Connectivity is like motherhood: Everybody praises it in the abstract; it’s the concrete examples that can spark disagreements. One thing that there is little disagreement about, though, is the central role of Ethernet.

“Ethernet is the foundation for establishing heightened communications,” says Robert Muehlfellner, director automation technology, at vendor B&R Industrial Automation Corp., Roswell, Ga.

Mike Hannah, business manager for NetLinx at Milwaukee-based supplier Rockwell Automation Inc., concurs, seeing the technology as a natural fit for the packaging industry. “It’s the network that best fits packaging,” he maintains.

Why? “It satisfies not only the end-user requirements but the original equipment manufacturer (OEM) requirements as well. The packaging OEMs have been using networks for many years—they have a motion network, they have a drive network, they’ve had to use some safety networks, and because of that, they’ve had to work with different media, different protocols, and they all require different programming and configuration tools, even multiple communication cards in the programmable logic controller (PLC). By going with Ethernet, you collapse all that into one network, and that simplifies their machine design.”

From an end-user perspective, says Hannah, Ethernet helps users more easily integrate equipment into their facilities and “helps them to realize the full efficiency potential of their machines.”

Rick Rey, business development, electric drives & controls, for Bosch Rexroth Corp., a Hoffman Estates, Ill,, vendor, summarizes the benefits of that efficiency. The prime advantage, he says, is “being able to connect your primary with your secondary and tertiary packaging machinery so that when a new product, or a different size or package for the same product, is coming through, the necessary axis movement changes and other modifications are all made seamlessly. This helps you operate with maximum efficiency.”

Of course, there are different approaches to Ethernet, as Jeremy Bryant, networking business manager for Siemens Energy & Automation Inc., another major automation vendor in Alpharetta, Ga., makes clear. “As far as the connectivity goes, Ethernet is really the key. When you start looking at your control network, though, it needs to be able to handle all the possibilities of your application while still allowing the openness of Ethernet. Some networking options may be Ethernet-based, but if all they allow on that cable is the protocol for that particular application, be it motion or whatever, then you’re losing the whole point of Ethernet.”

That’s why, he says, Siemens opts for Profinet, the Ethernet protocol controlled by the organization that oversees the Profibus standard. Importantly, Profinet permits a degree of determinism, facilitating real-time operation.

Safety first

Safety, in the face of disruptive network issues and the sorts of intrusions that bedevil personal computers, is another point of divergence. Proponents of Profinet such as Bryant point to various safety features built into the protocol. Sometimes, though, vendors seem to shrug off network safety concerns, saying that information technology (IT) departments are quite capable of handling any issues that arise—after all, that’s their job. To a skeptic, this approach may seem uncomfortably similar to assurances that the big banks won’t make risky investments; after all, managing money wisely is their job.

B&R’s Muehlfellner is a skeptic. “I’m not a believer in having everything on a single Ethernet network,” he says. “I’m talking about a situation where you have your corporate systems, your PLCs or your PACs (programmable automation controllers), your drives and your I/O (input/output) all on the same Ethernet network. Technology now makes that possible, but I don’t think it’s the direction to go, first, because it requires tremendous configuration effort, and secondly, because I believe it’s a somewhat volatile solution. There should rightfully be some concern from end-users about having everything on a single network.”

Instead, Muehlfellner favors having corporate computers on some form of standard Ethernet, with plant floor equipment linked via a real-time network. For this, Muehlfellner and B&R favor Ethernet PowerLink, which adds time slicing and polling features to standard Ethernet in an effort to make it more suitable for plant floor operations.

“Ethernet PowerLink allows for very precise, deterministic data exchange between a PLC and I/O and other intelligent devices,” he maintains. With the controller acting as a gateway, plant and enterprise, in Muehlfellner’s estimation, can then conduct all necessary interchanges in relative safety, aided by communications technology such as OPC, an open connectivity standard.

The diagnostic advantage

Ironically, Muehlfellner feels that unnecessary security concerns may be hampering one of connectivity’s key benefits: remote diagnostics. “Increased machine-to-machine communication helps in many ways, but one of the areas I see ...