Rugged PXI Backplanes / PXIe Backplanes

PXI (PCI eXtensions for Instrumentation) is a computing format, based on the CompactPCI interconnect standard, that is commonly used for the development of systems for testing, measurement, automation and signal processing.

PXI backplanes are printed circuit boards that fit inside a PXI chassis and provide physical and electrical connections between plug-in modules and the rest of the system. They use the PCI bus for communications, providing high bandwidth and low latency compared to older technologies. The backplane may allow 3U or 6U sized modules and cards to plug into it, with some allowing a mixture of both. This modular approach to design allows military test engineers and developers to make use of a wide range of COTS hardware from a variety of developers.

Applications

Military applications for the PXI format include acquisition of data from sensors and instrumentation, signal processing for radar and communications systems, and testing of avionics. One of the main upgrades to standard CompactPCI that PXI includes is an integrated timing and hardware triggering feature that makes it especially suited to these applications.

PXI Backplane Design

PXI backplanes are designed such that up to eight modules can be plugged into a single bus segment. If one of these slots is used for a bridging module, multiple sections of eight can be daisy-chained together. While this arrangement can theoretically allow thee backplanes with up to 31 slots, the 19” rack format mostly commonly used for PXI chassis will put a practical limit on the number of modules that will be less than this.

PXIe Backplanes

PXIe (PXI Express) is a further extension of the PXI format that uses the more advanced PCIe standard. These backplanes use a serial interface instead of a parallel bus architecture, allowing for significantly faster data speeds. They may also provide hybrid slots that offer backwards compatibility with PXI modules.