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For the last 25 years, engineers and scientists worldwide have chosen NI data acquisition (DAQ) devices for their high-performance I/O, industry-leading technologies, and software-driven productivity gains.
High-Performance I/O for Demanding Applications
National Instruments develops high-performance DAQ hardware in a range of applications. Specifically, NI offers a breadth of measurement modules that are flexible enough to measure any sensor, optimizes the modules for high accuracy, and provides platforms that let you precisely synchronize several modules for high-channel-count systems. In addition to standard voltage measurements, many applications use sensors to measure physical phenomena such as strain, temperature, and vibration. These sensors require signal conditioning, such as bridge completion, excitation, or amplification, so that a data acquisition device can effectively and accurately measure the signal. NI C Series, SC Express, and other select PXI modules integrate sensor-specific signal conditioning and analog-to-digital converters on a single device, which improves accuracy compared to older technologies that used separate data acquisition and signal conditioning systems. You can combine several of these modules to create a high-channel-count measurement system, and synchronize them with the timing lines in the backplanes of NI CompactDAQ and PXI chassis.
Figure 1. C Series modules provide direct connectivity to a range of sensors, and you can use them in USB, Ethernet, and Wi-Fi chassis.
Randy Recob, senior test engineer at Sub-Zero, Inc., in the United States, uses C Series modules in an appliance test station. “We chose NI CompactDAQ because of the flexibility offered by a diverse set of I/O modules and the scalability of Ethernet infrastructure,” Recob said. “We have used National Instruments data acquisition hardware and software in our test applications for years because of the measurement accuracy, system stability, and ease of use available with their solution.”
NI Data Acquisition Technologies
NI continually incorporates user feedback and state-of-the-art technologies into its products to extend their capabilities and ease of use. Two of the company’s latest advancements are NI-STC3 timing and synchronization and NI Signal Streaming technology.
1. NI-STC3 Timing and Synchronization Technology
At the core of NI CompactDAQ and X Series multifunction DAQ devices is NI-STC3 timing and synchronization technology, an application-specific integrated circuit (ASIC) designed by NI that coordinates the timing and triggering of the analog, digital, and counter subsystems and shares clocks across multiple devices.
With the timing advancements incorporated into NI-STC3 technology, Francisco Orozco, an engineer at Cummins in Mexico, was able to develop his test application more easily. “We selected X Series because we needed a device that could acquire and generate analog waveforms, and was able to retrigger its outputs, in order to test our pump coils under different conditions,” Orozco said. “This device from NI integrated the channels that we needed and made the code to perform retriggerable analog outputs very simple.”
2. NI Signal Streaming Technology
As laptops, netbooks, and mobile devices have become more popular, many customers have requested DAQ devices on external PC buses, such as USB, Ethernet, and Wi-Fi. NI developed NI Signal Streaming – which combines message-based instructions and device-side intelligence – to drive high-speed, bidirectional data streams over these external PC buses.
Figure 2. LabVIEW and NI-DAQmx driver software offer a fast and flexible way to develop test and measurement applications across a range of DAQ devices.
Magnus Wahlberg, a scientist at Fjord & Balt in Denmark, took advantage of NI Signal Streaming on an NI USB multifunction DAQ device to acquire ultrasonic signals produced by killer whales. “We developed a system based on LabVIEW software and NI data acquisition hardware that met all of our criteria,” Wahlberg said. “The recording gear consists of a linear hydrophone array, a multichannel preamplifier, and a bandpass filter connected to a digital recorder … We used the USB interface to manage large amounts of data, up to 30 to 50 GB each day, and had a dedicated software solution for logging, alarming, playback, and analysis.”
Improved Productivity Through Software
One of the biggest benefits of using a PC-based data acquisition device is that you can use software to fully customize the functionality of your measurement system to meet your exact application needs.
With a graphical interface, a suite of analysis functions, and data visualization indicators that are well-suited for automating test and measurement applications, NI LabVIEW software provides tight integration through data acquisition hardware. NI Data Acquisition devices use the NI-DAQmx driver, so you can reuse your code when you switch to a different DAQ device.
Sarita Bhat, a senior engineer at Barco Electronic Systems in India, benefits from the development speed of LabVIEW in a variety of automotive test applications. “Using LabVIEW, I can develop all of my data acquisition applications, from simple to complex, faster than with any other programming environment,” Bhat said. “The hardware interaction is easy with LabVIEW, so I can quickly acquire data, immediately analyze it, and create custom user interfaces.”
Designed for Performance
Choosing conventional measurement hardware results in lower measurement accuracy, unreliable data transfers, and inflexible instrumentation that cannot adapt as application needs evolve. Conversely, engineers that select National Instruments DAQ devices can trust their measurements today and benefit from state-of-the-art PC technologies in the future. NI designs DAQ devices for performance so that engineers worldwide can use the devices with confidence.
Sam Freed is a product manager for data acquisition at National Instruments. He holds a bachelor’s degree in computer and systems engineering from Rensselaer Polytechnic Institute.
This article first appeared in the Q1 2011 issue of Instrumentation Newsletter.
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