Crown Energy Technologies, of Calgary, Alberta, Canada, needed to create a network to connect all of its oil equipment out in the field. The company’s electrical manager, Ging Kee Lem, viewed the collective oil field equipment as a process plant, albeit, a very scattered one. Lem brought in Calgary-based Advanced Measurements Inc. as the integrator, and Austin, Texas-based National Instruments Corp. as the device provider. Together the three companies created an Ethernet network to centrally connect the dispersed oil field equipment.
Given that individual pieces of equipment used different controls, a bus-based proprietary network was out of the question. Instead, the players chose Ethernet to blend the different controls into an open-standard whole. “Our processes are all mobile. Just imagine a process plant that is broken into small pieces and distributed in the oil fields,” says Lem. “We have many different control systems on that equipment. We’re trying to build a command network that will connect all the different control devices.”
There were a number of reasons for choosing Ethernet for the network. “There were four benefits for standardizing on Ethernet for our controllers,” explains Todd Walter, the industrial automation and control product manager at National Instruments. “For one, the prices have come down, and secondly, it’s much easier to get machine-to-machine communications with Ethernet.” He also notes that it’s easier to swap parts when the network is Ethernet. The other benefits involve the communication network itself. “With Ethernet, you can share different types of communication over one cable, and it has more bandwidth,” says Walter. “You can send much more data over the cable.”
The cost savings of Ethernet also showed up as the team sorted through potential hardware for the network. “With Ethernet, there is a variety of hardware we can use,” says Lem. “Using a wide variety of hardware allowed us to more easily control costs.” He notes that with bus-specific networks, the customer has to use manufacturer-specific hardware, so there’s not room to shop price.
The final reason for choosing Ethernet is that it has become more reliable in difficult environments and it’s more widely adopted than it was a few years ago. “As an integrator, we didn’t use a lot of Ethernet five years ago,” says Steve Conquergood, chairman and founder of Advanced Measurements. “In the last couple of years, we’ve seen Ethernet become the absolute stadard. With Ethernet, we can choose ten different pieces of hardware.” He notes that now he only uses non-Ethernet networking when a customer specifically demands it.
Conquergood notes that Ethernet is also easier on the user. “Ethernet has a high bandwidth, which lets many people simultaneously view operations,” says Conquergood. “You may have a diagnostic technician who just needs to see a particular view of what’s happening on the network.” The maintenance team can view just a portion or the entire network without interfering with operations. That allows maintenance to create a constant view of plant equipment, since that view does not compete with plant operators for bandwidth. The constant monitoring allows maintenance to see potential part failures before they happen.
Low cost edge
The biggest reason Ethernet adoption has accelerated over the past two or three years is its relatively low cost. Ethernet is not only less expensive than proprietary automation networks, but its multiplex nature requires less cabling, which is another money saver. As an added cost bonus, Ethernet easily integrates wireless technology, thus allowing engineers to build a network that includes both direct cable connectivity and wireless signals.
For many users, the ability to connect to multiple devices on one cable is enough to tip the network decision to Ethernet. “The biggest reason for customers to migrate into Ethernet industrial networks is cost reduction,” says Francisco Tacoa, North American product manager for Weidmuller Advanced Connectivity Solutions, at The Weidmuller Group, in Richmond, Va. “With Ethernet, you take advantage of multiplex technology and do away with a lot of cabling. In automation systems, 50 percent of the cost is in cabling and enabling the connectivity—not in the machines.”
Ethernet’s wide acceptance in recent years encourages even wider adoption. “In the industrial environment, Ethernet has become mainstream in the last three to four years,” says Patric Dove, application engineer at Advanced Automation, in Taiwan. “That’s because it has become familiar to people, it’s inexpensive, and it’s easy to implement.” Dove gives credit to hardware vendors who have worked to make Ethernet easy to use. “Ethernet has become mainstream through the wide availability of hardware switches and hubs. Hardware companies have put in hard work to develop Ethernet protocols.”
Another cost savings comes through the ease of converting a plant network to Ethernet. “You don’t have to reorganize your factory to use Ethernet,” says Tom Edwards, senior technical advisor at Opto 22, a Temecula, Calif., automation systems provider. “You don’t have to rewire your network. You just unplug the devices and plug them back in and you can use Ethernet.” He also notes it’s easy to keep the factory network separate from the business network with Ethernet. “You can segment Ethernet so the industrial network does not interfere with the business network.”
Upgrade with ethernet
With corporate mergers and the subsequent need to integrate a number of differing legacy automation systems, those running automation systems put a high value on a network that can incorporate a variety of hardware. Some plants continue to use proprietary systems simply because that’s the legacy system they have. As they upgrade the network, however, many plant operators are turning to Ethernet. “If your entire plant is on Profibus and you need to talk to hardware, it makes sense to continue with Profibus,” says Dove, of Advantech Automation. “But if you have a new line that doesn’t speak to Profibus, Ethernet is the answer.”
Dove notes that Ethernet can speak to any of the existing bus technologies. “Ethernet can be used to communicate with proprietary protocols. You can go Interbus-to-Ethernet, or Profibus-to-Ethernet. You can bridge Ethernet to any of the proprietary protocols.” He notes that some manufacturers use Ethernet as a data gateway to convert from one proprietary protocol to another. Though this works, Dove doesn’t think using Ethernet as just a conversion tool is the best use of Ethernet’s potential. “I’ve seen manufacturers use Ethernet to talk to existing hardware that’s on a proprietary network, but it’s not a common practice because it slows down the hardware.” He sees Ethernet as much more effective when it is the core network.
security concerns
The upside of an open standard network such as Ethernet is its ease of use. That’s also its downside. If it’s easy for your operators to use, it’s also easy to crack for those who are not supposed to access the system. “Security has required a learning curve for the industry. The whole methodology of process networks is that it’s simple to use and the operator has access to all of the information,” says Tom White, senior network engineer at Honeywell Automation and Control Solutions, in Minneapolis.
Plant operators like the benefits of an open network, so they tend to approach security carefully. “There is a give and take relationship between openness and security,” says White. “It becomes a risk management question. You have to assess the advantages of open access against your security vulnerability. If we allow access to this network, do we open ourselves up to a possible threat? Is that risk acceptable or do we need to do something to mitigate that risk?
“People are starting to create networks with security in mind. Security used to be an afterthought, with availability being the higher concern.” White notes that before security became a concern on the plant level, networks were designed to run all of the time and be open to everybody. “Now we’re seeing a greater concern about cyber security as attacks come through the IT (Information Technology) world through malware, worms and viruses.” He notes that those problems often enter the network when an employee brings along some music from home and loads it on the PC at work.
Many believe that security is a manageable concern, given the many benefits of an open network. Given its many plusses, it’s not surprising that Ethernet has taken hold as the preferred plant networking protocol in the last couple of years. While cost is the primary driver, the cost savings comes in a number of ways. Because it can accommodate legacy systems, Ethernet can be used as the vanilla protocol to integrate differing hardware. It easily accommodates wireless, and it can manage a wide flow of data on existing cables. The downside is its very openness. When using Ethernet, plant operators will have to ward against security breaches.
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See sidebar to this article: WIRELESS BOLSTERS ETHERNET
