High speed link harnesses processor power

National Instruments has developed a high speed serial interface offering system developers a way to add remote, CompactPCI slots to industrial computers

A new technology launched last month by National Instruments brings fast and flexible PC extension technology to PXI/CompactPCI. Called MXI-3, it gives PCs direct control of the interface via a software and hardware transparent link with speeds approaching 100 Mbytes/s over distances up to 200m. Users can now control PXI/CompactPCI modules with a PC instead of an embedded computer, thus reducing overall system cost. The technology extends existing PXI/CompactPCI systems to secondary chassis providing more slots for I/O.

PC technology combines familiar graphical interfaces with powerful hardware, thousands of choices of expansion cards, and low overall costs. For this reason, many developers wish to exploit the PC in as many ways as possible – including the application of PC technology to specific automation tasks. MXI-3 now expands the capability of PCs and PXI/CompactPCI systems by transparently linking to additional PXI/CompactPCI systems. This gives developers more I/O slots to work with and spreads the power and speed of a processor. Anytime that the PC must be separated from the point of acquisition or control, MXI-3 can provide a unique high-speed solution. Desktop PCs are also extensively used as the core of data acquisition systems. They are inexpensive, use standard software development tools and work with thousands of plug-in boards. Unfortunately for developers, the number of available I/O slots in PCs is steadily declining. Today’s PCs typically have only two to three PCI slots for expansion. MXI-3 gives data acquisition system developers the means to easily add more slots to their PCs through a transparent link to PXI/CompactPCI expansion chassis. Standard Windows operating systems and development software run unmodified. MXI-3 gives CompactPCI system developers the ability to extend and link multiple PXI/CompactPCI chassis.

Today’s data acquisition systems require higher speeds and channel counts. Biological and mechanical system monitoring can demand the most of data logging systems. For example hundreds of transducers attached to a racehorse running on a treadmill can identify a minor strain. Hundreds of pressure, strain, acceleration, and temperature transducers on complex mechanical systems, such as gas turbines and jet engines, are used. A dual-PXI chassis system controlled by a PC via MXI-3 can provide more than 800 channels of analog input to meet these demands. Many signals require signal conditioning, which is available for high-channel count applications via external SCXI chassis or by using combination PXI/SCXI chassis. For digital, more than 1200 I/O signals can be acquired with a dual PXI chassis.