xxxx 0001

Invalid Command

Beckhoff · TwinSAFE Logic FB

What does xxxx 0001 mean?

An invalid or unrecognized command was received over the FSoE connection. This indicates a potential communication protocol mismatch or a corrupted command transmission. Unresolved, this can prevent proper safety control and lead to system downtime or an unsafe state.

Common Causes

  • Received an invalid command instruction.
  • Command code is not recognized by the system.
  • Data format of the command is incorrect.
  • Transmission error corrupted the command.
  • Command sequence is out of order.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the firmware versions of both FSoE master and slave devices are compatible.

  2. 2

    Check the FSoE configuration in the engineering software for correct command mapping and parameterization.

  3. 3

    Inspect the communication wiring (Ethernet cable, connectors) for damage or interference causing data corruption.

  4. 4

    Temporarily monitor FSoE communication traffic with a network analyzer to identify the source of the invalid command.

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Verified technical data. Last updated: March 2026

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Source: Beckhoff TwinSAFE Logic FB