Cause : Stack Overflow comes when there might be a bug or error in the internal software program of the drive or corrupted data within the drive's memory could be causing the program to malfunction.

The fault code F0101 on a Siemens Micromaster 420 (MM420) indicates a stack overflow fault. This fault typically occurs due to a software issue within the drive's control system, where the program or subroutine execution has exceeded the available memory allocated for its stack.

Here are steps to diagnose and potentially resolve this issue:

1. Power Cycle the Drive:

   • Turn off the drive, wait for a few minutes, and then power it back on. In some cases, a simple power cycle can clear temporary faults, including stack overflow.

2. Check Firmware and Software:

   • Ensure that the drive's firmware is up to date. Check Siemens’ website or contact support for any available firmware updates that may address stack overflow issues.
   • If the drive allows for software updates or patches, ensure that the latest versions are installed.

3. Review Drive Parameters:

   • Verify that the drive parameters are correctly set for the motor and application. Incorrect settings can sometimes lead to faults.
   • Check for any unusual configurations or parameters that could potentially cause a software overflow.