MXi

MXI is a term used in automated test equipment to describe a family of high-speed interconnects that link a host computer to modular instrument chassis, such as PXI, VXI, or VME systems. The MXI interface provides a dedicated data path that carries PCI or PCI Express transactions between the host and remote instruments, enabling control and data acquisition as if the devices were directly attached to the host bus.

In a typical MXI setup, the host computer contains an MXI controller or adapter, which connects via a dedicated cable to an MXI bridge in the instrument chassis. Additional MXI devices can be daisy-chained to extend the system to multiple chassis. The MXI bridge translates host bus transactions into local backplane cycles on the remote instruments, while maintaining timing, interrupt signaling, and reset behavior.

Variants of MXI include configurations such as MXI-Express and related implementations, which use PCI Express as the transport while preserving compatibility with PXI, VXI, or VME backplanes. The technology is widely used in laboratory and production test environments for instrument control, data acquisition, and automated test sequences.

Advantages of MXI typically cited include isolation between the host and instruments, scalable expansion to accommodate more devices, and the ability to place instruments remotely from the host computer while maintaining deterministic performance. In practice, MXI competes with other interconnects based on USB or Ethernet, but emphasizes predictable timing and throughput needed for test applications.

See also: PXI, VXI, VME, PCI Express.