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AKD-C Topology Change

The AKD-C's EtherCAT topology will change when switching to firmware version 1-14. The AKD-C will have two ESCs (EtherCAT Slave Controllers) instead of one.

What does this change look like?

Comparatively, an AKD-C connected to 16 AKD-Ns (port X20B String 1, port X21B String 2), and an additional AKD-P connected to the "Motion Bus Out" port X11 looks like the following.

Old Topology New Topology
AKD-C_Old_Topology.png AKD-C_New_Topology.png

Why was this change made?

In the old topology, the delay calculation for the clock synchronization of all EtherCAT slaves on string 2 was incorrectly calculated by the EtherCAT master because the "real path" of the EtherCAT frames was different then that of the detected topology. This is corrected by the new topology.

What problems might I have if I use a firmware version below 1-14?

  • Master reports topology error
  • Set-point values are not correctly updated, which could lead to jumps in position
  • Relative following error different then the expected one (e.g., in a gantry application)
  • Probe values are incorrect

How do I solve the problems if I have firmware below 1-14?

There are two ways to update your system.

  • Recommended update path
    1. Upgrade the new AKD-C ESI file delivered in firmware version 1-14 on your EtherCAT master system.
    2. Update the AKD-C firmware to 1-14.
      Please note that the product code between 1-13 and 1-14 has changed for AKD-C firmware.
    3. Store the new topology in your EtherCAT project and check that your configuration is working.
  • Alternative update path
    1. Update the AKD-C firmware to 1-14.
    2. Rescan and use the online description for your new topology.
    3. Store the new topology in your EtherCAT project and check that your configuration is working.

What if I do not want to upgrade?

You can downgrade the AKD-C firmware to version 1-13, which includes only one ESC. Please note that you may run into the problems listed above.

How do I replace an AKD-C firmware <1-14 with one ≥ 1-14?

To replace an existing AKD-C firmware (<1-14) with a new one (≥1-14) see the solution above.

Can I run device with firmware <1-14 in parallel with others using ≥ 1-14 in one setup?

It is possible, but using the same firmware for the whole AKD-C/N system is recommended.

If you mix the firmware versions you may experience the following issues.

  AKD-N FPGA v1-13 AKD-N FPGA v1-14
AKD-C FW v1-13 You may run into the topology issues mentioned above. You may run into the topology issues mentioned above. Auto IP may work between the AKD-Ns on a single string (only between adjacent AKD-Ns on a string that have this configuration)
AKD-C FW v1-14 The EtherCAT topology issues will be fixed. The Auto IP bug (B5287) will still exist. The topology and Auto IP (B5287) issues are resolved.

If I upgrade an AKD-C to 1-14, must I also upgrade all of the connected AKD-Ns to 1-14?

It is recommended that all AKD-Ns be upgraded to 1-14, see the previous question.