F00100

Watchdog Reset

Siemens · SINAMICS G120

What does F00100 mean?

A watchdog timer reset has occurred, indicating a critical software error within the drive's control unit. This signifies that the software has become unresponsive or entered an unexpected state, leading to a system reset and potential loss of control over the connected motor.

Common Causes

  • Firmware bug or corrupted firmware on the drive's control unit (e.g., CU320-2, CU240E-2), causing the software to become unresponsive.
  • Internal hardware fault on the control unit (e.g., CPU, memory module) leading to system instability or program execution errors.
  • Electromagnetic interference (EMI) exceeding the drive's immunity levels, disrupting CPU operation and leading to a watchdog reset.
  • Transient power supply fluctuations (e.g., voltage dips, spikes) to the control unit causing brownouts or unexpected resets.
  • Overloading of the drive's internal processor by excessive communication tasks or complex control functions, exceeding its capacity.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Perform a power cycle of the drive and observe if the fault persists, as this can sometimes clear transient software states.

  2. 2

    2. Back up existing drive parameters, then perform a factory reset (P0010=30, P0970=1) and reconfigure essential parameters.

  3. 3

    3. Check the drive's DC link voltage (r0026) for stability and ensure the input power supply is within specified limits.

  4. 4

    4. Update the drive's firmware to the latest stable version using STARTER or TIA Portal to address potential software bugs.

  5. 5

    5. Inspect the control unit (e.g., CU320-2) for any visible damage, loose internal connections, or signs of overheating.

  6. 6

    6. Temporarily reduce the complexity of background tasks or communication load (if applicable) and monitor for recurrence of the fault.

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Verified technical data. Last updated: March 2026

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