Based on the CompactPCI 3U standard the PXI (PCI eXtensions for Instrumentation) enhancement was defined especially for the measurement user. In this specification additional lines for measurement purposes are defined. There is a high-quality 10 MHz reference clock, as well as a star trigger and a trigger bus. The Spectrum boards support all these features, most notably with the help of the reference clock and the star trigger module for an easy combination of products – including those from different companies.

Supported PXI Features

The following PXI features are supported by the Spectrum cards of the MX series:

• PXI Reference Clock: by software command the supplied 10 MHz PXI reference clock can be used as base for clock generation.
• PXI Star-Trigger: by software command the card can accept the star trigger line as trigger signal. A separate star trigger card is needed.
• PXI Trigger Bus: each Spectrum PXI card can use PXI trigger line 0 to 5 as a trigger input or can output its internal trigger signal to one of the lines.
• Slot-to-slot local Bus: not supported.

Compatibility

The Spectrum PXI cards run in a plain CompactPCI 3U slot as well as in a dedicated PXI 3U slot. If using the MX series in a plain CompactPCI slot the PXI features will not be available. Due to mechanical reasons PXIe hybrid slots need a special option. See more details on PXI hybrid slots here.