PXIe-8398 fiber compatible?

[Greg_f]

I have a PCIe/PXIe - 8398 system for which my 3m MXI cable is too short. Is there a Fiber cable assembly that I can purchase for these cards?

[santo_13]

I guess no, you need to buy a MXI card that support fiber optic.

Instead I would recommend getting a embedded controller, connect the controller over network as far as you need. Just you need to develop another application that runs on the controller to interact over network.

[Captain_K]

The PCIe/PXIe-8398 does support fiber optic cables. You may need to update the firmware for older hardware revisions.

https://www.ni.com/en-us/support/downloads/software-products/download.pxie-8398-firmware-and-additio...

https://www.ni.com/en-us/support/downloads/software-products/download.pcie-8398-firmware-and-additio...

The 8398 fiber cable part numbers are the following:

788302-10 (10m cable)

788302-30 (30m cable)

788302-100 (100m cable)

[Captain_K]

Something to keep in mind is that these cables only link at x4 and cannot be combined to form a x8 or x16, so there may be reduced data throughput on the system.

[BrantZ]

Where in the documentation does it say that the PCIe/PXIe-8398 support fiber optic cables? The PCIe/PXIe-8375 ARE fiber-optic compatible and state as much in the title of the Manual (Fiber-Optic MXI-Express x4 for PXI Express Series User Manual and Specifications)

[AndreasGareis]

Hi BrantZ, support for fiber cables for PXIe-839x was added recently 2023 to enable long distance mxi connections because our Gen 2 fiber solution went end of life (PXIe-838x). This information is unfortunately not included in the original 839x documentation.

[john_medberry]

Does that mean for the NI solution, in order to get x8, I have to use the x8 cables? (Is there a document reference for this?)

Or explicitly: if I connect PCIe-8398 to PXIe-8398 with two x4 cables (copper or fiber) I will only get x4 connection.  Thanks!

[Captain_K]

If you connect a PCIe-8398 to a PXIe-8398 with two x4 copper cables, the modules will combine those into a x8 link.

If you connect a PCIe-8398 to a PXIe-8398 with two x4 fiber cables, the modules will only be able to utilize one cable and therefore connect with a x4 link. It cannot combine the x4 fiber cables into larger links. 

[Captain_K]

Similarly, if you connect the PCIe-8398 to a PXIe-8398 with two x8 copper cables, you'll get a x16 link. The x8 cables are essentially just two x4 cables stuck together.

Fiber cables only come in x4 style.

The different connection options for copper cables can be found in the manual. 
https://www.ni.com/docs/en-US/bundle/mxi-express-gen3-x16-feature/page/mxi-express-gen-3-connection-...

I've asked that the manual be update to include Fiber connections options, but this hasn't happened yet.

[john_medberry]

Thanks for the explicit descriptions!