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Fieldbus Wars continue

ControlGlobal.com

As wireless Ethernet continues its aggressive growth, end users have to wonder, “Will it replace fieldbuses?” Senior Tech Editor Rich Merritt investigates the situation and finds that clearly a battle is shaping up.

LAST MONTH, at Hannover Fair in Germany, the press releases were flying: Profibus claimed to have 15.4 million nodes installed worldwide, with 530,000 in process systems. ODVA announced its 1 millionth EtherNet/IP node had been shipped. (Way back in 2003, Rockwell Automation announced that that it alone had shipped more than 1 million DeviceNet nodes.) Foundation fieldbus appears to be leading in process control applications, claiming 625,000 devices and 10,000 systems installed. Though some don’t call it a fieldbus, ARC Advisory Group estimates that some 10 million HART-enabled devices are in the field.

Complicating the matter is wireless. At Hannover Fair, 40 companies exhibited wireless automation devices. Clearly, a battle is shaping up. The next Fieldbus War, perhaps. And some end users are getting tired of it.

Can’t They Play Nice?
“I would put the fieldbus wars in the same vein as left-handed versus right-handed driving, English versus metric measurements, letter size versus A4 size, Beta versus VHS format and other contests,” says Eric Marcelo, senior instrument specialist at Nestle Phils, Cagayan de Oro Factory, in the Philippines. “A group of people came up with the fieldbus concept and developed it. Another group thought they could do better or maybe were unwilling to lose their own technology if they adopted the other group's system. Maybe it's just plain old human pride but the result is the same—chaos. “Instead of banding together, and coming up with a universal standard, developers continue to push their systems, hoping for the trigger that will one day eliminate all other contenders. In the meantime, we end users are caught in the crossfire.”

Patrick Rossi, process automation project manager at Mead Johnson in Evansville, Ind., adds, “The splintered state of fieldbus has left end users unable to decide which buses to embrace. With no clear choice to inexpensively deploy to address analog and discrete instrumentation and motors, our choice is not to choose. We'll just wait for the next ‘breakthrough’ technology to emerge to reduce initial and residual costs.”

Ken Smothers, I&C maintenance supervisor at Aquila Lake Road Station, puts it simply: “We considered it for one project, but we rejected it based on the known complications and the plant's lack of confidence in the technology.”

Ed, a refinery engineer, who must remain anonymous, adds, “Vendors generally don't like to play nice together. We recently installed 300 Foundation fieldbus instruments on a new refining unit in the U.S. We had plenty of problems getting devices to talk to our system. It did eventually happen, but getting the right device descriptor files wasn't easy.”

Still, Ed says he’s happy with fieldbus. “The installation is very clean. I've enjoyed some of the diagnostic capabilities and the ability to interact with the instruments from the control system. Being able to get the actual valve position back from the positioner solves a major control engineer headache—knowing whether or not the valve is working, and more importantly being able to get it fixed.”

On the other hand, some fieldbus users have no complaints. Air Products’ plant in Wichita, Kan., recently installed a Simatics PCS 7 control system with Profibus. “We’re pleased with the improvements and cost reductions from the Profibus installation,” says Dean Kerr, senior engineer at Air Products. “The project was completed on schedule and below budget. Profibus gives us the broadest choice of field devices from a large pool of name-brand suppliers. We can seamlessly integrate all of them on our network.”

Fieldbus Here to Stay
“I agree that the current state of fieldbus is in a tremendous state of flux, with technology moving way faster than customer acceptance,” says Arnold Offner, national/international committee manager for Phoenix Contact. “In North America, most of the latest fieldbus process installations have been upgrades to existing plants, with a resulting improvement in efficiencies. However, all the new fieldbus projects are in other parts of the world.”

	FIGURE 1: OIL AND GAS INDUSTRY PUSHES FIELDBUS
	The oil and gas industry was one of the first to embrace fieldbus technologies, and continues to be one of the primary fieldbus users. Brunei Shell Petroleum Co. installed Foundation fieldbus technology on this unmanned offshore platform. Source: Emerson Process Management

Kristen Barbour, product manager at Pepperl+Fuchs, says the oil and gas industry (See Figure 1) is a big driver. “Today almost all greenfield installations in the oil and gas industry are using Foundation fieldbus,” says Barbour. “Because the industry’s users were early proponents of Foundation fieldbus, they were early testers of the technology, and are very committed to it, not only for the installation savings, but also for the long-term cost savings that fieldbus provides.”