Editing PCI eXtensions for Instrumentation (section)

==Overview==
PXI is designed for measurement and automation applications that require high-performance and a rugged industrial form-factor. 

With PXI, one can select modules from a number of vendors and integrate them into a single PXI system, over 1150 module types available in 2006. A typical [[Rack unit|3U]] PXI module measures approximately {{nowrap|100 x 160 mm}} (4x6") in size, and a typical 8-slot PXI chassis is 4U high and half rack width, full width chassis contain up to 18 PXI slots.

PXI uses PCI-based technology and an industry standard governed by the PXI Systems Alliance (PXISA) to ensure standards compliance and system interoperability. 

There are PXI modules available for almost every conceivable test, measurement, and automation application, from the ubiquitous switching modules and DMMs, to high-performance microwave vector signal generation and analysis. 

There are also companies specializing in writing software for PXI modules, as well as companies providing PXI hardware-software integration services.

PXI is based on [[CompactPCI]], and it offers all of the benefits of the [[Peripheral Component Interconnect|PCI]] architecture including performance, industry adoption, [[Commercial off-the-shelf|COTS]] technology. PXI adds a rugged CompactPCI mechanical form-factor, an industry consortium that defines hardware, electrical, software, power and cooling requirements. 

Then PXI adds integrated timing and synchronization which is used to route synchronization clocks, and triggers internally. PXI is a future-proof technology, and is designed to be simply and quickly reprogrammed as test, measurement, and automation requirements change. 

Most PXI instrument modules are register-based products, that use software drivers hosted on a PC to configure them as useful instruments, taking advantage of the increasing power of PCs to improve hardware access and simplify embedded software in the modules. The [[open architecture]] allows hardware to be reconfigured to provide new facilities and features that are difficult to emulate in comparable bench instruments. 

PXI system data bandwidth performance easily exceeds the performance of the older [[VME eXtensions for Instrumentation|VXI]] test standard. There is debate within the technical community as to whether newer standards such as LXI will surpass PXI in both performance and overall cost of ownership.

PXI modules providing the instrument functions are plugged into a PXI chassis which may include its own controller running an industry standard [[operating system]] such as [[Windows 7]], [[Windows XP]], [[Windows 2000]], or [[Linux]],<ref>{{Cite web|last=PXI Systems Alliance|date=March 20, 2020|title=PXI-2 Software Specification Rev. 2.6|url=http://www.pxisa.org/userfiles/files/PXI2_PXISW_r26.pdf|access-date=January 23, 2023|website=PXI Systems Alliance Specifications|publisher=PXI Systems Alliance}}</ref> or a [[#MXI link|PCI-to-PXI bridge]] that provides a high-speed link to a desktop PC controller. Likewise, multiple PXI racks can be linked together with PCI bridge cards, to build very large systems such as multiple source microwave signal generator test stands for complex [[Automatic test equipment|ATE]] applications.

[[CompactPCI]] and PXI products are interchangeable, i.e. they can be used in either CompactPCI or PXI chassis, but installation in the alternative chassis type may eliminate certain clocking and triggering features. So, for example, you could mount a CompactPCI Network interface controller in a PXI rack to provide additional network interface functions to a test stand. Conversely, a PXI module installed in a CompactPCI chassis would not utilize the additional clocking and triggering features of the PXI module.