PCIExtension for Instrumentation (PXI) is a specification for the use of PCI module technology in measurement technology. These PXI activities were initiated by National Instruments and over 70 other companies that belong to the PXI consortium, the PXI Systems Alliance.
The PXI specifications are open, but not an IEEE standard. They specify plug-in cardcompatibility for CompactPCI and PCI Express, transmission protocol over the backplane, form factor, triggering and timing.
In addition to the PCI bus, the PXI concept has an internal trigger bus as well as reference clock channels for synchronizing several peripheral boards, a star trigger bus for precise timing and a local bus for communication between neighboring slots. The data rate is 132 MB/s for the 32-bit PCI bus with a clock frequency of 33 MHz, and up to 256 MB/s with 66 MHz.
PXI is aimed at the instrumentation market using the PCI bus, whereas LAN Extensions for Instrumentation( LXI), which was also developed for instrumentation, is based on Ethernet. Both technologies are used to couple different measurement, control and automation modules and complement each other to a large extent. There are different modules for measurement and test tasks. For example, for DC voltage techniques, as AD conver ters and DA converters, as digitizers, for multi- channel displays, for power management, as switching frequency, high frequency or wireless modules. The PXI modules can be used in AXIe.