Beckhoff BK1120 + KL modules on Linuxcnc

Hi everyone,I am trying to get a Beckhoff BK1120 (EtherCAT to K-bus coupler) working with LinuxCNC using EtherLab (ethercat-master) and the linuxcnc-ethercat (lcec) driver.I am running into some limitations and hope someone has experience with this.Setup:

• LinuxCNC on Debian Bookworm
• EtherLab master (from openSUSE repo)
• linuxcnc-ethercat (lcec)
• NIC: Intel I210 (working fine)
• Hardware:
  • BK1120
  • KL1104 (digital inputs)
  • KL9010 end terminal

What works:

• EtherCAT master is running and stable (Active: yes, Phase: Operation)
• BK1120 is detected correctly
• Communication is stable (no frame loss, link up)

The problem:
The BK1120 does not expose standard CoE PDOs like typical EtherCAT slaves (for example EL terminals).
Instead it provides a fixed process image for the attached KL modules.Because of this:

• Standard PDO mapping via lcec XML does not work (0x6000 etc.)
• Terminal-based configs (EK1100 + ELxxxx) do not apply to KL modules
• lcec does not seem to support raw domain access for mapping the BK1120 process image directly to HAL pins

What I have tried:

• Generic slave configs with and without PDO entries
• Attempted raw mappings (not accepted by lcec parser)
• Minimal configs to bring the master up (works, but no usable I/O)
• Checking data with ethercat CLI (limited without proper domain mapping)

Current conclusion:

• BK1120 with KL modules does not fit well with lcec, which expects PDO-based slaves
• The data exists, but is not easily exposed to HAL

Questions:

• Has anyone used BK1120 with KL modules in LinuxCNC?
• Has anyone managed to access the process image and map it to HAL pins?
• Has anyone written a custom lcec extension or used another approach?

Alternatives I am considering:

• Writing a custom HAL component to read from EtherCAT master directly
• Userspace polling (not suitable for realtime CNC)

Before I give up on the BK1120, I would like to know if there is a workable solution.Any input, configs or experience would be appreciated.Thanks

Wenn ich mich Recht entsinne, funktieren die BK klemmen nicht.
Die sind das ältere Modell und verwenden ein anderes Protokoll