Design News, April 2013

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A potential application class is where there is a requirement been paired with," Gardner said. for system-wide monitoring such as a call-for-parts system, for He said engineers are sometimes concerned with noisy devices example, that delivers a tote of parts to a location. Wireless is ofsuch as variable frequency drives (VFDs) operating in the same ten used on forklifts, so that the driver can have an indicator and area. Noise can reduce the range of the signal, but not signifireal-time feedback, which identifies which areas are out of parts. cantly. The wireless system has a very narrow band that it is opSince the forklift is mobile, wireless offers a clear advantage. erating within. Frequency-hopping, spread spectrum technology Many manufacturing facilities are looking to create flexible layouts where production can be laid out for specific needs depending on their product mix. To collect information from a machine used in the process that might be moved on a periodic basis, wireless works well since you can move the machine without a need to rewire it. One potential application concern is system reliability, but Gardner said that has been a focus of the design process. The signal used is extremely robust, powerful, and provides 10 to 100 times the range of a WiFi-based system, and also has built-in all of the characteristics of a PLC-based level network. This includes time-out mechanisms, CRC checks, and a pre-defined state for the output in case a link is lost. For years, these techniques have been used in PLC level networks and have also been built into the wireless protocol. With its built-in site survey, which reports signal strength, if everything is set up properly and within range to guarantee good signal strength, the system is as reliable as a wired solution. It also provides immediate indication if communication is lost to a part of the system, and has been designed with the reliability and determinism issues firmly in mind. The system can also implement a system heartbeat where wireless devices check on a regular basis, every five seconds for example. If the devices don't check in, those devices can be reset to a pre-defined state to fail in a predictable manner. Banner Engineering has a lot of experience with the wireless system technology, but the breakthrough with the Q45 is a combination of low power operation, fast response, and the way it has been implemented as a tightly defined product. The FOR DYNAMIC PRECISION APPLICATIONS: unit provides the sensors, batteries, power OUR METAL BELLOWS COUPLING. management, and the wireless system all in a single housing. "All the user needs to do to establish communications is bind it to a gateway. Since there can be multiple gateways and devices in a single area, communications RW-AMERICA.COM THE COUPLING. only occur with devices that they have THE PERFECTIONIST [w w w. de s ig n n e w s . c o m ] ap ril 2013 Auto mAtio n & Co ntr o l / A s up p le me nt to De s ign n e ws S21

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