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 Once the information is exchanged, the switch and monitor use it to address and encode the signals they exchange. Once established, the pairing is maintained even if the monitor loses power or a battery is replaced in the switch. This ensures a self-healing network and simplifies system maintenance. The monitor is able to automatically re-establish any dropped link to a registered switch. Replacement or reconfiguration of the devices is performed through a clearing and repairing process. The combination of addressing and encryption helps to ensure the uniqueness and security of each wireless device's channel. No two monitors or switches will have the same network address, so the monitors and the sensors/switches will not respond to signals originating from other networks. This means a monitor will not confuse signals within its network, and switches will not respond to signals intended for other switches. Even if an addressing error occurs somewhere, the network will not react to the erroneous signal because the encryption keys for decoding the message will not match. The use of encryption further ensures that no unregistered node can successfully insert erroneous signals into a network or decode signals from a network, making the network secure from both eavesdropping and hacking. Cost Savings, Greater Flexibility Using an 802.15.4 radio network to connect switches and sensors to a central controller frees industrial and manufacturing equipment developers and users from many of the costs and restrictions of wired solutions. It also expands the range of possible uses and placement of monitoring devices, making it easier and faster to reconfigure the factory floor for new product designs. As a result, the commissioning and lifetime cost of the network drops, while significantly increasing reliability and integrity. 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. 802.15.4-based wireless networks have proven themselves reliable, robust, and cost-effective for a wide range of industrial, warehousing, and facility applications. Joseph Citrano III is global product manager for Honeywell Sensing and Control. For more information, go to There's a better way to predict the future. The PHD IMPACT Sensor Predictive Maintenance Device • Minimizes unnecessary maintenance • Reduces unanticipated downtime • Detects changes in impact caused by failing equipment Productivity Tripwire • Stops production of bad parts • Flags appropriate personnel of machine crash • Indicates time and level of machine crash Benchmarking • Programmer measures impact • Monitors centripetal forces • Counts impacts or extreme vibration Programmer defines what levels of impact require a warning or a machine stop. SFP Slide For complete information visit or call 1-800-624-8511 P.O. Box 9070 • Fort Wayne, IN 46899 USA

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