Equipment operators at three Ridgeview Industries factories dutifully entered their production numbers at the end of every shift, a task that took 10 to 15 minutes. Although there were 50 to 60 personal computers (PCs) scattered through the automated assembly plants, employees sometimes had to wait while coworkers finished keying their data in.
This information gave managers an average of what had been produced, but they couldn’t see data in real time, nor could managers tell how long a machine was used during a shift. Management wanted more immediate data, and a way to share this up-to-the-second data more freely.The solution came from a technology that’s gained worldwide acceptance as a readily accessible pathway for instantaneous communication.
“The need for more precise data drove us to Ethernet and TCP/IP (transmission control protocol/Internet protocol).That made it possible to display data in a standard format that anyone could see from anywhere and quickly understand what was going on," says Terry Krueger, senior control engineer at Ridgeview, a Grand Rapids, Mich., company that does robotic welding and stamping for the automotive and furniture industries.
Collecting data directly from the equipment didn't just free operators from the tedious data entry and provide managers with real time information on every machine's output, it also opened up more space in the plants. "Most of the PCs on the floor disappeared," Krueger says.
Ridgeview is one of a growing number of companies that are adopting Internet protocols to gather and share data from factory floor equipment. The move to TCP/IP, eXtensible Markup Language (XML) and other Internet protocols has been facilitated by the acceptance of Ethernet in the manufacturing environment. This push to standardized communications also makes it easier for executives, financial managers and others to share data throughout the enterprise.
The transition to Internet protocols began a few years ago in the industrial field, but it’s still moving from early adopters to a more widespread presence.“It’s not commonplace, but it’s no longer cutting edge. Clearly, all the automation suppliers are moving that way, so I have no doubt it’s going to become dominant,” says Mark Knebusch, a director at Harbor Research, in Boston.
That sentiment is shared in many fields, including robotics. “We’ve used XML for a couple of years. My hope is that it will become a de facto standard. It’s adaptable, so one version can talk to another,” says Greg Webb, PC software manager at Motoman Inc., a robot vendor based in West Carrollton, Ohio.
Internet protocols have become popular enough that they’re being included in many new products. Users who want to stay up to date now have added incentive to make the transition if they haven’t already.“If you want the latest, most powerful software to do the fanciest control tricks, you’ve got to be on Ethernet,” says David Crump, a spokesman for Opto 22, a Temecula, Calif. based automation supplier.
That’s becoming simpler as time passes.Though Ethernet and Web-related technologies are making significant inroads, most applications today remain customized upgrades, handled in various facilities. But a growing number of products are integrating TCP/IP and other Web-related schemes. “The key to acceptance will be when modules start showing up in equipment, so companies don’t have to add it on,” Crump adds.
Though all technologies advance more quickly once they’re embedded into hardware, Krueger notes that it’s no longer a major undertaking to deploy modules that don’t have Ethernet and TCP/IP built in.“If we get a new piece of equipment without a converter, doing something like going from RS-232 to Ethernet only takes eight or nine minutes to set up.The protocol is very simple to implement, the biggest challenge is finding ways to display data,” he says.
Those modules are becoming more common. For example, Irvine, Calif.-based Triconex recently came out with a communications module that links its Safety Instrumented Systems and Distributed Control Systems without compromising either safety or security. It incorporates an Embedded OPC Server (OPC is an open communications protocol) and Modbus TCP/IP, supporting full TCP/IP and routing functions to communicate over either local or wide area networks.
As the technology matures, clever design engineers are figuring out how to use these protocols to do more with less.That’s true in both products and standards. In the standards environment, motion control has recently been added to the Profinet fieldbus architecture, letting equipment designers use Profinet to set up and control up to 150 axes of motion with latencies of less than 5 milliseconds.
“The magic is that TCP/IP and motion control can exist on the same wire.You don’t need separate buses for motion control and Ethernet,” says Carl Henning, marketing director for the Profinet Trade Organization, headquartered in Scottsdale,Ariz.
On the product side,TCP/IP and other iterations are seeing extended use. As new technologies such as wireless communications come to the fore, they are incorporating Internet protocols as a matter of course.
“We’re seeing more and more requests for sensors to use Internet protocols as sensors move to low bandwidth wireless links like ZigBee,” says Mark Prowten, senior product marketing manager at Lantronix, an Irvine, Calif.-based network products provider.
Many suppliers of ZigBee, a wireless networking specification, believe that ZigBee will be used to link sensors and other technologies together, particularly in applications in which battery powered products can easily be installed without wires.
The benefits of using TCP/IP and Ethernet include simplified communications with front office systems, which have used Internet protocols for years. “There are real benefits to gathering data in a standard way. Most manufacturers realize that there are real advantages to tying the floor automation backbone to the corporate backbone,” Prowten says.
Upper management likes the added visibility, and engineers like the extra sleep that Internet access provides.“We can communicate from anywhere, even doing troubleshooting from home. That has saved me 40-minute drives to the plant when there’s a problem, which is really nice when the problem occurs at 3 a.m. I can just log in, see what’s going on, and tell someone which switch to push,” Krueger says.
While it’s now simpler to log in from any location, it’s also becoming much simpler to communicate with other manufacturing operations located in remote buildings. Most of the older networks used for factory automation were designed for fairly short distances. But Ethernet makes it possible to communicate between buildings located on a campus.“There’s a huge advantage to being able to leverage the bandwidth of Ethernet. It can be tied via wide area network to other facilities,” Prowten says.
While there are many benefits to the shift, many vendors believe that existing networking schemes and protocols will hang around for a long time. Existing equipment that works well won’t be removed.Those who want to extend equipment lifetimes can perform translations from other technologies to Internet protocols.
“A lot of customers have spent tens of thousands or even hundreds of thousands of dollars on proprietary systems. They don’t want to change everything, but they still want to tie that equipment to the corporate backbone,” Prowten says.
“Once this equipment gets speced in, it’s in for a long time, but it still needs to communicate,” says Joel Young, engineering vice president, at Digi International, a Minnetonka, Minn.-based supplier of device networking products. “The fieldbuses will be around for a while. If they’re happily moving along, they probably won’t be changed,” says Young.
Some vendors feel that any justification for fieldbuses will fade as products begin adopting IEEE 1588, an Institute of Electrical and Electronics Engineers standard that was completed earlier this year.“It makes Ethernet look like a fieldbus.As IEEE 1588 comes along, fieldbuses will whither away,” Young continues.
The standard provides known latency times, putting time stamps on messages so that delivery times can be determined precisely, he explains. That will eliminate problems that can occur with current versions of Internet technologies. “Because of the way TCP/IP is set up, retransmitting on error messages, you can see latencies that cause problems in critical applications,” Young observes.
However, the transition to 1588 will take several years, if indeed it happens. Until then,many users will want to stick with technology they’ve grown familiar with, sticking to the “if it ain’t broke, don’t fix it” adage.
“A lot of companies have [specified] protocols and bought technology embedded in PLCs (programmable logic controllers), motor drivers and other products. They want to use proprietary protocols on the device side and still be able to take data out to their networks on the other side,” Prowten says.
While Internet protocols are making big inroads into the factory, the Internet itself isn’t seeing similar success. Companies that have remote sites around the country or internationally rarely turn to the Web to communicate at the production level.
Instead, they typically rely on intranets, since they have more control over the delivery of critical data used on the plant floor. In these days of viruses and denial of service attacks, the Internet is not the most trustworthy place. “Most people don’t use the Internet. An automaker doesn’t want a production line to go down because of problems on the Internet,” Prowten says.
One of the few potential issues for Internet protocols is at the next step upward in the software hierarchy.“We had the fieldbus wars five or 10 years ago. Now the battle is at the application layer.You’ll continue to have situations where plants will have multiple control protocols running on top of TCP/IP, but most often in separate subsystems,” predicts Harbor’s Knebusch.
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