Ethernet continues its march onto the factory floor. Using standard, open Ethernet in conjunction with traditional low-level field networks, such as DeviceNet, Profibus and Fieldbus, can reduce hardware costs and ease administration. More importantly, connecting the two worlds allows executives to monitor shop floor activities and quickly adjust their strategies.
"Ethernet gives you the potential for global information visibility," says Harry Forbes, senior analyst, automation, for ARC Advisory Group (Dedham, MA). Executives can examine plant and equipment performance and make decisions that optimize profitability. But it's not just a matter of linking proprietary control networks with Ethernet-based information networks. "All of the automation vendors are developing technologies that can be used to make Ethernet the primary network for machines and motion," says Forbes.
Manufacturers are looking for one network to do it all throughout the factory. "They want one network for process, batch, discrete, motion control, drive control, supervisory control, robotics and safety. And, oh yeah, they want that same network to go from the factory floor to the business systems," says Brian Oulton, marketing manager for Logix, Net Logix and Kinetix for Rockwell Automation (Milwaukee).
ETHERNET IS THE ANSWER
Ethernet is a natural fit for these diverse demands, he adds. There are already over two billion users of standard Ethernet TCP/IP worldwide. Manufacturers that leverage standard Ethernet can take advantage of rapid developments in the commercial marketplace. Rockwell is a proponent of EtherNet/IP, which extends commercial-off-the-shelf (COTS) Ethernet to the Common Industrial Protocol (CIP) and is sponsored by the Open Device Vendors Association (ODVA).
According to the ODVA, the first commercial implementations of EtherNet IP appeared in 2001. There are now more than 50 vendors shipping products based on EtherNet/IP. Rockwell Automation has sold 500,000 EtherNet/IP nodes, according to Oulton. In 2003, Cisco Systems Inc. (San Jose, CA) announced its Cisco Catalyst 2955 Series, a rugged switch designed for use in factory floor environments. This breakthrough product enables Fast Ethernet or Gigabit Ethernet connectivity automation networks and information networks.
WARY BUYERS
As with other major developments, buyers have been somewhat slow to react. "These technologies have not been absorbed by the market yet. It takes a while for manufacturers to move," says Forbes.
But momentum is picking up. According to an April report from ARC, 840,000 industrial Ethernet units were shipped last year, and unit shipments will grow to 6.7 million in 2009. Worldwide revenues from industrial Ethernet switches (including the Cisco Catalyst 2955) hit $124 million in 2004 and are expected to grow to nearly $940 million by 2009. Sales of industrial Ethernet switches will see compound annual growth from 2004 to 2009 of nearly 50%, according to ARC. "We think industrial Ethernet is going to continue to grow for the foreseeable future," says Forbes.
LET'S GET DOWN TO BUSINESS
But with the initial hype subsiding, it's time to get serious. There is now a real push to link factory floor control networks to office information networks using standard Ethernet. The doubts have all but faded away, and the naysayers are growing silent: Ethernet is robust enough, fast enough, reliable enough and secure enough to work on the factory floor. "The automation side of the house sees the benefit of an open standard as well as the benefit of sharing the data upstream," says Mark Wylie, solution manager, manufacturing vertical, at Cisco Systems (Milwaukee). "They're not doubting that Ethernet is robust and real time, but they want to know how to implement it in an informed fashion."
ETHERNET ADVANTAGES
Ethernet also has a scalability advantage. "EtherNet/IP can handle very large applications where most fieldbus networks can only do 30 nodes. The largest EtherNet/IP application has 120 drops of I/O, eight to 10 controllers and lots of HMI. Standard Ethernet can support networks that big," says Oulton.
Ethernet can be made safe enough for industrial applications. Sick AG (Waldkirch, Germany), in conjunction with Rockwell and Omron Corp. (Kyoto, Japan), has been working on "Safe Ethernet," a safety communications protocol. The standards organization TUV has certified Sick's Safe Ethernet version to be used without hard wiring. Customers can add safety functionality to existing networks -- whether Ethernet, DeviceNet, Profibus or another common protocol -- without the need to swap out existing applications and equipment. "Our technology allows people to easily integrate safety into their network," says Steve Freedman, director of safety systems for Sick USA (Minneapolis).
Ethernet has also given OEMs the ability to modularize their automation components, says Forbes. Using products based on modular Ethernet components would allow companies to avoid customization, for the most part, managing lots of modularized PLCs (that can be easily swapped out or changed) rather than a few highly-customized ones.
MODULARIZED AUTOMATION
According to Forbes, the Siemens AG Logistics & Assembly Group (Nuremberg, Germany) was the first OEM to work on a commercial application of modularized automation based on Ethernet, demonstrating a test site at a brewery last year where the conveyor system was made up of hundreds of modular PLCs rather than eight to 10 highly-customized PLCs. In addition to avoiding customization, "You can distribute changes much more easily. It's a much more sophisticated way of managing the automation software and hardware," says Forbes.
Modularization also gives better control. Rather than having to figure out every possible impact to customized PLCs, users can reconfigure a modularized line much more quickly. Modularized Ethernet is not yet ready for prime time, since Siemens has only recently had demos of the technology. But Forbes believes other automation vendors will follow in short order. "This is the direction that the large automation OEMs will go in," he says.
One of the biggest developments in industrial Ethernet is the mix of COTS technology with industrial technology within the same product. For example, the Rockwell Automation ControlLogix product line includes a module called eWeb in its chassis. As its name implies, eWeb serves Web pages and handles e-mail. The eWeb capability became available this year.
WORKING TOGETHER
Implementing Ethernet on the factory floor requires a high degree of collaboration between the automation side of the house and the IT staff. Traditionally, this was a stumbling block as each had its own practices, vocabulary and goals -- and little understanding of the challenges faced by the other side. Now, the stakes are so high it is clear that IT must learn from the factory side and vice versa. "The battles are not over, but both sides know they have to reconcile," says Paul Steinitz, director of marketing for Foxboro Automation, a unit of Invensys Process Systems (Foxborough, MA).
FOCUSING ON SECURITY CONCERNS
Network security is the nexus of concern for both automation and IT. "Industrial Ethernet security is not the same as IT security. Imagine taking your manufacturing process offline while you download a new patch. There are a lot more considerations in implementing security for industrial Ethernet," says Wylie.
Ironically, in the last year or so Wylie has seen factory automation professionals accept the notion that Ethernet can be made secure enough for a control network while their peers in IT get progressively nervous. "Many more IT folks are seeing the danger of taking responsibility for the control network. They're more apprehensive than we thought they would be," says Wylie.
That is not surprising, says Steinitz. "Field networks are very far from what IT knows about." With the prize of using robust industrial Ethernet throughout the plant and enterprise, collaboration between IT and automation will continue.
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