The case for wireless on the plant floor

Thomas Pridonoff, like a lot of manufacturing executives, sees the potential benefits of running plants on wireless networks. But unlike most of his peers, Pridonoff believes he has found a wireless networking technology that will perform as expected in a production environment.

Pridonoff is president of Accent Plastics, a Corona, Calif.-based company offering design, manufacturing, and product assembly services to companies selling plastic-based products for a range of industries. The wireless network he plans to install is based on a pair of technologies that some industry experts believe could ultimately make plant-floor wireless networks as common as those found in office settings.

These technologies offer a two-pronged solution to the reliability problems that scare most manufacturers away from the idea of wireless plant-floor networks. One technology—a wireless networking standard with the odd-sounding name of ZigBee—addresses the fear of signals from a plant-floor network getting crossed with those from wireless networks elsewhere in the building, or even in nearby facilities. The other technology, wireless mesh networking, is expected to eliminate the plant-floor equivalent of dropped cell phone calls: signals being interrupted before reaching their intended destinations.

Quite understandably, these are major concerns for manufacturing companies, where even the smallest amount of equipment downtime can be catastrophic.

"Manufacturing is an industry that IT people see as not suited to wireless data networks," says Harry Forbes, senior analyst with Dedham, Mass.-based ARC Advisory Group. "That's about to change. Wireless networks will bring more applications to the plant floor, including things like voice-enabled systems."

Accent Plastics is poised to benefit from this phenomenon. The company is a longtime user of Enterprise IQ, an ERP package aimed at midsize companies that also contains a production- monitoring component. The vendor of this system, IQMS, offers two versions of the production-monitoring application: one that sends batch updates on the status of production processes, and one that transmits that data in real time. Late last year, IQMS introduced a wireless version of the real-time production monitoring application.

Accent Plastics, currently using the batch version of the Enterprise IQ production-monitoring program, plans to move to the real-time version sometime this year, and Pridonoff says Accent will adopt the wireless option as well. Among the advantages Pridonoff sees are cost savings from not having to run wire to connect the real-time monitoring sensors to production machines. He also likes a new feature that IQMS added to the wireless solution, which allows connecting a light pole to a wireless network, making it easier to monitor the status of jobs as they are running.

When a machine is set to produce a certain number of parts per minute, for example, a signal traveling from the machine will cause a light atop the pole to flash certain colors reflecting the pace at which a job is running. A flashing green light indicates the job is running at the expected pace. Blue signals the job is running faster than expected; red says it is running slower than expected; while amber means the machine is down. The light also can be set to signal when the job is done.

That last option is especially appealing to Pridonoff.

"Overrunning jobs is a major problem for plastics manufacturers," he says. "This will address that issue. We definitely see the value of going wireless."

The IQMS solution incorporates networking gear from Crossbow Technology, which has harnessed both ZigBee and mesh networking technology to create a series of products. The combined Crossbow-IQMS solution starts with attaching small hardware devices called "motes" to production machines.

Crossbow defines motes as a class of technologies containing robust, versatile sensors that are small enough to be deployed over wide areas.

The motes deployed with the IQMS production-monitoring application are equipped with wireless networking cards and antennas. They collect information from production machines and relay it to a central gateway, which ultimately transmits that data to the Enterprise IQ database. Because these motes are part of a mesh network, they don't necessarily send signals directly to the gateway. They can send signals to any other mote in the network, and they will automatically choose that option if they don't find a clear path to the gateway. When one mote receives a signal from another, it also will find the best path to keep that signal moving until it reaches the gateway. Industry experts describe the manner in which a mesh network protects against interrupted signals as forming a "cloud" over the plant floor. They also say this protective cloud makes mesh networks more reliable than other types of wireless networks.

"The wired version of Enterprise IQ has been providing benefit to manufacturers worldwide for more than a decade," says Randy Flamm, IQMS president and CEO. "The new wireless functionality is easier to use, costs less, and further supports the drive toward leaner manufacturing operations. As a single-source wireless solution, we deliver greater flexibility while still enabling cost-effective, centralized control over plant operations. The net result is improved efficiency, greater visibility, and higher levels of productivity."

Major process automation vendors like Honeywell and Emerson Process Management also are working on solutions that incorporate wireless mesh network technology.

In May, Honeywell launched its own partnership with Crossbow to integrate Honeywell's sensor products with Crossbow's wireless network interfaces, gateways, and components.

"By working with Crossbow, we provide our customers with a Honeywell wireless sensor network solution they can trust," says Pat Murray, Honeywell's VP of electronic sensing.

Honeywell's work with Crossbow has produced a three-node kit for wireless sensor network development called XBW-K2400. Designed specifically for deeply embedded sensor networks, the XBW-K2400 has all the components—both hardware and software—needed to develop, test, and implement a low-power wireless mesh network that complies with the ZigBee standard.

Honeywell also is cooperating with other leading process automation vendors to develop open standards for fully integrated wireless solutions. These cooperative efforts—coupled with customer input—led to what Honeywell calls its industrial wireless road map. Honeywell had multiple reasons for developing the road map, which outlines its strategy for building wireless plant-floor devices, according to David Kaufman, director of business development in Honeywell's Industrial Measurement & Control unit.

"We can't work without wireless networks today," Kaufman says. "Wired networks are viewed as being more reliable, but in the wake of disasters like Hurricane Katrina, where wired networks were wiped out, the first replacement communication network was wireless."

IT executives now expect wireless solutions to be reliable, secure, and robust enough to operate in any environment—including plant floors, Kaufman adds. And the Honeywell industrial wireless road map offers a path for ensuring the next generation of wireless networks lives up to those expectations. Specifically, Kaufman says, Honeywell is addressing the concerns of customers who want reliable, secure, and low-power systems in a single network that can be easily expanded.

The road map ties into evolving industrial open-source wireless standards, such as Instrumentation, Systems and Automation (ISA) Society SP100 working group, and the Wireless HART initiative."With a good solution, Honeywell could capture two-thirds of the existing manufacturing plant market—not to mention what the expansion might be—because there are many sensors in those kind of plants," says Forbes.

At one time WiFi represented the only broadband wireless technology solution. Now new wireless technologies have emerged: WiMax (IEEE 802.16; 802.16e); Ultra Wide Band; 4G; HART; SP100; and ZigBee. According to Scottsdale, Ariz.-based market research firm In-Stat, ZigBee—a networking layer built on the IEEE 802.15.4 global standard, also operating in 2.4 GHz—is the emerging reliable open standard for wireless mesh networks that manufacturing executives have been seeking.

"ZigBee is a fantastic choice for a manufacturing environment," declares Brent Hodges, VP of marketing and business development for the ZigBee Alliance, a global association of more than 200 companies—including Honeywell—working to promote the emerging standard.

"ZigBee was founded on the idea of a reliable network focused on low-power, low-resource devices," Hodges says. "In large corporate settings, you need networks that are autonomous, and they have to be reliable. That requirement fits well with industrial manufacturing. ZigBee ensures hardware and software solutions from multiple vendors will be interoperable."

Although In-Stat reports that commercial building control currently is the most prevalent application for ZigBee, Hodges believes manufacturing plant floors could benefit from a standard capable of accommodating up to 65,000 devices on a single network.

"One of the challenges of organizations like the ZigBee alliance is the diversity of interests," says Hodges. "There is interest in wireless across three major markets: residential, commercial, and industrial. When it comes to developing industrial systems and process devices, the product cycles are much longer. The products need to be validated before they are introduced to the market.

"ZigBee technology is starting to proliferate in the industrial sector, even in harsh environments," Hodges continues. "Large organizations like Honeywell—one of the early proponents of ZigBee—conduct a lot of research and development. ZigBee offers an open standard for wireless device networking, and a perfect fit with 80 percent to 90 percent of the industrial market."

Yet others are slightly less optimistic about ZigBee's potential as a manufacturing-centric wireless standard. IDC's Forbes, for example, still questions ZigBee's suitability for demanding uses in process plants.

"ZigBee technology targets building controls applications at this point, but [the ZigBee Alliance] would like to expand into more industrial applications," Forbes says. "Right now the proprietary protocols lead over the standardized protocols in terms of performance for some applications. I think things eventually will converge around some standards, but it's not settled at this point."

In the near future, Emerson and Honeywell likely will see positive customer response as they continue developing wireless offerings, Forbes concludes, but the growth of wireless devices across the overall industrial marketplace will be incremental.