National Instruments 779917-01 PXI Express Chassis

Often called the PXIe-1078, the National Instruments 779917-01 is a 9-slot PXI Express chassis made to accommodate a variety of test and measurement application requirements. It has a backplane that supports both PXI Express and conventional PXI hybrid-compatible modules and has PCI Express access to each slot. With up to five slots for traditional PXI hybrid-compatible modules and a combination of PXI Express modules in every slot, its flexibility makes it appropriate for a wide range of configurations.

There are eight PXI Express slots on the chassis, five of which are hybrid compatible. This implies that they are capable of accepting both normal PXI modules and PXI Express modules. Three PCI Express (PCIe) lines with a single-direction bandwidth of 250 MB/s each are routed as x1 links from the system slot to peripheral slots. A PCIe switch receives the fourth connection from the system slot and routes it as an x4 link. The PCIe switch then distributes x1 links to the other peripheral slots. To further improve connection, the backplane has an x1 PCIe link to a PCIe-to-PCI translation bridge.

A 10 MHz reference clock with ±25 ppm precision, less than 5 ps jitter, and a maximum slot-to-slot skew of 250 ps is provided by the 779917-01 chassis, which fully complies with PXI timing and synchronization specifications for PXI modules. To meet handshaking and triggering requirements, it also supports the PXI trigger bus. A 100 MHz reference clock with a maximum slot-to-slot skew of 100 ps, less than 3 ps of jitter, and differential accuracy of ±25 ppm are provided by the chassis for PXI Express modules. Though it lacks a system timing slot, the NI PXIe-1078 does not offer a star trigger and restricts the import/export of PXI triggers and the 10 MHz clock.

The 779917-01 is a lightweight, durable device that is perfect for portable use. It weighs only 16.6 lbs. It has a fan-speed selector with an AUTO/HIGH option for best cooling; the AUTO mode reduces noise pollution by regulating fan speed based on air intake temperature. At an ambient temperature of 25 °C, the sound pressure level is only 49.9 dBA.