Sparky213 (Customer) asked a question.

May 11, 2026 at 6:17 AM
No USB found to redirect in Virt-Manager when trying to connect to a Productivity-series PLC

I have Virt-Manager setup on a Framework 13 laptop running Linux Mint Debian Edition (LMDE 7) as the host, and Windows 10 LTSC as the guest VM.

 

Using the same setup, I can connect to my C-More CM5 HMI consistently without issue. However, if I try to connect to my P1-622 (or P1-550) or P2-622w ~99% of the time it won't see the USB connection for me to redirect. In the rare times it does see it, when I try to redirect, Virt-Manager will freeze. And I will have to force quit.

 

Short of picking up a Windows laptop, any ideas I can try? Networking is a work in progress.

 

Thank you

 

 

  • 3 answers
  • 65 views

  • ADC_TechnologyGroup_06 (AutomationDirect)

    Good morning!

     

    One question I would have for you on this would be whether or not you see a significant difference in behavior between a Px-550 and Px-622 PLC. I ask because they use different USB communication methods even though they both have a USB programming connection port.

     

    • Px-550 PLC's are a true USB Device (USB 2.0 I believe) and as such you'll have to make sure the right resource is shared and given permissions, i.e. udev permissions to claim the USB device, using a USB 2.0 driver, and confirming the VM has usbredir channels configured so enumeration failures aren't occurring, etc.

     

    • Px-622 PLC's are actually a USB-to-Ethernet device which may get enumerated as a network interface instead of being grabbed as USB device. On Windows you might see this as an RNDIS adapter and it will fall back to a link-local type of IPv4 address 169.254.x.y where the PLC acts as a DHCP server and assigns an IPv4 address to the PC's network adapter.

     

    Since you mention networking is a work in progress you may need to focus in this area as the Px-622 is natively using networking on either USB or it's other Ethernet ports and the Px-550 can also use Ethernet ports for programming connection too.

     

    Let us know if this direction helps you out and puts you on the right path.

     

    My AI assistant recommends the following, but I cannot verify at the moment as I don't have the right resources at hand. I believe the steps below will show the Px-622 will show up as rndis_host but cannot verify myself.

     

    Diagnostic First Steps to Recommend

    • Plug in the PLC and immediately run dmesg | tail -20 on the host — this will show exactly what driver is binding and under what USB path.
    • Run lsusb and note the VID:PID for each PLC model
    • Check ls /sys/bus/usb/drivers/ to see what USB network drivers are loaded on the host.

    The dmesg output will be the most telling piece of information here, especially for confirming whether rndis_host or cdc_ether is the culprit on the 622s.

    Expand Post

    • Sparky213 (Customer)

      Unfortunately, I was having the same issues with both the 550 and 622. I tried
      the few micro USB cables I had left (I've been phasing those out). Then to rule
      out the USB port and cables, I got the 622.

      As for the USB to Ethernet, if I remember correctly, that sounds like what the
      CM5 HMI was showing as. That used a USB 2.0 type B port. And that was detected,
      and was able to redirect to my Windows VM. Which the C-More software would
      recognize.

      I can connect to 550 to my practice bench to check out.

      I have a P2-622 on my practice bench I can use as a stand in for the P1-622.

      Thank you 
      Expand Post

  • Sparky213 (Customer)

    To expand on my previous post, through redirecting a USB Ethernet adapter, I am able to connect to my P2-622 on my practice bench. So it seems, this should be my focus for my P1-622. Though I would still like to get this working.

     

    Once I get my P1-622 connected, I will have to experiment with Virtualbox to see if get the same results, or it works as expected. The former would indicate a Linux issue, while the latter would indicate an issue with Virt-Manager.

     

    I have my P2-622 (USB to Ethernet), & my P1-550 (USB 2.0) to compare.

     

    When I get a chance to test, I will update with my findings. Hopefully that can help with compatibility (or advice what hypervisor to recommend and avoid).

    Expand Post

 

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