TECH TALK

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Expanding Test Capabilities Using PXI

The next significant evolution of PXI is here. Board level products and useful intest solutions are now available. These products offer functionality that was previously only available in instrument form just a few years ago, and the test environment associated with electronic circuits and systems has changed dramatically over the years. General test programs, used as a starting point for applications, can easily have specific test parameters added to make the program usable for many different projects. No longer is it necessary to develop a base program due to the commercial availability of standard test programs.

PXI products now offer various functions, including switching and high speed digitizing. Just a few years ago test engineers faced the concern of not having enough space to house instrument level products in their test solutions. Today, most of the essential testing functions are available on a PXI card. While there are still stand alone instruments available for testing functions, if a PXI card meets the test requirements, it is likely that the test engineer will opt to purchase a lower priced card that will take up less space in a system. Today’s PXI systems are versatile, compact and offer a variety of functions at a lower cost than its stand-alone counterparts (Figure 1).

We are now entering an era where PXI controllers can easily be changed to fit target applications. Customizing a PXI controller increases the flexibility of a chosen test system. Engineers no longer require multiple controllers or expensive add-on cards for multifunction applications. Enhancements can include modifying the BIOS configuration to enhance controller performance, and increasing the amount of memory to more smoothly run programs in real time.  Customizing a PXI controller increases the flexibility of a chosen test system.  Several advantages include streaming data for use in high-speed data acquisition applications, and running multiple displays from one controller.

Figure 1.

Onboard CPUs are also increasing in flexibility as well. There are controllers on the market today that use low-power mobile technology, such as Pentium M processors. These processors provide higher processing power while consuming lower overall power. In turn, because power consumption generates heat, this will eliminate another problem of undesired heat. Another feature of new generation CPUs is programmable processor speed, called speed stepping. This allows the user to change the speed of the processor by changing the setup features in the BIOS, and gives the user the flexibility to change the processor speed to get the maximum throughput for the application. Giving the engineer options and parameters that are variable will offer more choices to complete the task at hand. 

Emerging hardware features are removing constraints that test engineers have faced for years. Lower power consumption increases the possibility the controller can be reconfigured for use in testing multiple products. When more time is spent optimizing each test, it will in turn save time, reduce overall test costs, and extend the life of test stands in the constantly changing test and measurement industry.  

A lower cost per board has been a goal of many in the test world since the inception of the PXI form factor. The smaller 3U form factor adopted by the PXISA consistently takes advantage of new emerging technologies. The smaller board size requires lower power consumption, yet continues to increase onboard functional density. However, occasionally systems require large amounts of I/O, and it would appear that the functionality of the system is limited, due to the maximum number of slots in a PXI system, and the size of the PXI board. In this situation, it is possible to link together multiple chassis using a technology such as Star Fabric. This allows the expansion of the number of slots in a PXI system. Both systems can work in tandem using the controller that resides in the original system, because the backplanes are electrically tied together.  Thus, the entire system is running with a single controller, and one test system with expanded I/O slots will communicate the test results directly to the test hub supervisor. If you need expanded I/O functionality, linking together two systems can get you the results you desire.

PXI systems are also using technology that has been utilized in other test systems. Technologies such as IEEE-488 interfaces will also plug into PXI chassis and connect outside instruments into the system. This helps create a bridge between proven past technologies and the current emerging technologies being deployed in new systems today. Thus, higher performance and the utilization of both current and past technologies can be implemented simultaneously.  Seamless transition shortens time to market, and some of the functions developed on the PXI platform are used to create such a transition. With the above trends and technical direction continuing, PXI platforms will continue to reduce the cost of test while reducing the time to market for test.

ADLINK Technology manufactures systems and I/O products for test and measurement, motion/vision, and communication industries. Their extensive product line includes single board computers, data acquisition modules and solutions, analog/digital I/O, remote data acquisition modules, and real-time distributed I/O systems in the PXI, PCI, and CompactPCI form factors. For more information, visit the ADLINK Technology website at: www.adlinktech.com

(Reprinted from PXI Technology Review)

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