An aging fieldbus system was causing too much aggravation for engineers and technicians at Radiator Specialty Co.’s Charlotte, N.C., factory. A palletizing system for containers of Gunk, Liquid Wrench and other products was often stopped when a fault on one node brought the whole system down.

Networking glitches became so common that technicians created a workaround so that many of the workers on the plant floor could restart the network.“We put a power switch on the system so equipment operators could reboot when we weren’t around,” says Shawn LaHart, control technician at Radiator Specialty. That reduced the pain and saved time, but production still remained at a halt for a couple of minutes while the system rebooted.

Late last year, the company installed an Ethernet-compatible field bus, bringing the office networking standard used in the factory down to the input/output (I/O) level. Now that Radiator Speciality has deployed Beckhoff Automation’s EtherCat protocol, the emergency power switch is getting dusty.“Our EtherCat system’s been running for months without any errors,” says Project Engineer Murray Williamson.

Radiator Specialty is one of many manufacturing companies taking Ethernet down to the fieldbus level, making the ubiquitous network look like the winner of the fieldbus wars of the mid- 1990s. It’s even being used to tackle real-time problems, as many vendors provide variations that provide determinism.

Analysts note that adoption is still low compared to the fieldbuses that have been used for years.“There are still more nodes of all other fieldbuses than of Ethernet, but it’s definitely growing pretty rapidly,” says Harry Forbes, senior analyst at ARC Advisory Group Inc., in Dedham, Mass. He notes that in 2004, there were fewer than 1 million Ethernet nodes at the fieldbus level.

However, there are a number of reasons that Ethernet’s growth in this role is expanding. Among them is that once standard Ethernet cabling—called “Cat 5” in the industry—is installed, companies are no longer tied to a fieldbus. Ethernet gives manufacturers an open environment, letting them use hardware and software from various vendors. For many engineers, that’s cause for celebration.

“Ethernet as a fieldbus has a ton of advantages,” says Ryan Becker, senior programmer analyst at Brown Printing Co., which prints many national magazines at its Waseca, Minn., headquarters. Brown is now using modules from Opto 22, of Temecula, Calif., to connect to I/O points.

Becker notes that with older fieldbuses, it is difficult to extract data for production reporting, and it’s expensive to use their specific middleware to tie into I/O points. Now, he uses Java, C or Visual Basic programming languages to access nodes. “With Ethernet I/O, I can communicate directly to I/O points at no added cost, and I can use any language I choose to tie into I/O points and extract data,” he adds.

Vendors note that the broad support for Ethernet makes it much simpler to do many common jobs. Ethernet connections and compatible software are on personal computers (PCs), and there are a number of off-the-shelf programs for many common tasks.“Now it’s relatively easy to develop and monitor software.

Every laptop has Ethernet, so you can use a Web browser as a debugging tool.There’s nothing else to buy,” says Helge Hornis, intelligent systems manager at Pepperl+Fuchs, a network component supplier based in Twinsburg, Ohio.

Another benefit is that regardless of which communication protocols are deployed, data can be transferred freely throughout the network. That means maintaining these systems can be handled efficiently even from remote locations. “Now I can monitor the whole system from my desk, I don’t have to go onto the floor and plug into a system,” says Williamson, of Radiator Speciality. He adds that he can also log in from home or from an off-site meeting.

Finding people who can do this debugging and other work is also much simpler.“The knowledge base for Ethernet is far higher than for any fieldbus,” says Benson Hougland, marketing vice president at Opto 22. This experience makes it possible to set up a fieldbus in fairly short time.The PC world’s push towards plug-and-play has made a networking technician’s job relatively simple.

“Reconfiguring the system was mostly copying and pasting. I had the whole thing done in a day,” says Radiator Speciality’s LaHart.That installation has eliminated delays from oft-occurring shutdowns, which provides a payoff that Radiator Specialty management understands and appreciates. “An hour to us is a few thousand dollars, so we’re probably looking at a few tens of thousands of dollars in extra throughput,”Williamson says.

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