以太网继续扩大其自动化的影响力，涵盖了越来越复杂的设施中的更多设备。随着这些网络的增长和自动化设备依赖更多的通信，网络管理人员正在改变其网络基础架构以处理更多的流量。
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.
“以太网在整个自动化设施中都渗透到地板上，”约翰·F·沃兹尼亚克（John F. Wozniak）说。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 theEtherCAT 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 atRockwell 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 forPhoenix Contact（www.phoenixcontact.com）。“他们知道他们需要计划网络以使其尽可能安全。越来越多的公司正在使他们的信息技术小组参与推出工业网络。”
这部分是因为管理者对安全性有更广泛的看法。保护方案可以防止员工犯错，这可以改善正常运行时间。这个概念增加了传统的恐惧对黑客。
“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."
