Chassis Expansion for PXIe Linux RT Controller Using Thunderbolt™

Some NI PXI controllers have two built-in Thunderbolt™ 3 ports for remote control of another PXI chassis directly from the PXI controller. This article explains how you can use NI PXI controllers for chassis expansion via Thunderbolt™ in NI Linux Real-Time. For Windows, use Thunderbolt™ Control Center from the Start Menu.

Hardware Requirements

Controller Supported as Upstream

• PXIe-8861
• PXIe-8881

Chassis Supported as Downstream

• 2-slot PXIe-1090
• 5-slot PXIe-1083 
• PXIe-8301 and any NI PXIe chassis

To control Thunderbolt™ in Linux RT, use tbtadm (Thunderbolt™ management tool). This utility comes as a part of the Linux RT image, so no additional installation is required.
 

Authorizing Connection

1. Power up the downstream chassis before the upstream controller is switched on.
2. Access the terminal of the controller by connecting a monitor and a keyboard, or via Secure Shell (SSH). 
3. 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 you only need to run it once. If the upstream controller is restarted, the downstream chassis will connect automatically.
      • To approve a Thunderbolt device for a single connection, use tbtadm approve --once <route string>
4. The LINK led indicator (MXI on PXIe-1090) will turn from solid amber to solid green, indicating that the connection has been established. 
5. You can now detect the downstream chassis and modules inside it from NI Measurement and Automation Explorer (MAX). Reboot the upstream controller if it is not detected.

 

Un-authorizing Connection

1. Access the terminal of the controller by connecting a monitor and a keyboard, or via Secure Shell (SSH). 
2. Use tbtadm remove <route string> or tbtadm remove-all to remove the link.
3. Disconnect and reconnect the Thunderbolt™ cable for the change to take effect.  
4. The LINK led indicator (MXI on PXIe-1090) is now in solid amber, indicating that the connection is not established. 

 

Additional Information

• NI recommends that you connect only one chassis per Thunderbolt Port.
• The Thunderbolt authorization settings can be changed via the Thunderbolt Configuration Submenu in the BIOS. Refer to the user manual of PXI controller for details.
• You cannot use GE cPCI-5565PIORC module with Thunderbolt™ enabled. Please see ERROR: Insufficient PCI Resources When Using GE cPCI-5565PIORC