The F01000 error code indicates an internal software error within your Siemens SINAMICS G120 drive. This means there's an issue with the drive's internal programming or firmware.

These are the steps to correct the fault:

1. Step one: evaluate fault buffer (r0945).
2. Step two: carry out a POWER ON (power off/on) for all components.
3. Step three: check the data on the non-volatile memory (e.g. memory card). 
4. Step four: upgrade firmware to later version.
5. Final step: replace control card