Wireless networking is a natural fit for manufacturing and industrial settings. Wired LAN technology has been hampered in factory and warehouse environments because of the difficulty and expense of running wire to hard-to-reach machinery. Wireless whisks away those objections, making it possible and cost effective to network not only computers but control devices and, now, even radio frequency identification (RFID) readers.
"Factories are a natural venue for wireless," says Craig Mathias, principal of the Farpoint Group, a wireless consultancy and analyst firm. "You need communications to the automation and control devices. You don't have to install all that wire, so it is much more cost effective than wired LANs."
This spring has seen several important new developments in wireless standards and architectures that hold promise for manufacturing applications. Here's your primer on the latest developments.
Wi-NG Marries RFID with Wi-Fi
Wireless pioneer Symbol Technologies Inc. (Holtsville, NY) announced in May its Wireless Next Generation or Wi-NG architecture. Based on open-standards technology, Wi-NG will enable companies to deploy and centrally manage Wi-Fi, RFID, VoWLAN (voice over wireless LAN), mesh, and Wi-Max networks on a single RF network. For manufacturers that have already deployed Wi-Fi in some capacity but have waited to invest in RFID, this is good news, according to Anthony Bartolo, vice president and general manager of wireless infrastructure and RFID for Symbol.
"Anywhere a company has wireless today but wants to deploy RFID tomorrow, they can leverage their existing architecture rather than having to deploy a separate architecture," Bartolo says. "You simply add on Symbol's RF wireless switching technology as a layer and connect the RFID readers to the RF switch. Now you have connected all those readers into a centralized architecture that can be scaled, leveraged, and secured." Symbol's centralized switching architecture allows wireless access points (APs) and RFID readers to be managed from a single point, vastly improving manageability and boosting security by allowing IT managers to set and administer security policies centrally.
Being able to add RFID to a wireless network helps companies get more from their existing wireless investments, Bartolo adds, noting that this is Symbol's fourth generation of wireless technology.
Wi-NG will serve as a platform for a company's future wireless voice and data deployments, an approach Symbol calls "Fixed Mobile Convergence." Wi-NG will provide persistent connectivity for dual-mode cellular Wi-Fi handheld devices. It will support current and emerging broadband wireless technologies, including 802.11n, Wi-Max, GPRS, and EV-DO. According to Symbol, dual-mode VoIP phones will switch back and forth seamlessly between the Wi-Fi network and the cellular carrier's network so the user can take advantage of the best available connection.
Mathias says Symbol's breakthrough is allowing multi-tasking on the wireless LAN (WLAN). "Every other type of LAN is used for multiple functions, so this should [be], too. This extends WLANs' ability to be the mission-critical networking backbone of the company," he says. Having a multi-functional WLAN platform will enable manufacturers to run functions like building security and energy management along with all the horizontal applications like voice, data, and video on the wireless network, he adds.
"Manufacturers can collapse these technologies into a single architecture," Bartolo says. "This is a much more graceful migration than trying to cater to multiple... systems with multiple interfaces and multiple users. We are taking away the complexity of deploying RFID."
Wi-NG will allow a plant WLAN to share information with enterprise applications like ERP, which run on the corporate LAN. "The plant infrastructure and the enterprise infrastructure can work together and pass information seamlessly," Bartolo says. Symbol's wireless switches have filtering capabilities, enabling managers to see just the data they need from the plant.
When it is released in October, Symbol's WS5100 wireless switch will be the first product to support the Wi-NG architecture. In the first half of next year, the WS5100 wireless switch will be extended to support RFID readers.
TSMP: High Redundancy, Low Power
Wi-Fi can be highly useful in some mobile plant applications, particularly those that involve workers interacting with equipment or bar codes. But wirelessly collecting data from sensors or actuators on the shop floor requires a network protocol that is highly redundant and supports very low power consumption.
Dust Networks (Hayward, CA) announced in May a wireless protocol called time-synchronized mesh protocol (TSMP) that it says meets these requirements. Dust's new SmartMesh-XT family of products will support TSMP and is designed to be embedded in automation control products. Emerson Process Management (Austin, TX) has piloted Dust products that support the new protocol. Dust envisions oil/gas, pharmaceutical, and wastewater treatment plants as some of the potential venues for wireless sensor networks (WSNs) using TSMP.
The SmartMesh-XT family of products includes motes that use IEEE 802.15.4 standard radios for the global market in the 2.4 GHz band. Dust Networks is working with equipment vendors, end users, and industry associations, including the wireless HART working group of the HART Communications Foundation and ISA's SP-100, to develop wireless networking standards that meet the requirements of industrial monitoring and control.
In this environment, high reliability coupled with extremely low power consumption is imperative, according to Rob Conant, vice president of marketing and co-founder of Dust. "The batteries in these devices can go five years or more. Wi-Fi can't do that," Conant says. "In this industrial environment, it would be too expensive and difficult to run power lines all over the place." With TSMP, he says, "you deploy the system and it starts collecting the data."
As its name implies, TSMP uses time-synchronized communication based on time division multiple access (TDMA). All nodes share a common sense of time, ensuring that they communicate the data within the specified time window, Conant says. TSMP is capable of frequency hopping, which means it can "jump" back and forth among different frequencies, avoiding interference, he says.
Every node on a TSMP network can function as a router, which promotes high availability and is self-organizing, meaning it is capable of discovering and establishing links to its neighbors. "The TSMP protocol has built-in redundancy," Conant says. "It uses mesh to the edge so every node is capable of routing. If there is frequency interference, it can move over to another frequency channel. It does that automatically."
WSN technology such as TSMP is significant for manufacturers because it can help them get at information they could not otherwise reach. "There is a lot of information trapped on devices today. The ability to monitor wirelessly brings the cost of monitoring down so much, the number of monitoring points in plants will increase significantly," Conant says. That is good news for plant executives, as more data from the shop floor may add up to better decision making.
WLANs Are the Future
It will take a while for WLAN technology to catch on among manufacturers, but wireless will become ubiquitous in the industry within a few years, Mathias says. "The factory moves fairly slowly. It took many years for numerical control to take over. But we expect wireless networking to become the norm on the factory floor within the next decade. It's convenient, cost effective, and provides the same access and security as wired networking."