Redefining Instrumentation Through Open Software and Reconfigurable Hardware

Publish Date: Jun 06, 2013 | 5 Ratings | 5.00 out of 5 | Print

Table of Contents

  1. Test Is Changing
  2. National Instruments Redefines Instrumentation
  3. Elements of a Redefined Test System
  4. Redefine Your Test System
  5. Additional Resources

1. Test Is Changing

The world around us is software-oriented, and the way we interact with devices is changing. Smartphones, set-top boxes, and even automobiles are now defined by their embedded software. With this evolution, we are challenged to keep up with the pace of innovation and the resulting complexities.

Twenty years ago, testing a phone meant getting a signal. Today the design, test, and production of a mobile device involve an entire ecosystem of functionality, applications, and technology resulting in a necessarily different approach to test.

Figure 1. Increasing functionality means increasing test requirements.


Building a test system to solve today’s challenges is no longer a simple problem. Instead, it requires evaluation of expanding test requirements and an architecture that can last over time. It’s important to choose a platform that can harness the technology curve while enabling abstraction and integration.

Devices under test (DUTs) are moving away from single-purpose, hardware-centric entities with limited capability to multipurpose, software-centric entities with endless capability. Why shouldn’t your test system evolve in the same way? Make the switch from traditional instruments with vendor-defined functionality to National Instruments software-defined architecture, allowing user-defined measurements and analysis in real time. You can even extend the flexibility through the deployment of algorithms to an onboard FPGA for increased instrument performance. With a software-defined approach, the commercial off-the-shelf technology powering the latest DUTs can power your test system in the same way—optimizing your test architecture for years to come.

Watch this video showcasing the evolution of technology and how you take advantage of it every day.


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2. National Instruments Redefines Instrumentation

To fully embrace this software-defined philosophy, National Instruments has redefined the traditional testing approach with an architecture that combines PXI hardware and NI LabVIEW system design software. Through this approach, you can use technologies such as multicore microprocessors, user-programmable FPGAs, PCI Express hardware, and system design software to meet the flexibility and scalability demand for future test and measurement applications.

Figure 2. The combination of PXI and LabVIEW form a software-defined test system that scales with increasing device complexity.


PXI, or PCI eXtensions for Instrumentation, is an open specification governed by the PXI Systems Alliance (PXISA) that defines a rugged, high-performance platform optimized for test, measurement, and control. PXI combines PCI Express electrical-bus features with the rugged, modular packaging of CompactPCI and adds specialized synchronization buses. PXI is the leading modular instrumentation platform used to build compact, high-performance automated test systems for a variety of applications such as manufacturing test, military and aerospace, machine monitoring, automotive, and industrial test. With more than 2,000 products offered by more than 60 vendors, you can quickly interchange, customize functionality in software, and repurpose modules as your test needs evolve.

Figure 3. These key components make up an automated test system.


LabVIEW provides an intuitive graphical programming approach that reduces test development time through drag-and-drop graphical icons instead of written lines of code. By taking advantage of a wide variety of PXI instrumentation and platform products, including the latest technologies such as multicore and FPGAs, LabVIEW is a single software environment that simplifies integration and reduces execution time. To accelerate productivity, use a wide array of built-in math and processing functions to focus on the data and results and built-in engineering-specific controls and indicators to customize user interfaces.


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3. Elements of a Redefined Test System

According to Moore’s law, the number of transistors on a processor chip roughly doubles every two years. As a result, CPU performance roughly doubles in the same amount of time. It is common for automated test systems that apply Moore’s law through the use of software-defined architecture to see improvements of 10X or more in size, cost, and power reductions. Multicore processors, PCI Express buses, FPGAs, and analog-to-digital converters (ADCs) are crucial building blocks to a redefined test system. Harnessing these latest technologies is not a trivial task without the proper ecosystem of software and hardware components for test. NI recognizes this challenge and has continually invested in delivering a complete platform designed to use the latest PC-based technologies while ensuring rapid system development and long-term stability. By pairing PXI, a PC-based platform, with LabVIEW, the leading system design software for automated test, you can develop innovative test systems to meet challenging time-to-market and performance requirements.


Modular Microprocessors

Much of the time associated with a measurement is consumed in CPU clock cycles. Calculations required for a test can be math intensive, so a high-performance processor is important to improve test times. For this reason, a modular approach to both measurement equipment and the computational engine (PC) can keep your test system performing at state-of-the-art levels for much longer than a fixed-functionality box with a CPU dating back to your original purchase. This uses the power of Moore’s law for measurements in the same way consumers have done for decades for other processing tasks on PCs. With the modularity of PXI, you can take advantage of the latest processor improvement for your test and measurement applications by upgrading only the controller in your systems.

Figure 4. By choosing a modular hardware architecture, you can upgrade the processing element of the system over time to take advantage of the latest PC technologies and achieve faster test times.


User-Programmable FPGAs

Many DUTs require more sophisticated test methods than traditional instrumentation or even PC-based instrumentation alone can deliver. Take advantage of the low-level I/O control and parallelism available through FPGAs. FPGAs are reprogrammable devices embedded in the instrument, close to the I/O, where many of the most demanding computations need to be performed. This serves a function often impossible with microprocessors alone.

User-programmable FPGAs are available through modules for the PXI platform. You can use LabVIEW to program FPGAs with familiar LabVIEW dataflow code rather than a more cumbersome hardware description language that can require specific expertise. Using NI hardware as a part of the LabVIEW reconfigurable I/O (RIO) architecture gives you the ability to take advantage of the parallelism, performance, and reconfigurable nature of FPGAs in your test systems. In applications ranging from real-time spectral measurements to digital protocol test, FPGAs can provide a key competitive advantage and help you keep up with the increasing DUT complexity that Moore’s law continues to drive.

Figure 5. FPGAs have seen a similarly impressive increase in computational power (measured in GMACs) over the last decade compared to CPUs.


PCI Express

Many applications such as RF record and playback, electronic device validation, and high-channel-count data acquisition generate tremendous amounts of data. Traditionally, benchtop instrumentation systems such as oscilloscopes, logic analyzers, and arbitrary waveform generators have implemented limited data streaming. As instruments evolve, they may have the capability of incredibly fast sampling rates and high signal bandwidths, but the bus that interfaces the instrument with the PC to return data to the user for processing or storage is often the bottleneck. The throughput capabilities of this data communication bus directly impacts instrumentation bandwidth access and as a result, reduces overall test and measurement times. Therefore, you must use the highest bandwidth, lowest latency PC bus technology available to retain as much data in a continuous stream as possible.

PCI Express and its evolutions through first-, second-, and third-generation transfer rates offer instrumentation as a means of moving data sets quickly and efficiently to memory on the PC or to a disk through RAID implementations for post processing. As data buses like PCI Express replace the “result” buses like GPIB or LAN used in traditional instruments, you can access more information and, therefore, acquire more insight into the performance of the DUT. The PXI platform has been at the forefront of integrating PCI Express with high-performance measurements.

Figure 6. PCI Express represents the best combination of high bandwidth and low latency to address the needs of the large data sets of many applications.


Expanding Measurement Capabilities

High-performance instrumentation ensures more accurate measurement systems. In PXI, some of the industry’s highest performance instruments use the latest commercially available technology, such as ADCs from Analog Devices and Texas Instruments. Other examples include National Instruments collaboration with Tektronix to create high-bandwidth (>5 GHz) digitizers. Another area of innovation is NI SourceAdapt technology, which is featured on a variety of high-precision PXI source measure units (SMUs). This next-generation SMU technology is powered by a digital control loop instead of the traditional analog control loop. With NI SourceAdapt technology, you can completely customize an SMU response to any load to generate an ideal response with minimum rise times, no overshoots, and no oscillations. Test DUTs faster without the risk of accidental damage or system stability issues.

As commercial technology providers develop better converter technologies or instrument architectural pieces, the PXI platform has proven itself the most efficient way to get them into the hands of test engineers.

Figure 7. Deploy up to 17 instruments in the same footprint as a single box instrument.


Due to the modular approach of PXI, as devices become more complex, you can easily evolve the functionality of current instrumentation in software or change out the modules to include new instrumentation. National Instruments offers more than 600 PXI modules that are configured in software to create customized testing solutions. Because of their modularity, you can quickly and easily interchange and repurpose them to meet your test needs.


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4. Redefine Your Test System

The redefined instrumentation approach provided by National Instruments uses open software and modular hardware with key elements (multicore CPUs, user-programmable FPGAs, PCI Express, data converters, and LabVIEW system design software) to address the most demanding challenges. As instrumentation evolves to meet newer standards, more complex protocols, and higher bandwidths, these tools form the foundation of a test approach that can stand the test of time. Take advantage of this redefined approach for your next system.

Here are some examples of companies from various industries that redefined their test system by making the switch from box instruments to a software-defined approach. They realized increased software development productivity, faster test execution and throughput, lowered capital expenses, and increased scalability, which dramatically reduced their total cost of test.


Lexmark - Scalable Test System Capable of Handling High Volume and Adapting as Needs Evolve

"Standardizing on the NI platform was a strategic decision. For more than a decade, it has met our escalating needs and helped us save hundreds of thousands of dollars while helping us meet aggressive time-to-market demands. We are now deploying it globally across our supply chain."

—Global Director, Consumer Printer Division


Sony EMCS—Modular, Software-Based Approach Shortens Test Development and Test Execution

“To develop a more flexible and reliable testing system, we based our system design on NI PXI hardware and LabVIEW graphical programming software, which shortened the programming development time.”

—Koh Chee Lit, Test Engineer


Honeywell Co. Ltd, China—Reduced Test Equipment Costs, System Size, and Engineering Workload

“By developing our new FCT system with PXI and LabVIEW, we greatly reduced duplication of engineering effort and can more easily share resources. We successfully applied this solution to our production lines, resulting in stable and reliable PCB testing.”

—Wei Wang, Test Engineer


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5. Additional Resources

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