Cause : Watchdog Timer Fault- A "Watchdog Timer Fault" on a Yaskawa E7 drive typically indicates an issue with the watchdog timer, a safety feature designed to monitor the operation of the drive's microcontroller and ensure its proper functioning. When this fault occurs, it suggests that the watchdog timer did not receive the expected signal or that the microcontroller failed to respond appropriately within the set timeframe. 

1. Perform a factory initialization.
2. Cycle power off and on to the drive.
3. Replace the control board.