01 January 2004
Wireless meshes with industrial automation
Enter the industrial plant manager's dream world, where he runs his facility by watching a computer screen that displays every detail of the operation. Machines and sensors tucked into every corner of the facility feed data into the monitoring and management application. He can view every machine's output, maintenance schedule, and stress and strain level. He can monitor the amount of raw material entering the production line and the amount of finished product leaving it. An alarm alerts him to unusual stress on a machine, stress that could cause it to fail during production. He runs a diagnostic on the machine, realizes it is a legitimate risk to fail, and reduces the load on it with a few strokes on his keyboard. He shifts the load to other machines, then adds an in-person inspection of the stressed machine to the regular maintenance schedule.
Now come back into the real world, where there are no overarching views of industrial facilities, and where remote management and automation are restricted to specific physical areas or production lines. The most frustrating thing about all the pie-in-the-sky dreams for industrial automation is how close to reality they are. How many facility managers and executives have dreamed about every machine in the plant feeding data back to a central control site, where it's consolidated into a single, coherent, real-time view of what's happening in every crevice? All of them. And they all grind their teeth about being so close to that dream state without being able to enter it.
They're close because the foundation for large-scale industrial automation-sensors, databases, networks, and control applications-has been around for years. Yet, there is a key piece missing: networks that can carry the data from hundreds of collection points to central repositories quickly and reliably. Industrial environments have consistently defied attempts to deploy full-scale networks that can support centralized automation and monitoring. The inherent hostility of industrial facilities to wireless networks and constant rewiring of hardwired networks to accommodate retooling and production line shifts has made large-scale networking nearly impossible. Without an all-encompassing network to carry data from hundreds of collection points to central consoles, automation is restricted to specific physical areas or production lines, rather than over the whole plant.
Within the past two years, however, advances in networking hardware and software have cleared the way for an unprecedented degree of industrial automation, and the accompanying gains in cost controls and efficiency. New wireless "mesh" networking architectures can bypass the interference and physical limitations that have restricted extensive networking in large industrial facilities. Versatile, reliable, and economical, mesh networks are the technology that can bridge facilities managers' dreams of large-scale automation with the realities of operating in harsh environments.
Whether wired or wireless, networks have a tough go of it in industrial facilities. Hardwired networks can cost as much as $10 per foot to install, and more to modify when plant configurations change. Their cost-benefit ratio never balances out.
Wireless networks make more economic sense, but they have a history of spotty performance in industrial facilities. Popular wireless networking protocols such as wireless local area networks (LANs) and Bluetooth continue to make inroads in consumer applications and offices, but they haven't made a dent on the plant floor, because they weren't designed with industrial facilities in mind. Moving metal parts and electrical activity create interference that disrupts network traffic. Most networking protocols emphasize speed over versatility and reliability, which doesn't serve them well in industrial facilities. Industrial control networks carry much less data than business networks but through harsher conditions, so reliability, adaptability, and scalability outweigh speed.
Wireless mesh networks based on new wireless protocols that favor reliability and versatility over speed combine the reliability of hardwiring with the versatility of wireless networking. Mesh networks consist of low-cost, battery-powered sensor modules and embedded networking intelligence. The modules house microprocessors, radio frequency (RF) chips, and sensors for temperature, pressure, acidity, etc., depending on their job. The microprocessors contain embedded networking intelligence based on international wireless networking standards.
Each module in a mesh network acts as a sender, receiver, and router. They are virtually immune to interference. If a transmission from a node hits a roadblock on one data path, the embedded routing capabilities relay the information to a node on an alternate path.
The same properties that enable mesh networks to bypass interference enable them to easily accommodate change, be it a retooling, expansion, or redesign, at almost no cost. Expanding hardwired systems or conventional networks costs a mint. Expanding a mesh network requires little more than installing more modules at less than $20 apiece. A company can reconfigure a mesh network in a few hours, as opposed to the weeks hardwired and conventional networks require.
Wireless mesh networks don't displace existing networks. Just the opposite: Companies that deploy mesh networks will quickly find they extract more value from their current networking investment for relatively little money. The value mesh networks create comes in pure dollars-and-cents savings, but even more important is the transformation of local plant-floor data into strategic management information. Mesh networks can unify all of the relevant data in an industrial facility-data that once supported only select pieces of an operation-and feed it into management applications that support plant managers, maintenance managers, and right up the line right to executive management. Combining data from many different sources gives facility managers insight they could never get from the fragmented views allowed by hardwired and conventional wireless networks. And it can happen in real life, not just in dreams. IT
Adrian Tuck is executive vice president at Ember Corp., an embedded wireless networking company. His e-mail is firstname.lastname@example.org.