The F01001 error code in your Siemens SINAMICS G120 drive indicates a floating-point exception. This means an error occurred during a mathematical operation involving decimals.

There are a few possible causes for this:

• Internal system issue: The fault could be within the G120's core software.
• OA application error: If you're using Optional Applications (OA) like FBLOCKS, DCC charts, or TEC charts in your drive configuration, there might be a problem with the logic or data within them.

Here's how you can troubleshoot the F01001 error:

1. Power cycle: A simple power reset can sometimes resolve temporary glitches. Turn off the drive and all connected equipment for a few seconds before restarting everything.
2. Check block configuration (FBLOCKS, DCC, TEC): If you're using any Optional Applications, carefully review the configuration and logic within those blocks. Look for any division by zero, invalid data types, or other potential causes of floating-point exceptions in your code.
3. Review parameter settings: Double-check any parameters related to speed, torque, or control loops within the G120 drive configuration. Inappropriate settings could lead to calculations exceeding the drive's limits.
4. Update firmware: Outdated firmware can sometimes have bugs. Check the Siemens website for any newer firmware versions compatible with your specific G120 model. Upgrading might resolve the issue.
5. Advanced troubleshooting: Siemens provides parameter r9999 for further information about the floating-point exception. However, interpreting this data requires specialized knowledge.