Chassis Expansion for PXIe-8861 Linux RT Controller by Using PXIe-8301

Updated Feb 1, 2021

Issue Details

I am using a PXIe-8861 controller with LinuxRT. Can I connect to directly to a PXIe-8301 via the Thunderbolt ports on the PXIe-8861 instead of using PXIe-8360 and PXIe-8364 combination as recommended by this data sheet ?


Yes, the PXIe-8301 can be used with PXIe-8861 Linux RT Controller for chassis expansion.
  1. To use PXIe-8301 with PXIe-8861 Linux RT Controller for chassis expansion, the downstream chassis must be powered up before PXIe-8861 is switched on.
  2. You must then authorize the Thunderbolt connection on the PXIe-8861 to be able to see the PXIe-8301 and downstream chassis. Use the following commands to authorize the connection:
    1. tbtadm topology
      • Take note of the specific route-string, e.g. "0-1"
    2. tbtadm approve 0-1
      • This command will approve and save the connection, so it only need to be run a single time. If the PXIe-8861 is restarted, the PXIe-8301 will automatically connect.

Additional Information

  • Thunderbolt support for 8861 Linux RT has been in place since PXI Platform Service 19.0.
  • The "tbtadm" utility comes as a part of the LinuxRT image, so no additional installation is needed.
  • To approve a Thunderbolt device for a single connection, use the following command:
    • tbtadm approve --once <route string>
      • This will require the user to authorize the connect every time the PXIe-8861 is powered on.
  • The Thunderbolt authorization settings can be changed via the Thunderbolt Configuration Submenu in the BIOS. See the PXIe-8861 manual for details on these settings.