Solid Infrastructure Simplifies Network Expansion

Fieldbus or Ethernet? Fiber optic cabling? Managed switch? These are a few of the infrastructure decisions that need to be considered.

Aw 14629 Feb Ier1

Ethernet continues to expand its reach in automation, encompassing more of the equipment located throughout increasingly sophisticated facilities. As these networks grow and automated equipment relies on more communications, network managers are altering their networking infrastructure to handle more traffic.

As the cost of adding an Ethernet link has fallen, equipment makers have added the link to less-expensive products. Though it isn’t displacing field buses, more low-level products are connecting using the ubiquitous network.

“Ethernet is permeating throughout automation facilities, going further out onto the floor,” says John F. Wozniak, automation networking specialist for the CC-Link Partner Association (www.cclinkamerica.org), based in Vernon Hills, Ill. “It’s not in sensors, but more sensors go to I/O blocks that are on Ethernet. For some things that were field bus compatible, people are replacing screw blocks with RJ-45 or M12 connectors. Things like valves or manifolds are moving from I/O blocks or field buses to CC-Link IE Field, which is a 1Gbps Ethernet Fieldbus.”

Fieldbuses will likely see use for sensors and other devices for some time. Even when those products do shift to Ethernet, some managers are sticking with their tried-and-true fieldbus software and protocols.

“One of the important concepts for the fieldbus user to understand is that just because devices use the Ethernet physical layer, it doesn’t necessitate the use of all the overhead that has to come with an Internet-based protocol,” says Joey Stubbs, a technical spokesman for the EtherCAT Technology Group (www.ethercat.org) of Austin, Texas. “Users of industrial Ethernet technology should ask how they can simplify their automation lives with efficient protocols instead of relying on complex infrastructure components as a way to add functionality to their systems.”

When several of these low-level devices connect via Ethernet, the volume of traffic will rise a bit. Bandwidth hungry devices like cameras will have a bigger impact on traffic. These increases are forcing network managers to transition to fiber optic cabling, which is no longer a complex technology that’s shunned unless there’s no alternative.

“It’s becoming much easier to install,” Wozniak says. “You plug a card into the rack, install the cable and it’s ready to go. When installers are running cable, they can put it in a conduit next to a lot of other wires and they don’t have to worry about interference.”

Once users get over fear that fiber will be difficult to install and easy to break, they often find that it can be easier to use. More automation equipment makers are offering options that make it very easy to install.

“Many switches today offer native support for fiber, which simplifies things. In the past, you had to put a converter in front of the box,” says Mark Devonshire, product manager for Stratix switches at Rockwell Automation (www.rockwellautomation.com). “Fiber is still more expensive, but when you need distance or have noise issues, it is definitely the right choice.”

As these changes occur on the physical side, managers are also changing their approach to issues like security. Administrators who once considered security as a perpetual “next week” issue are now taking time to safeguard their critical infrastructure.

“We’re seeing a lot more planning and budgeting for security, on the whole people are becoming more educated on the need for it,” says Ken Austin, Ethernet marketing specialist for Phoenix Contact (www.phoenixcontact.com). “They know they need to plan their networks to make them as secure as possible. More companies are getting their information technology groups involved in the rollout of industrial networks.”

That is partially because managers are taking a broader view of security. Protection schemes can prevent errors made by employees, which can improve uptime. That concept augments traditional fears about hackers.

“People often think security is about some bad guy, maybe a kid in the basement hacking in,” Devonshire says. “But security is more about securing the network so it continues to perform well. Usually, problems come from the good guys, employees who commit unintended errors."

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