PXI Express Features
Benefits of PXI Express
The PXI (PCI eXtensions for Instrumentation) industry standard, an open specification
governed by the PXI Systems Alliance (PXISA), has quickly gained adoption and grown in
prevalence in test, measurement, and control systems since its release in 1998. One of the key
elements driving the rapid adoption of PXI is its use of PCI in the communication backplane.
As the commercial PC industry has improved the available bus bandwidth by evolving PCI to
PCI Express, PXI is now able to meet even more application needs by integrating PCI Express
into the PXI standard. By taking advantage of PCI Express technology in the backplane, PXI
Express increases the available PXI bandwidth from up to 132 MB/s to up to 8 GB/s for a
more than 60x improvement in bandwidth.
PXI Express maximizes both hardware and software compatibility with PXI modules. PXI
Express hybrid slots deliver both PCI and PCI Express signaling to accept devices that use
PXI communication and triggering or the newer PXI Express standard. Software compatibility
is maintained because PCI Express uses the same OS and driver model as PCI, resulting in
complete software compatibility among PCI-based systems, for example PXI, and PCI
Express-based systems such as PXI Express.
PXI Express, like PXI, leverages from the CompactPCI specification to define a rugged,
modular form factor that offers superior mechanical integrity and easy installation and removal
of hardware components. PXI Express products offer higher and more carefully defined levels
of environmental performance required by the shock, vibration, temperature, and humidity
extremes of industrial environments. Mandatory environmental testing and active cooling is
added to the CompactPCI mechanical specification to ease system integration and ensure
multivendor interoperability.
The demanding timing and synchronization requirements of instrumentation systems are met
by the integrated features of PXI Express. Not only are the trigger bus, 10 MHz system
reference clock, and star trigger bus available in PXI retained by PXI Express, but new timing
and synchronization features that include a 100 MHz differential system reference clock for
the synchronization of multiple modules and three differential star trigger buses for the
distribution of precise clock and trigger signals have been added. Differential timing and
synchronization signals provide PXI Express systems with increased noise immunity and the
ability to transmit clock signals at higher frequencies.
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PXIe-8861 User Manual
