of the main reasons for making this change.

“Using Profinet and Profibus separates industrial automation from IT (information technology), so there’s no confusion about what part IT is involved in and where industrial people take charge,” Zarreii says. Having Ethernet in industrial environments meant IT staffers had to help troubleshoot when problems arose. The IT specialists don’t understand the plant floor requirements, so it’s very time consuming to get them to devise fixes that meet those requirements, Zareii adds.

The newest Dekalb County facility will have Profibus in most areas, with a minimal amount of Profinet. Product availability is a key reason behind that decision. The PTO’s Henning says that’s a big factor in the continued growth of Profibus. “There are thousands of Profibus offerings, compared to hundreds for Profinet,” Henning notes. That is driving growth that many didn’t expect once Profinet started gaining momentum. “We continue to see Profibus growing like mad, 25 percent per year or so,” Henning says.

Though Dekalb County uses DeviceNet and Profibus, they aren’t the only architectures in its facilities. Today, those plants have many small components that are connected using complex analog wiring schemes. In newer networks, those components are being linked with a low-level networking architecture.

“No matter what you do, you’re still going to have a lot of little things that give you a lot of analog parts. We’re using the AS-Interface, which lets us go from 16 wires to two. That saves us copper wiring and conduit,” Zarreii says.

Broad expanse

The continued growth of fieldbus architectures is prompting changes in many segments of the broad electronics industry. Equipment makers aren’t the only ones who are racing to provide new features and functions for the various fieldbus architectures. Chipmakers are also making sure their microcontrollers help these suppliers get to market quickly. “We support any fieldbus anyone asks about,” says Alexandra Dopplinger, global industrial leader for factory automation at Freescale Semiconductor, a chipmaker in Austin, Texas. “We provide the interfaces.”

When engineers are linking fieldbuses to Ethernet, that means microcontrollers must have at least two Ethernet ports and more than eight UARTs (universal asynchronous receiver/transmitters), Dopplinger explained.

Yet another sign of ongoing growth for fieldbuses is that new consortia continue to address issues relevant to their use. In September, Cisco, Sun Microsystems, and chipmakers Atmel, Freescale and Jennic joined a number of others to establish the Internet Protocol for Smart Objects Alliance.

IPSO’s goal is to promote the use of Internet Protocols for sensors and other embedded devices. The group notes that IP can be used on a range of wireless and wired networks. Wireless communication is a growing area in industrial applications, with a number of different proprietary and open protocols competing for what’s expected to be a huge market.

That market may grow more rapidly if a repeat of the fieldbus wars is avoided. “Sensor arrays are moving to wireless. Companies also need to use technologies like IP. The alliance will develop code that will help promote the use of IP in these applications,” Dopplinger says.

While managers debate the pros and cons of various networking schemes and protocols, those issues will fade once the installations are up and running. Then, users will be trying to get the most out of the networks. Though that end goal can be overlooked, it’s always important to keep it in mind.

“The real advantage is not which bus technology people use, but the information they get,” Siemens’ Shaikh says. “You have access to all sorts of information in intelligent devices. You can also check the performance of devices and maintain them using this information.”

Sidebar - Bridging the Gap
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