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WIRELESS DAQ


wireless DAQ as well as many other applications.” Neil Forcier, an applications engineer


with Agilent’s system products division, demonstrated the programming tools in an online video.8 He noted that while there are many PC tools available to sup- port test and measurement applications development, that isn’t the case with mobile device apps, a situation Agilent is working to change. To that end, Agilent is offering Android and iOS device pro- gramming tools that facilitate connecting to instruments, controlling data, and plotting the data they generate.


From a purely data acquisition approach, the advantages that come with Wi-Fi are huge. Jim Schwartz


National Instruments


According to Chris Delvizis, a product manager for data acquisition products at NI, the company began releasing its fi rst-generation wireless DAQ products in 2007, and the SAVE, bridge-collapse test, solar-cell assessment system, and autonomous marine vehicle applications cited in references 1 through 4 employ that technology. He added that at NIWeek 2011, NI introduced its second-genera- tion platform in the form of a one-slot NI CompactDAQ chassis that supports wireless, USB, and Ethernet buses. The new NI cDAQ-9191, cDAQ-9181, and cDAQ-9171 chassis accommodate all NI C Series modules for the NI Compact- DAQ platform and can be used in con- junction with the existing four- and eight- slot chassis. With modules designed for almost any sensor, the NI CompactDAQ platform eliminates the fi xed functional- ity of traditional sensor measurement systems and gives engineers and scientists the ability to increase productivity while decreasing overall cost.


New metal enclosures make the chassis more resistant to environmental dam- age as compared to the previous plastic sleeves. The chassis operate in a tempera- ture range of 0 to 55°C and can withstand up to 30g shock and 3g vibration. Delvizis noted that the new chassis can be used with more than 50 C Series mod- ules vs. 10 or 11 for the fi rst-generation product. In addition, multiple electrical and sensor connectivity options can be combined with any chassis to cre-


14 • EE • February 2012


ate customized systems specifi c to the needs of numerous applications. “The big change,” he said, “is the breadth of measurement modules that [the second- generation product] now supports.” Among the features, NI Signal Stream- ing technology delivers high-bandwidth capabilities that make it possible to achieve sustained high-speed and bidirectional data streams over USB and Ethernet as well as wireless buses. Zero-confi guration net- working technology simplifi es initial setup, eliminating the need for IT involvement in network setup and integration. NI-DAQmx driver software, included with each NI CompactDAQ chassis, enables engineers and scientists to log data for simple experiments or develop a complete test system in NI LabVIEW, NI LabWindows/CVI, ANSI C/C++, or Mi- crosoft Visual Studio .NET. A consistent API enables an application developed for an NI CompactDAQ wireless chassis to work with an NI CompactDAQ USB or Ethernet chassis without any modifi ca- tions to the software. In addition, all new NI CompactDAQ chassis now support the controller area network (CAN) C Series module for optimal communica- tions across various networks. Delvizis noted that each C Series mod- ule includes the analog/digital converter as well as the signal-conditioning and the connectivity features necessary to support common measurements—from thermo- couples to load cells—all in a single module package. As a result, users need not build such functions themselves or use an external signal-conditioning box. The next step beyond Wi-Fi might be cellular, and Delvizis said, “We keep our eye on all technologies, and we provide ways you can use LabVIEW to connect with a cellular network,” for example by using a hotspot card such as Verizon MiFi. And in an online video,9 Agilent’s Forcier describes how a cellular router can be used to extend measurements over very long distances. In the video, he demonstrates an iPad running the free Agilent 34972A DAQ mobile app. As for emerging hot applications areas, Schwartz at NI sees opportunities in machine condition monitoring. “MCM is quickly growing. You can watch signa- tures in the vibration data or voltage and power signatures and tell if, for example, your wind turbine is balanced,” he said. Looking forward, vendors will be seeking ways to optimize speed. Delvizis


noted that current 802.11 implementa- tions might not be suffi cient for an appli- cation involving eight accelerometers, so NI plans to take advantage of emerging 802.11ac technology with its gigabit- per-second and up data rates. Concluded Schwartz, there are many new wireless protocols, and NI wants to make sure it can adapt each to its custom- ers’ needs, whether for data throughput or very low power. Low-power wireless technology for remote monitoring will be a topic covered in next month’s EE- Evaluation Engineering.


References


1. Chalons, J-M., and Campagna, H., “Protecting the Neighborhood From Noise and Vibration With SAVE,” National Instruments Case Study. 2. Fasl, Jeremiah, “Wireless Data Acquisi- tion for a Bridge Collapse Test,” National Instruments Case Study. 3. Tan, Rodney, “Using LabVIEW and Wireless DAQ to Develop a Solar Cell Effi ciency Assessment System,” National Instruments Case Study. 4. Velasco, Francisco Jesús, “Creating a Web Wi-Fi Platform With NI LabVIEW for Remote Experimentation of an Au- tonomous Marine Vehicle,” National Instruments Case Study. 5. “Increase Data Acquisition Flexibility Using Wireless LAN,” Measurement Tips, Vol. 9, No. 4, Agilent Technologies. 6. “Access Your 34972A Wirelessly With a TRENDnet Travel Router,” Measure- ment Tips, Vol. 9, No. 4, Agilent Tech- nologies.


7. Nelson, R., “Mobile Apps Support Communications Test, Data Acquisition,” EE-Evaluation Engineering, January 2012, p. 20. 8. Forcier, N., Programming Tools for Apple and Android Smart Devices to Control Instruments, Agilent Technolo- gies YouTube Video. 9. Remote Data Acquisition Using a Cel- lular Router, Make Measurements Any- where That Has Cellular Access, Agilent Technologies YouTube Video.


For More Information Agilent Technologies www.rsleads.com/202ee-176 National Instruments www.rsleads.com/202ee-177 TRENDnet www.rslead.com/202ee-178


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