231-A005

Controller unit not suited for FS

Heidenhain · TNC CNC Controllers

What does 231-A005 mean?

This warning indicates that the control unit (CC, UEC, UMC) is not suitable for control systems requiring functional safety (FS), as detected during a check of the safety kernel software SKERN-CC. The currently installed controller unit fulfills safety requirements according to EN 13849 but is not approved for functional safety applications.

Common Causes

  • The installed controller unit (CC, UEC, UMC) is not approved for functional safety applications.
  • Incorrect controller unit type or version installed for an application requiring functional safety (FS).
  • Mismatched hardware configuration with the safety kernel software (SKERN-CC) requirements.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the part number and type of the installed controller unit (CC, UEC, UMC) against the machine's functional safety requirements.

  2. 2

    Replace the affected controller unit (CC, UEC, UMC) with a model explicitly approved for functional safety (FS).

  3. 3

    Consult the machine documentation or Heidenhain technical support to confirm the correct controller unit required for your system's safety integrity level.

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Verified technical data. Last updated: March 2026

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Source: Heidenhain TNC CNC Controllers