more Profinet devices become available, you can transition more and more devices to the Profinet network without having to go through a large learning curve. This positioning is bolstered by the commonality—existing and planned – of the application profiles.”

Bryant also explained that Profinet’s modularity means users don’t have to do everything at once. New applications can be added to an existing system. “Profinet is modular—you use just the part you need,” said Bryant. “So we emphasize to users, ‘Choose a bus that will do what you need to do now and what you may need to do in the future, such as motion and safety.’” He noted that modularity is an important concept to ease the fear that something as all-encompassing as Profinet must be complicated.

Looking ahead

Bryant made some predictions about the future of Profibus and Profinet. “Profibus will continue to be the most successful fieldbus technology,” says Bryant. “Over 30 million Profibus nodes will be installed worldwide by 2011.” He also noted that the growth curve of Profibus will slowly flatten and afterwards will go down. “This trend will probably begin earlier in Europe – perhaps in 2009 – than in the Americas and Asia.”

He believes a shakeout is coming for industrial Ethernet solutions, probably within the next five ...