NI PXI Embedded Controller Design Advantages

PXI embedded controllers from National Instruments provide a high-performance, yet compact in-chassis embedded computer solution for your PXI or PXI Express measurement system. These embedded controllers come with an extensive feature list, such as the latest integrated CPUs, hard drive, memory, Ethernet, video, serial, USB, and other peripherals. By providing all of these peripherals on the controller’s front panel, overall system cost is minimized because you don’t need to purchase individual PXI or PXI Express cards to gain similar functionality. The controller comes pre-configured with NI LabVIEW Real-Time or Microsoft Windows and all the device drivers pre-installed.

In this paper, learn about the NI design features that give NI the ability to deliver highly reliable, high-performance controllers.

When National Instruments releases a new PXI embedded controller, it offers the controller shortly after major computer manufacturers such as Dell or HP release computers featuring the same high-performance embedded mobile processor. This trend illustrates the company’s design expertise and commitment to providing the instrumentation industry with high-performance PXI embedded controllers that take advantage of the latest PC technologies, such as the Intel Atom, Core i7 processor, or Xeon processor. Also, because NI has been in the business of releasing PXI embedded controllers for over 15 years, the company has developed a close working relationship with key processor manufacturers such as Intel and Advanced Micro Devices (AMD). For example, NI is an associate member of the Intel Embedded Alliance, which offers access to the latest Intel product roadmaps and samples.

In addition to computing performance, I/O bandwidth plays a critical role in designing instrumentation systems. As modern test and measurement systems become more complex, there is a growing need to exchange more and more data between the instruments and the system controller. With the introduction of PCI Express and PXI Express, NI embedded controllers have met this need and now deliver up to 24 GB/s of system bandwidth to the PXI Express chassis backplane.

^{Figure 1: NI PXIe-8880 Embedded Controller, featuring the 8-core Intel XeonE5 processor, is ideal for high performance, high throughput, and computationally intensive test and measurement applications.}

As the PCI Express standard evolved to PCI Express 3.0, PXI Express continued to take advantage of new features. The NI PXIe-8880 embedded controller, uses the advancements of PCI Express technology to offer one x8 and one x16 Gen 3 PCI Express links for interfacing to the PXI chassis backplane.

^{Figure 2: National Instruments takes advantages of the PCI specification as it continuously evolves to provide more data bandwidth.}

Using the NI PXIe-8880 embedded controller with a PXI Express chassis, such as the NI PXIe-1085, provides total system data throughput from of 24 GB/s. With this high bandwidth, you can now easily implement computationally intensive applications that demand high-throughput rates such as next generation wireless communication design and prototyping, RF record and playback, noise mapping, and digital video test.

NI PXI and PXI Express embedded controllers feature a variety of I/O connectivity to interface to stand-alone instruments or peripheral devices. I/O offerings include up to two USB 3.0, four USB 2.0 ports, dual-Gigabit Ethernet, GPIB, serial, two display ports for dual monitor support, and parallel ports. Each of these ports directly translates to cost savings because they negate the need to purchase PXI modules that provide this functionality. In addition, you can optimize the usage of the available slots in a PXI chassis because you now can use the slots to place measurement modules instead.

^{Figure 3: Easily expand your system with the extensive front panel peripheral I/O.}

Some embedded controllers also have variants with an optional ExpressCard slot that extends I/O. By using low-cost, off-the-shelf ExpressCard adapters, you can easily add I/O such as industrial communication buses (CAN), additional USB ports, or a CompactFlash card reader to the embedded controller. You can also use this ExpressCard slot to provide eSATA ports for high-speed and high-capacity data storage to meet complex data-recording and playback application needs.

As the needs of test, measurement, and control applications evolve, NI continues to expand the accessories portfolio of the PXI embedded controller to ensure optimal performance. For memory-intensive applications, NI offers the PXIe-8880 embedded controller with memory upgrade options up to 24 GB RAM. In order to align with the memory upgrade options, Windows 7 64-bit is available on the highest performance controllers to ensure your applications can fully access all available system RAM.

Not only can you choose from memory upgrade options, but National Instruments also provides a variety of hard drive upgrade options. These options range from high-capacity standard hard disk drives (HDD) to solid-state drives (SSD). When storing instrumentation data from your application, it is convenient to store to the onboard HDD on the embedded controller. To ensure enough space for all desired data, National Instruments offers an option to upgrade your standard HDD to a larger capacity HDD, for example 500 GB HDD, to maximize storage space.

For harsh environments where you want to operate the controller or store data, SSDs are also available. These drives do not have any moving parts; therefore they significantly reduce risk due to mechanical failure, resulting in improved system reliability. They can also withstand extreme shock, high altitude and vibration, and other harsh operation environments. Besides better tolerance for harsh operating environments and increased reliability, SSDs provide lower read and write seek times as compared to standard rotating medium hard drives. This translates to higher sequential and random data read and write rates. Applications using SSDs experience faster application load times and overall test-time savings due to faster file I/O.

It is critical to ensure that modern instrumentation systems are highly reliable under demanding operating conditions. For this reason, NI offers extended-temperature and 24/7 operation versions of its PXI embedded controllers. These embedded controllers use a more rugged hard drive designed for reliability in low- and high-temperature extremes and 100 percent duty cycle, 24/7 operation. The hard drives used in standard versions of these embedded controllers work in an operating range of 5 to 50 ^oC and can operate at 20 percent duty cycle for eight hours/day, five days/week, similar to PCs and laptops. The extended-temperature and 24/7 operation versions have an operating temperature of 0 to 55 ^oC and can be used for applications that require continuous operation, up to 100 percent duty cycle, for 24 hours/day, seven days/week. You can also choose a solid-state hard drive instead of the standard, rotating-medium hard drive to further improve the reliability of the entire system, particularly in harsh environments. Because of this unique design consideration by NI, you can deploy PXI-based instruments in more challenging applications.

PXI embedded controllers continuously feature the latest processors on the market. To ensure that the embedded controller offers optimal performance over the entire operating range, NI performs extensive thermal, mechanical, and electrical testing to ensure that the CPU in an NI PXI embedded controller doesn’t throttle its processor performance when used in extreme environments. Ensuring the CPU’s proper performance and reliability increases the overall reliability of the PXI system. NI accomplishes this by using its expertise in developing embedded controllers and applying techniques such as advanced design simulation and designing custom heat sinks.

^{Figure 4: When comparing the NI PXI-8108 to an alternate PXI vendor, the alternate vendor operates at 25 °C hotter than the NI PXI-8108 at low activity.}

To ensure determinism and offer even higher reliability, NI offers PXI embedded controllers that run a real-time OS and LabVIEW Real-Time Module software instead of standard Windows OSs. Systems running Windows or other general-purpose OSs cannot guarantee the completion of a certain task in a specified time because the OS shares the processor with other system processes running in parallel. With LabVIEW Real-Time running on the embedded controller, the entire processor is dedicated to running your specific application, which ensures deterministic and reliable behavior.

For an automated test or instrumentation system, space can often be a major constraint. PXI embedded controllers and the PXI platform, itself, offer high performance in a much smaller footprint compared to other instrumentation platforms. For example, for a test application that requires a digital multimeter (DMM), oscilloscopes, power supplies, function generators, and switches, the space requirement for a standard benchtop instrument-based solution is about 6 ft³. A PXI-based solution for the same application consumes about 0.67 ft³.

A common misconception regarding the small PXI footprint is that this space savings comes at the cost of performance. It is important to understand that the PXI platform is capable of offering this space savings not by lowering performance but by modularizing the system. Every traditional boxed instrument requires a separate processing circuitry system, display, and physical interface. For PXI-based instrumentation systems, these functions are designated to specific components shared among multiple instruments. A PXI embedded controller acts like a central processing and control hub for all the different instruments in the PXI chassis. It also provides a human interface through its connectivity to external peripherals such as a video monitor, keyboard, and mouse. Software running on the embedded controller interacts with the different PXI instruments to define the actual functionality of the test system. With these standard functions designated to the embedded controller that offers state-of-the-art performance, PXI instruments need to contain only the actual instrumentation circuitry, which provides effective performance in a small footprint.

^{Figure 5: Embedded controllers occupy slot 1 of PXI and PXI Express systems.}

In the case of an unlikely embedded controller hardware malfunction, the design of the NI embedded controller allows for quick field replacement of critical components such as the hard drive and the memory without affecting the warranty. To recover faster from a software malfunction, all Windows-based PXI embedded controllers from National Instruments contain a hidden partition that holds a factory-state image of the hard drive. You can use this image to quickly restore the controller to its factory installation state. With the newer controllers, you have the ability to create custom images of the hard drive that you can use later, instead of the default factory image, to recover from a software crash. These NI PXI embedded controller features help reduce system downtime and ensure maximum productivity of a PXI-based automated test or instrumentation system.

Along with system recovery, to improve the serviceability of the PXI embedded controller you can quickly access in-ROM diagnostics for the hard drive and memory without requiring external third-party tools. By running these diagnostics, you can determine if you need to replace the hard drive or memory. The controller design allows for quick field replacement of critical components such as the hard drive and the memory without affecting the warranty. To ease the process of purchasing spare components, hard drive and memory upgrades are available with the embedded controller. Therefore, combining all these features significantly improves embedded controller serviceability.

National Instruments works closely with Intel to ensure features of the latest processor are incorporated into PXI embedded controllers to make certain PXI applications can take advantage of these new tools. The most recent feature that was added to the Nehalem-based processor family is Intel Active Management Technology (AMT), which provides system administrators the ability to remotely monitor, maintain, and update systems. With this feature, administrators can boot systems from a remote media, track hardware and software assets, and perform remote troubleshooting and recovery.

You can use this feature to manage deployed automated test or control systems that need high up-time. Test, measurement, and control applications can use AMT to collect data remotely and monitor application status. When an application or system failure occurs, AMT gives you the ability to remotely diagnose the problem and access debug screens. The problem is resolved sooner and no longer requires interaction with the actual system. With AMT, you can remotely update software when required, ensuring that the system is updated as quickly as possible since downtime can be very costly. AMT can provide many remote management benefits for PXI systems. This feature is automatically enabled on the NI PXIe-8135 embedded controller. 

Often to deploy test and measurement systems in classified areas, you need these systems to have an associated declassification process. Declassifying a PXI system requires knowledge of all memory components in the system including the chassis, controller, and modules. PXI embedded controllers feature nonvolatile storage in the form of a hard drive or a flash drive that retains user and system information, even after the system is powered down. Because nonvolatile storage is required for the PXI embedded controller to operate, the NI PXIe-8135 with removable hard disk drive (RHDD) offers the ability to remove this storage media so that it can be placed in a secure environment.

In addition to placing the storage media in a secure environment, the NI PXIe-8135 RHDD embedded controller adds the ability to have separate, unique software images loaded onto the same station hardware.

^{Figure 6: Easily access the hard drive through the front panel accessible hard drive carrier for removable storage options}

In 1965, Gordon Moore, cofounder of Intel, empirically stated that the transistor count on an integrated circuit would double every 24 months. This prediction, now known as Moore’s Law, has so far been upheld by chip manufacturers such as Intel and AMD and has resulted in an exponential increase in the number of transistors on a single silicon chip.

^{Figure 7: The transistor count of Intel processors has increased exponentially over the years.}

This rapid increase has directly led to a consistent introduction of newer, faster, and more efficient processors every year. Although PXI-based instruments stand to gain from these advancements, be wary of the fact that the introduction of a new processor directly relates to the obsolescence of an older one.

To minimize the impact of obsolescence, National Instruments is committed to ensuring an embedded controller is available to the market on average five years. If an extended support period is required, the National Instruments Services team works with you to create service plans that meet your specific support needs. Plans can include services such as sparing and rapid replacements; long-term repair and calibration (beyond the product’s commercial end of life); annual life cycle and obsolescence reports; and technology refresh planning with National Instruments technical resources. For those applications that can migrate to the latest technology, National Instruments is committed to offering a standard set of peripheral I/O, for example USB, Ethernet, GPIB, and serial to ensure that new embedded controllers are a close drop-in replacement for previous generation products. Therefore, while designing an embedded controller, it is imperative to choose a processor that offers the best performance and guarantees availability throughout the life of the controller.

National Instruments uses its close and long-term working relationship with the two major processor manufacturers to choose processors and chipsets for PXI embedded controllers with long-term embedded roadmaps. This ensures that these components are readily available throughout the life of the embedded controllers and for any required repair or replacement. This ultimately adds value to the embedded controller and increases the life of the overall PXI-based instrumentation system.

For more information about National Instruments PXI platform design advantages, please view the other sections of this series:

• Learn more about PXI Systems
• See PXI Controller options