PXI Express Compatibility

The PXI Systems Alliance (pxisa.org) recently defined a modification for PXI modules. Modified PXI modules provide future compatibility for systems incorporating PCI Express signaling in PXI. Previous versions of these modules had two large PXI connectors. In the modified PXI Express compatible DMM, the top connector has been replaced with a smaller connector. You may notice a series of regularly spaced holes in the printed circuit board that are not used by the smaller connector.

Modified PXI modules are supported by new hybrid PXI chassis slots that can accept either future PXI Express modules or existing modified PXI modules. To provide future compatibility, modified modules do not include the pins used to implement 64-bit PCI and local bus. NI PXI modules do not implement 64-bit PCI. The following functionality is preserved in the smaller top connector:

• All PXI chassis accept modified PXI modules.
• Product specifications are the same.
• No software changes (application or driver software) are required.
• Modified PXI modules are compatible with existing PXI timing and PXI triggering capabilities.
• The speed and capability of all PXI communication is unchanged.

PXI Express compatible DMMs do not support SCXI control and triggering via the backplane of a PXI/SCXI combination chassis.

PXI Express compatible DMMs are capable of SCXI control and triggering in an NI PXI-1010/1050 chassis using external cabling with an NI SCXI-1357/1358/1359 communication backplane. PXI Express compatible DMMs are not capable of controlling SCXI in an NI PXI-1011/1052 chassis. You can still accomplish SCXI triggering when using the NI PXI-1011/1052 chassis by cabling from the DMM to the SCXI module front panel.

For more information on SCXI control and triggering using a PXI/SCXI combination chassis, reference KnowledgeBase entry 3V07KP2W. Refer to ni.com/support to access the KnowledgeBase.