More utility plants and factories are turning from proprietary networks to Fast Ethernet connectivity for process control systems, now that the technology provides high performance at off-the-shelf prices.
Cisco Systems Inc., joining a handful of niche vendors that harden switches for harsh environments, this week is unveiling a hardened Fast Ethernet switch, the Catalyst 2955.
The Washington, D.C., waste-water treatment plant is slated to upgrade its process control network later this year and will deploy a mix of Cisco switches, including the Catalyst 2955, according to Carl Staab, manager of communication technology at Emerson Process Management, Power and Water Solutions Inc., in Pittsburgh.
Emerson, which builds and integrates process control systems for the power and water industries, has tested the switch.
Many areas of Washingtons waste-water treatment plant are too contaminated with dirt or chemicals for deploying traditional Fast Ethernet switches, Staab said. "In the chlorination tanks, you have a nasty atmospheric environment, so the equipment ends up in a sealed cabinet thats not air-conditioned," he said.
Process control networks that carry communications between devices on a factory floor require redundancy because they cannot tolerate latency. They must be resistant to any disruptions that could be caused by dust, heat or vibrations, Staab said.
The Catalyst 2955 withstands high temperatures and is passively cooled—it doesnt come with cooling fans. "With the extended temperature range, our customers insist on the removal of fans," Staab said.
The hardened switch is one-third the size of the same box built for installation in an office closet.
In manufacturing, there are nine standards for process control systems, but Fast Ethernet is quickly becoming the top choice, said Manrique Brenes, product manager for the Catalyst 2955. Process control equipment makers are increasingly building Ethernet ports into their gear, Brenes said.
Some plant managers have found creative ways to install Ethernet switches in temperature-controlled enclosures in the midst of manufacturing, said Brenes, in Irvine, Calif. "Essentially, they were deploying a refrigerator on the factory floor, and that is costly, and it is bulky."
The new switch will be available this month, priced from $2,100 to $3,600, depending on configuration.