The message "RTAL" Reference frequency low threshold reached indicates a fault condition on your Schneider drive related to the speed reference it receives.

The RTAL Reference frequency low threshold reached warning on a Schneider drive indicates that the reference frequency (the frequency command or setpoint) has fallen below a predefined low threshold limit set in the drive's parameters.

1. Verify the frequency parameters set in the drive, including the reference frequency limits and scaling.
2. Ensure the motor specifications match the drive settings, particularly the rated frequency.
3. Verify that control signals to the drive are stable and within expected ranges. Erratic control signals can cause frequency fluctuations.
4. Adjust the low reference frequency threshold parameters if the current settings are too restrictive or not suitable for your application.