Serious discussion of wireless sensor industrial networks has been going on for over ten years. It's about time we stopped and asked: Where are we with this technology? Where are we going? And what do we need to get there? The answer to the last question is interoperability.
Where Are We?
When compared with its wired cousin, wireless networking's cost and flexibility advantages have led growing numbers of providers to develop the necessary hardware and software to propagate the technology. The rush to bring products to the industrial market has resulted in a better understanding of the technology and its application and improvements in its overall reliability–a major hurdle for broad adoption. At the same time, the hardware has become less expensive and more widely available, and there is a greater appreciation of the types of software required to realize wireless' full potential.
Because of these improvements in quality, cost, and selection, wireless sensor networks have gained greater acceptance in the field of industrial automation, setting the stage for the technology's next growth spurt.
Where Are We Going?
As more (and larger) wireless sensor networks are deployed and people become more familiar with the technology, end users will try to apply it to new uses and demand new capabilities. Paralleling these demands, the number of wireless vendors has seen phenomenal growth, with the muscle of industrial instrumentation powerhouses (e.g., Motorola, Honeywell, Eaton, and Intel) pushing development of wireless technology. Now that end users have a greater choice of vendors that can deliver high-quality wireless networking hardware and software, and with the increasing deployment of larger networks, the call for multi-vendor systems and real interoperability grows. If wireless communication technology is to make the next leap forward, the industry has to move away from proprietary systems to networks composed of equipment of different vendors that can communicate and work together.
The primary tool to bring about interoperability is the standard. As available technologies have been tested by real-world applications, one has boiled to the top, identified by growing acceptance as the most effective: IEEE 802.15.4. What is need for interoperability, though, is a true standard for the application layer (Layer 7 of the OSI Model).
ZigBee has long been pitched as the standard best suited for industrial wireless sensor networks. But of late, it seems to have ceded its position and shifted its attention to building automation.
Rising to take ZigBee's place, the HART Communication Foundation is developing the wireless Hart specification. And while it has a number of major players supporting it, its long-term viability has yet to be proven.
The most likely source of a standard that will advance the cause of wireless interoperability is ISA's SP100 standard, which addresses the issue directly. For proof, look for a final standard and compliant products in 2008. It can't come too soon.