Just because it's invisible, please don't be prejudiced against wireless. Granted, the pathways between its transmitting and receiving antennas are intangible, so they can seem unstable, unreliable and unsafe. However, wireless devices have been gaining increasingly solid communication and security protocols, and implementing continuously evaluated signaling, switching and addressing functions in recent years. Many users, integrators, developers and suppliers believe these capabilities make them even more reliable than physical cables.
"Today's wireless market is growing at about a 16% annual growth rate, and it's maturing at the same time," says Vibhor Tandon, product manager for OneWireless wireless network infrastructure products at Honeywell Process Solutions. "There are more choices of wireless-enabled instruments and solutions, and they're easier to use, so more big-name users are open to adopting them. Honeywell's devices include multinode wireless gateways and access points in one box and its field device access points (FDAPs) that consist of separate wireless gateways organized by a wireless device manager (WDM).
"FDAPs and a WDM create a high-speed Ethernet backbone with less latency that can reach the field faster and allow users to think about using wireless for control and safety too. Wireless can even support network health because its devices can show signal quality on a daily basis. Last year, we launched our redundancy feature, which combines two WDMs that are able to talk and work as a pair in redundant mode and connect to redundant FDAPs."
Sarah Prinster, marketing vice president at Apprion, reports that "Cost savings from wireless can help, but so many people have wireless networks in their homes, and this mainstream acceptance is helping wireless to gain acceptance on plant floors. Still, security can be a challenge, and IT staff often don't know that wireless needs to be applied in process control applications in the field. So it's important to get them on your wireless development team early so everyone will be able to buy in and learn to use wireless effectively."
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To handle the convergence of wireless networking standards such as Wi-Fi (IEEE 802.11) and ZigBee (IEEE 802.15.4), some developers are combining these capabilities into unified devices, according to Doug Bellin, global senior manager in the manufacturing and engineering division at Cisco. "Besides launching our access points, including those with 802.11a-n and ISA100 standard functions built in, we offer the Cisco Clean Air solution, which consists of a self-configured, self-healing wireless backbone that constantly compiles updated views of the local networking environment," Bellin says. "It checks for hotspots or overlaps where wireless activity is especially high, shows potentially rogue access points and identifies other issues."
Rob Snyder, product manager for the network infrastructure group at Rockwell Automation, says he looks at wireless as a progression and extension of previous networking solutions, such as the fact that EtherNet/IP is built to work with IEEE 802.11. "EtherNet/IP is standard, unmodified Ethernet, so it can contain data from the different CIP protocols, but it can still go over the regular TCP/IP transport layer, which is important because wireless manages its packets at this layer," he says. "These connections are also secure because 802.11 had security organically built in as part of its Wi-Fi Protected Access 2 (WPA2) section."
All of today's standard wireless communications are now encrypted, while the WirelessHART standard (IEC 62591) is also time synchronized, so it has built-in security that's always on, adds Neil Peterson, DeltaV product marketing director at Emerson Process Management."WirelessHART devices also go through several rounds of third-party verification and certification to make sure they can't be broken into," he says. "However, WirelessHART is a device-to-device protocol, so there are no viruses.
Wi-Fi is a bit harder because people use it, so passwords and other security policies are needed to prevent attacks and make sure it will run reliably. Another advantage of wireless is that a hacker has to be located close to a facility to try to access it, but generally they don't go out to physical sites. Overall, wireless was developed with better protections than wired systems, so the Internet makes wired systems more vulnerable than wireless."