“I have talked to customers that have actually used up their bandwidth,” Kaufman said. These customers began to install wireless implementations and incrementally used up their entire band. “Were those the most important things that you wanted to use wireless for in your plant?” Kaufman asked the customer. “No,” the reply came. “They just kind of snuck in.”
Every company needs a wireless strategy, said Kaufman. “What’s most important for your company? What are the applications that you want to do? Wireless sensors? Fine. But do you want wireless handhelds, too? Fine. But in time are you going to have the bandwidth?”
“It’s a strategic decision, not a tactical decision,” said Kaufman. Forward-thinking companies are creating wireless governance teams, whose missions are to assess all of the potential wireless applications within their plants and to select those that are going to be truly impactful for the business.
As much as engineers would like to control decisions over wireless, in the end each individual application will have a businesswide implication. “Don’t go technology up, go business down and then look at what technology works for you,” Kaufman said. “It’s about tradeoffs. You can’t do everything.”
A company’s wireless model is not “flat,” echoed Schweitzer of ExxonMobil. “It should really be a 3-D model. Anybody who doesn’t take a look at this as a top-down problem will very shortly run into a problem with their network.”
A 3-D model is fully conscious of the company’s IT systems and requirements, Schweitzer noted. “You have to try to see a wireless landscape within a wired world.”
Wireless and Wired
A wireless strategy must be executed with a plant’s wired networks in mind. Wireless systems will never replace wired, particularly for control applications, said Ed Ladd. Wireless technology is advancing to the point that it may be able to handle some “soft” control responsibilities, he says, but there will always be limitations (such as data security issues) to wireless control.
You need to continue to use wired and wireless and implement whatever has the lowest business risk, Ladd added. “You will get immediate benefit from deployment of wireless technology,” he said, “but make sure you’re using it in the right way and you’re choosing what’s best for you.”
Current Wireless Standards
IEEE 802 (802.11, 802.15)—the most developed and popular (and oldest) of the standards organizations; “Everybody in the industrial supplier community is using 802.11 in some way,” says Harry Forbes of the ARC Advisory Group. 802.15 is the basic international standard for sensor networking.
ZigBee Alliance—a commercial consortium of vendors looking to capitalize and commercialize the IEEE 802.15.4 technology. After 2 or 3 evolutions, ZigBee has now gravitated towards the application of advanced metering. “All electric and gas meters in North America are going to be updated in next five to 10 years and they want to be part of that,” Forbes says.
HART Communication Foundation—a 15-year-old organization that has commercialized the incumbent standard of smart field devices.
IETF/IPSO Alliance—both promote the use of Internet protocol for sensor networks.
ISA—working on a number of different standards for wireless and seeking collaboration with other standards organizations.
TinyOS Alliance—standards used by academics who prefer an open source model that allows them to collaborate with colleagues around the globe
Bluetooth SIG—new implementation of Bluetooth (low-power Bluetooth) that will have traditional Bluetooth plus low-power application which may have some implementations in the sensor area.
Proprietary technologies (ANT, Z-Wave, others)