A standard platform for modular instrumentation based on compactPCI. PXI uses a 4U high chassis which 3U instrumentation modules slot into. The chassis backplane carries a PCI bus which allows communication between the modules and either a controller in the chassis or a host computer, connected to it via a bridge. The PXI platform includes extensions specially designed for instrumentation, such as dedicated timing and triggering lines added to the backplane to synchronise different modules together.
The PXI standard is maintained and promoted by the PXI Systems Alliance.