Cause : Save error 1 comes when the keypad failed to transmit the COPY command to the drive within the expected timeframe. “SE1” warning occurs when the keypad does not transmit the COPY command to the drive, and does not transmit any data to the drive again in 10 ms at the time you copy the parameters to the drive.

The error code SE1 on your Delta MS300 drive indicates a "Keypad COPY error 1: Keypad copy time-out." This means there was an issue when trying to copy parameters to the drive using the keypad.

1. The causes of error are mostly communication problems between the keypad and control board.
2. Potential causes include communication signal interference and the unacceptable communication command to the Slave.
3. Check if the error occurs randomly, or only occurs when copying certain parameters (the error displays on the upper right corner of the copy page).