C01711

Defect in a monitoring channel (Alarm)

Siemens · SINAMICS G120

What does C01711 mean?

This alarm signifies a defect within a safety monitoring channel, detailed by r2124 fault values. Causes include data cross-check errors between processors (0-2, 4-43, 58-999), difference in position actual value exceeding tolerance (p9542), differing monitoring function tolerance values (44-57), or an expired watchdog timer (1000) due to frequent F-DI signal changes. Initialization errors (1001), test stop issues (1005, 1011), cyclic communication failure (1020), or low current for encoderless acquisition (1041) can also trigger this alarm.

Common Causes

  • Data cross-check error between internal safety processors, specifically indicated by r2124 values (0-2, 4-43, 58-999).
  • Difference in position values (e.g., from redundant encoders or internal calculations) exceeding a configured tolerance.
  • Transient communication error between the safety module and the main control board.
  • Fluctuation in internal voltage supply to position monitoring components, causing temporary discrepancies.
  • Electromagnetic interference affecting the internal safety communication bus or encoder signals.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Record the specific r2124 fault value (e.g., 0, 1, 4, 58) for detailed diagnosis of the internal discrepancy.

  2. 2

    Power cycle the inverter (main power off/on) to clear any transient errors in internal memory or processor states.

  3. 3

    Verify the integrity of the encoder feedback (e.g., HTL, TTL signals) if used for position monitoring, by checking signal levels with an oscilloscope at terminals X45.

  4. 4

    Monitor internal diagnostic parameters related to processor cross-check status (e.g., r0949, r0950) for inconsistencies.

  5. 5

    Review system grounding and shielding integrity (e.g., cable shields terminated at PE) to mitigate potential EMI sources affecting internal communications.

  6. 6

    If the alarm persists and r2124 indicates a specific hardware range (e.g., values 58-999 for internal hardware), prepare for safety module or control unit replacement.

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Verified technical data. Last updated: March 2026

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