PCI eXtensions for Instruments (PXI) is a modular instrumentation platform designed specifically for measurement and automation applications.
PXI delivers a rugged, PC-based, and high-performance measurement and automation system. With PXI you benefit from the low cost, high performance and flexibility of the latest PC technology, together with the benefits of an open industry standard. PXI combines standard PC technology from the CompactPCI™ specification with integrated timing and triggering to deliver a rugged platform with a big performance improvement over older architectures. This has made PXI the industry standard for measurement and automation applications.
PXI was developed in the 1990's, collaboration between 68 manufacturers resulted in the adoption as an industry standard in 1998. The PXI Systems Alliance, of which Amplicon are proud to be a member, governs the PXI standard and ensures it continues to take advantage of the latest technology developments. This allows PXI users to put systems together choosing hardware from a number of different manufactures without the fear of non-compatibility. There are over 1150 products available today which makes PXI the preferred platform in today’s demanding test market.
What are the Benefits of PXI?
Rugged Design
PXI is based on the CompactPCI physical design that uses front loading cards, with top and bottom support rails for extra stability. This means that PXI cards can be installed or connected to signals more easily than traditional computers. PXI systems have cooling fans mounted at the base of their chassis to blow air vertically over the PXI cards, which gives improved temperature ratings.
These features deliver a rugged industrial platform to base your test solution whether it is a bench top, rackmount or portable solution.
PXI Timing And Synchronisation
The main differences between PXI and CompactPCI are the timing and synchronisation features. This is achieved with eight shared bus lines, a low-skew star trigger and a 10MHz system reference clock that allows multiple cards to work in conjunction with each other. By physically looking at a CompactPCI and PXI card, the difference is very clear. Both versions share the same connector for the PCI bus but PXI has an additional connector that contains the timing, synchronisation and local bus feature.
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Below is an example application using the PXI timing and synchronisation feature is a system fitted with multiple data acquisition cards which requires all analog signals to be measured at the same time. The PXI star trigger connects to all the data acquisition cards in the chassis. This ensures that all A/D converters take their samples at the same time
Reduce Space
Traditional instruments such as oscilloscopes and waveform generators traditionally use GPIB or VXI as their interfaces to automated test systems. When fitted in a 19" rack cabinet, this makes the whole system very big. Using PXI allows you to replace a basic instrument like an oscilloscope with single slot PXI oscilloscope card that sits inside the test system, along with a PXI signal generator and PXI data acquisition cards, thereby significantly reducing space. Some applications may still require VXI hardware or instruments with a GPIB interface. A PXI system could still be used for these applications, since we are able to offer PXI boards with GPIB and VXI interfaces on them.
PC Look and Feel
Using PXI gives you the familiarity of a PC based environment that allows you to run software designed for Microsoft Windows or Linux. PXI is based on PC technology so you get the bus speed of 132MB/s throughput whereas conventional test systems using VXI and GPIB offer much slower transfer rates. The latest PXI developments mirror PC developments, with the introduction of PXI Express which utilises the high speed PCIExpress bus.
Current test systems based on a PCI platform are able to migrate to PXI very easily. Software written for a PCI card is able to run an equivalent PXI board, making PXI the natural choice for new test systems.
