Edge Gateway Lab, Part 2: Installing Beckhoff RT Linux and Managing Nine Ethernet Ports
Bench installation, first-boot checks, interface mapping, and static IP configuration.
Install Beckhoff RT Linux
The Beckhoff RT Linux image and installation manual are available from Beckhoff's website. A registered account is required to download them, and the same account will also be needed later when installing TwinCAT 3. I will not repeat the download links here.
Use Rufus to write the .img file to a bootable USB flash drive. At startup, press F7 to open the boot menu, select the USB drive, and follow the procedure in the manual.
For this isolated bench test only, I enabled disk encryption and set both the disk-encryption passphrase and the administrator password to “1.” The installer does not enforce password complexity. Use strong credentials on any production or connected system.
The installation completed in under 30 seconds.
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Figure 1. Beckhoff RT Linux installer menu. |
After installation, select option 3 to reboot. Enter the disk-encryption passphrase and the administrator password to log in.
First boot and SSH access
I connected the controller's LAN1 port to a router for network access. DHCP assigned the address 192.168.3.118/24. For clearer screenshots, I used FinalShell as the SSH client for the rest of the work.
A headless build has plenty of advantages, but it is not especially friendly to a Linux beginner. I worked through the setup command by command and intentionally avoided installing GNOME or another desktop environment.
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Figure 2. LAN1 is active as eno1 with the DHCP address 192.168.3.118/24. |
Verify the operating system and hardware
Real-time kernel
The kernel identification includes PREEMPT_RT, confirming that this is a real-time Linux build.
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Figure 3. Kernel output showing PREEMPT_RT. |
CPU, memory, and storage
The following checks confirm the processor, available memory, and disk layout before adding the automation
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Figure 4. CPU information for the Intel Core i7-8665UE platform.
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Figure 5. Memory usage immediately after installation. |
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Figure 6. Storage layout, including the EFI partition and encrypted root volume. |
TwinCAT runtime status
TwinCAT was not preinstalled. The manual states that the TwinCAT runtime must be installed through apt, so I left that task for the next stage of the lab.
Map the nine physical ports to Linux interface names
The main task was determining which Linux interface name corresponds to each physical LAN label on the front panel. To avoid losing remote access, I left the interface carrying the SSH session connected. I then connected a second cable, one port at a time, to a switch or router and monitored the link-state changes.
watch ip -brief link |
The watch command refreshes the physical link state of every network interface every two seconds by default.
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Figure 7. Baseline link-state output for the available Ethernet interfaces. |
For the test shown below, I connected front-panel LAN9 to a second switch while keeping LAN1 active for the SSH session.
The link-state change showed that the front-panel LAN9 port maps to the Linux interface enp2s0.
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Figure 10. enp2s0 changes to UP when LAN9 is connected.
Assign a static IP address to LAN9
I wanted LAN9 to use the static address 192.168.10.20/24. With systemd-networkd, I created a dedicated .network file for enp2s0:
sudo nano /etc/systemd/network/10-enp2s0.network |
In nano:
• Press Ctrl+O to write the file, then press Enter to confirm the filename.
• Press Ctrl+X to exit the editor.
Restart systemd-networkd to load the new configuration:
sudo systemctl restart systemd-networkd |
Verify the result with the interface address output and the systemd-networkd status for enp2s0.
ip -brief addr |
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Figure 11. enp2s0 is configured with the static address 192.168.10.20/24.
Lesson learned and next step
The RT Linux installation itself was fast. The time-consuming problem was a typo in the [Match] section of the .network file. I did not catch it at first and repeated the configuration several times before finding the mistake.
That completes this stage. In the next installment, I will bring up TwinCAT 3 on the RT Linux system.