Design News, February 2013

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S E N S O R S / M AC H I N E V I S I O N DESIGN APPLICATIONS Battery-powered wireless sensors can be used to indicate the open or closed status of small pocket doors used in an airplane hangar. Cables and wires would quickly be twisted and broken by the motion of the large hangar door. Changing the Look and Feel of Factories and Industrial Environments When plant managers evaluate the advantages and drawbacks of wired versus wireless networks, they need to consider cost savings, maintenance issues, ease of installation, and configurability, uptime, and security. O One of the most interesting recent changes in industrial plants and manufacturing operations is the rapid acceptance of wireless networks that connect sensors and switches to control and monitoring systems. Based upon a proven and standardized technology — IEEE 802.15.4, this move from wired to wireless networks in industrial, manufacturing, and warehousing applications is primarily driven by the need to reduce costs, improve uptime, save energy, and improve workplace safety. Warehouses, factories, and industrial facilities are discovering that wireless networks can help reduce manufacturing and installation costs. Because 802.15.4 wireless can cover a wide area in a plant, it eliminates wiring costs and cable routing problems, while placing fewer restrictions on the location and placement of equipment. It also reduces related installation costs and time for accessories such as conduits, clips, or connectors. In many instances, wireless is the best solution for applications where traditional switches or sensors are not economically or technically feasible, such as across large open areas where heavy vehicles travel, or mounting on moving doors and equipment. Speed of installation is another factor behind the move to wireless, particularly for factory floors that need to reconfigure manufacturing and assembly lines quickly and efficiently to ensure a minimal amount of downtime. In wireless implementations, the plant manager can simply move the assembly machines to new locations and turn on the wireless network, eliminating the need to reroute cables or deal with new data cables. Maintenance and repair costs are another challenge for plant managers. Switches play an essential role in industrial and transportation controls, monitoring the position and presence of doors, booms, and valves. However, wired switches and sensors are often the cause of installation and maintenance challenges, particularly in installations subject to harsh environments or frequent flexing in the wiring. In addition, traditional wires can cause tripping hazards or may be damaged during normal equipment operation, thus causing expensive downtime. On the other hand, wireless switches help reduce maintenance costs because equipment connections are less complex. By eliminating wired sensors and switches, plant managers simplify their troubleshooting steps and reduce commissioning time. In some cases, using battery-powered switches and sensors removes the need to use any cables at all. Wireless networks also increase system reliability by eliminating the potential for continuity issues caused by wiring or connectors. Additionally, wireless devices are simpler to replace or reconfigure. For example, there is no need to disconnect and reattach wiring, which also eliminates the risk of incorrect wire attachment. In many cases, the installation of a new wireless network is less expensive and faster than replacing the existing damaged wire, which takes time to troubleshoot and replace, causing considerable downtime. T4 TREND WAT C H : SENSO R S / M A C HI N E V I S I O N / A S U P P L E M E NT TO DE S IGN NE WS F EB R UARY 2013 [www.designnews .com] Source: Honeywell BY JOSEPH CITRANO III, HONEYWELL SENSING AND CONTROL

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