Cause : STO fault comes when STO1 and STO2 signals are disconnected simultaneously. The STO function is a critical safety feature designed to remove or limit torque output from the drive, effectively stopping the motor to prevent accidents or damage. When an STO fault occurs, it indicates a problem with the safety system that needs to be addressed.

"E47.04" in inovance MD800 drive indicates that the drive has failed to execute the STO function correctly. STO (Safe Torque Off) is a safety function that is used to quickly and reliably stop the motor in case of an emergency. 

Troubleshooting Steps:

1. Check Safety Circuit Wiring:

   • Inspect Connections: Verify that all wiring and connections related to the safety circuit are secure and correctly installed.
   • Look for Damage: Check for any signs of damage or wear in the wiring and connectors.

2. Verify STO Input Signal:

   • Check Signal Integrity: Ensure that the STO input signal is present and stable. Measure the signal with appropriate diagnostic tools.
   • Review Wiring: Confirm that the wiring for the STO input signal is correct and free from faults.

3. Review STO Configuration:

   • Check Parameters: Review the STO-related parameters and settings in the drive’s configuration. Ensure they are correctly set according to the safety requirements.
   • Reconfigure Safety Functions: If necessary, reconfigure the safety functions and settings in the drive.

4. Inspect Safety Components:

   • Test Safety Relay: Check the functionality of any safety relays or components involved in the STO circuit. Replace any faulty components if needed.
   • Verify Component Health: Ensure that all components in the safety system are operational and correctly configured.

5. Examine External Safety Devices:

   • Check Devices: Verify the operation and configuration of any external safety devices connected to the drive. Ensure they are functioning correctly.
   • Inspect Wiring: Ensure that wiring to external safety devices is secure and correct.