PXI Matures
Written by Tom Lecklider, Senior Technical Editor
Newer standards are particularly well suited to certain types of test applications. For example, because LXI does not restrict module form factor, large switching matrices are much more easily constructed in this format than in a smaller PXI chassis. Similarly, AXIe features six times the area and power of a standard 3U PXI module so it is inherently better adapted to housing high-power, complex circuitry.
Nevertheless, enhancements continue to be made to the PXI standard and new modules introduced. The PXI Systems Alliance (PXISA) website lists many of the alliance member companies and the types of modules they provide.1 The National Instruments (NI) website has similar information in a list of PXI third-party products.2 A PXI module classification chart based on these two sources is shown below.
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Predictably, many new modules improve upon older instrument specifications by being more accurate, lower cost, higher speed, or lower noise. However, innovation is not a zero-sum game: At the same time that the performance of existing types of products is being upgraded, different kinds of PXI modules also are appearing.
This process goes on all the time but has accelerated in recent years. A look at a November 2000 issue of the VXI and PXI Newsletter showed the early emphasis was on 6U products to compete with VXI.3 Of course, the larger 6U size also was necessary for many functions because circuit miniaturization and integration were a long way from today’s levels. During 2000, GenRad introduced a 6U mainframe chassis, and Geotest-Marvin Test Systems launched the 6U 100-MHz GX5150 Digital I/O Tester.
A 2007 PXI, Test & Technology Resource Guide included the views of the PXISA President Loofie Gutterman on the first 10 years of PXI as well as a series of interviews with industry leaders organized as an article by Bob Stasonis.4 Mr. Stasonis had written a similar story in 1999, and the contrasts between the two are important.
In 2007, Geotest’s Senior Product Marketing Manager Mike Dewey said, “The 1999 article…on the future of PXI standards alluded to the emergence of 6U PXI. As we know now, the adoption of 6U has never matched that of the 3U form factor.” He went on to say that Geotest had been successful partly because the 6U format existed, and in addition, both Geotest and GenRad had been more comfortable initially in adopting PXI because of the option to use either 6U or 3U.
However, as Mr. Stasonis cautioned, the articles contain a wide range of opinions. Steve Krebs, director of engineering at KineticSystems, forecast 6U growth in his 2007 interview. “The next five years will see additional requirements and growth in 6U PXI. As single-platform system requirements increase, the 6U PXI form factor will be the vehicle to construct such systems.”
On the same topic, David Owen, business development manager at Pickering Interfaces, added, “6U PXI has apparently failed to establish dominance in the larger test market…. PXI will need to look at new applications going forward to see if the added real estate will help it address higher I/O count and asynchronous testing requirements.”