Wireless Gains Ground

The sight of people talking on cell phones is certainly commonplace these days. Intel is now even aggressively marketing its new Centrino chip, which allows laptops to be mobile—even in rustic locales such as vineyards (per Intel’s TV spot). But is the plant floor next? According to a report from Technical Insights, a division of Frost and Sullivan, it is.

The shrinking cost of computational power, according to Technical Insight’s James Smith, is driving the move to distributed architecture. Embedded intelligence reduces the bandwidth required for the communications path. Customer acceptance of wireless technology, led by the wireless phone market, is likely to spread to industry, he claims, much like the ubiquitous personal computers that have penetrated the industrial markets. Trends are already evident that encourage increased use of sensors, software and controls to bolster the competitive advantage of companies.

According to the report, the integration of wireless communications with sensors is one of the next big steps for both of these technologies. The growth of the personal communications market is driving the cost of radio devices down and the quality up. The expenses associated with installing, terminating, testing, maintaining, troubleshooting and upgrading wiring is also growing, notes Smith.

The cost of wiring in a typical chemical plant, for example, is around $40 per foot. The market for new sensors in these plants is being stifled by the need to run wires to connect the new sensors to the existing plant infrastructure. The market price for fully integrated wireless sensors, which can make sensor data available through existing plant backbones, appears to be about $200 per sensor, according to the report. No one has moved to meet the need for wireless chemical process sensors, such as temperature, pressure, humidity and vibration sensing devices, Smith says.

Point-to-point wireless systems have been available in the instrumentation world for many years. The first applications were wireless modems capable of transmitting data using standard RS-232 interfaces on both ends. But Smith says restricted band allocations severely limited the number of devices that could operate simultaneously in a common area. Now, he says, the industry is spending time and money on the development of more sophisticated modulation techniques, and emerging standards have addressed many of the problems common to early systems. Wireless networks in the true sense of the term are becoming feasible through the use of advanced techniques.

But innovations alone have not brought wireless solutions to the industrial marketplace, notes the analyst. The market forces driving wireless technologies continue to offer components that exploit new technologies at astoundingly low prices and high quality. However, many engineers are not yet convinced about the reliability of wireless sensors on factory floors due to deficiencies in radio frequency operations, says Smith (see related story on p. 18). Generally, when a wireless sensor network is designed for a real-world application, engineers tend to go with a proven product, even though it may have its limitations, he notes. Wireless Ethernet and Bluetooth networks, for example, are often chosen for applications solely because they are on the shelf and have a history of being effective. “Systems scientists will tell you how ultra-wide band (UWB) was developed for wireless communications and not the factory floor,” Smith says. “But when the factory floor data systems become a sustainable competitive advantage rather than an expense to be managed, companies will demand continuously increasing performance at reduced costs.” He notes that new sensor companies are emerging to supply low-cost, high-performance and easily-deployed devices that will change the way end users view sensors and sensor systems.

Some organizations, he adds, have successfully developed components for wireless sensors but haven’t been able to produce an integrated sensor that meets operating parameters necessary for real-world use. “Bringing new technologies to bear on sensor design requires an interdisciplinary approach to design that many organizations have been unable to implement,” Smith says. Yet many have speculated that the next generation Internet will be much more sensory-interactive than it is at present. Adding the numbers of sensors necessary to address this demand will bring the sensor business to new paradigms, the analyst predicts. Preparing to make this transition today is critical to the long-term success of organizations.

Existing and emerging standards are also making it easier for the transition to ubiquitous wireless sensors, Smith notes in his report. “The IEEE 802.11 standard allowed wireless Ethernet connectivity, giving people their first view of wireless connectivity to the web. The number of requests for Internet addresses continues to grow exponentially as an increasing number of devices are becoming Internet accessible,” he says. Specifically, he explains that the IEEE 1451 smart sensor standard is making it easier to interface sensors to the network. “Extensions to 1451 are now being proposed by the committee members of the Institute of Electrical and Electronic Engineers to support wireless sensors that can be instantly accessible to the Internet—with controlled access, of course,” he says.

Many vendors have examined Bluetooth and have decided it is appropriate for their market, notes the analyst. “The trade-offs made to control cost and improve throughput at the expense of reliability may be a little scary for some engineers. However, engineers are reluctant to discount this technology simply for the fact that it isn’t ideal; many can recall the early criticisms of the Ethernet standard,” Smith says.

A number of companies are moving into this market, some with more commitment and enthusiasm than others. Most of the big players, according to the analyst, have wireless programs and products with the focus on communication networks external to the sensor. Some are packaging the sensor and telemetry systems together, but more work is necessary to bring the costs down to where the market will accept the new devices.

Markets for wireless sensors currently depend on applications where wiring is impossible or too expensive, or where operating and support costs are prohibitively high. These include environments where sealed compartments are required—vacuum processing chambers or nuclear processing facilities, for example. Others include applications in which obstacles make wired connections impossible or where the sheer number of sensors makes it impossible to access information on a timely basis.

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