Many network managers are turning to fiber optics to meet these demands while also gaining other benefits.
Many front office systems have already migrated to fiber, and it’s seeing increasing use as a central connection for linking the plant floor to the business network. Many companies say that it’s the best way to ensure that there will be enough bandwidth to handle growing needs.
Cisco (www.cisco.com) and Rockwell (www.rockwellautomation.com) recommend using fiber uplinks, saying it will always be faster than copper.”
“Fiber is being used fairly often in backbones,” says Carl Henning, deputy director at PI North America (www.us.profinet.com). ”We’re also starting to see it occassionally in devices. Some equipment has direct connections to fiber.”
Fiber optic connections allow distances of up to several hundred kilometers, whereas copper connections only allow distances in the 100 m range. Another benefit is that it is not affected by electromagnetic interferences. In environments where fire or explosions are likely, it’s safer than copper. For many, these benefits make fiber an obvious choice for backbones.
“I don’t think the question should be: Are there applications where you shouldn’t use fiber? The question should be: Are there applications where you should prefer copper to fiber?” says Tim Pitterling, product manager for industrial Ethernet infrastructure at Siemens Industry (www.usa.siemens.com/industry). “Fiber and copper both have their place in industrial applications. You just have to make sure to choose the best one for the application.”
Where that divide occurs, however, is not simple to determine. In many applications, fiber is seeing little use beyond the backbone link between plants and offices. It can be beneficial in demanding applications like motion control and video inspection, but copper is also often a practical solution. Networks can be segmented so these demanding functions are isolated, obviating the need to shift to fiber.
However, suppliers are pushing to make fiber more cost-effective. One of the big drawbacks for fiber in the past has been its cost of installation. However, some cable suppliers have developed techniques that eliminate many of the steps that drive up the cost of installing fiber.
“We’ve got a polymer-coated fiber, released last year, that you can just strip and clip on a connector without the gluing and polishing that’s been required in the past,” says Dan McGrath, industrial automation solutions manager at Panduit (www.panduit.com). “There’s also less waste, and you eliminate the time of gluing and polishing.”
>> Read Automation World's complete coverage: "Ethernet: It's All About the Availability".
