In today's manufacturing environment, systems and equipment are being asked to perform at levels not thought possible a decade ago. The intent is to push process operations, product quality, and equipment reliability, availability, and maintainability to unprecedented levels while sustaining budgetary structures that are consistent with cost reduction initiatives. In light of this, there is a demand to reduce operational and support costs and eliminate or minimize any new capital investments in plant equipment, while increasing process efficiency and revenues. In short, manufacturers are trying to invoke new measures to ensure plant performance and minimize costs, plus extend operational life of new and/or aging equipment. The only way this can be accomplished is by developing new and innovative approaches in managing plant assets.
To achieve this while adhering to strict economic constraints requires the development of new sensors, systems, and methods for interrogating, diagnosing, and controlling systems. The adage "business as usual" will not suffice in this new way of thinking. What is needed is a technology (or methodology) that can act as a unifying principle, allowing the integration (or insertion) of information-gathering sensors and/or equipment into a plant environment with little or no impact on the infrastructure. Wireless communications integrated with new sensor technologies, such as microelectromechanical systems (MEMS), can provide such a capability at a reasonable cost.
The question is: What is the expected impact on any industry segment that can be derived from this technology? The consensus among those who follow wireless research and development is that it has the potential to provide (1) a scalable cost of ownership; (2) a true plug-and-play capability for sensors; (3) an architecture that supports seamless deployment of many autonomous sensors; and (4) a structure within which a truly distributed network of intelligence sensors/systems can exist. In this sense, the architecture within which the wireless topology resides is the structure. To understand the significance of this statement, one need only consider the last 50 years' industrial communications architectures.
In the past, measurement schemes included individually wired sensors. The cost and complexity of such schemes prompted many to embrace bus architectures when they became available in the 1970s. These bus and network topologies significantly reduced the wiring and provided an opportunity to deploy hierarchical architectures that supported distributed intelligence on the factory floor. Smart sensor standards offered new opportunities for distributed intelligence by providing and supporting higher level interfaces between the sensor and data highway that allowed for levels of data abstraction. However, these standards didn't eliminate the need to wire individual sensors to data concentrators which, in turn, introduced single points of failure in the network. Alternatives provided redundant bus architectures, but cost and complexity escalated as the number of required connections increased. Wireless networks of intelligent sensors, on the other hand, can eliminate single points of failure and provide peer-to-peer communication, so cooperative sensor implementations can be cost effective. Coupled with a self-configuring architecture, these now offer a clear advantage in cost, size, power, flexibility, and robustness.
Other advancing technologies that enhance wireless networks and make them more economically viable include sensors and actuators based on MEMS geared specifically to interrogation and sensing applications. The increasing computational power at decreasing costs fuels the migration to intelligent sensors, as well. The integration of these technologies with wireless communications could provide the low-cost, intelligent, easily deployed, peel-and-stick sensor that many of us hope for in the future.
In the meantime, customer acceptance of wireless technology alone, led by the phone market, is likely to spread to industry much as today's ubiquitous PCs permeate our daily lives. Remember that it wasn't very long ago that the thought of a PC in every home was considered completely outrageous. Trends are already evident that encourage the use of sensors, software, and controls, bolstering some companies' competitive edge. This revolution will lead to a time when the factory floor data system becomes a sustainable competitive edge rather than an expense. At that time, companies will demand increased performance and reduced cost of ownership commensurate with their technical and economic goals for their company.
The Worldwide Web offers the opportunity for more information about these emerging technologies and their potential impact in sensors for manufacturing. Some of the sites available include http://sss-mag.com/ss.html and the Oak Ridge National Laboratory site, www.ornl.gov/orcmt/wireless.
