Cause : STO ACTIVE comes when drive attempt to run the motor with the Safe Torque Off active. This safety feature is designed to bring the motor to a safe stop in case of an emergency or fault condition.

STO ACTIVE (Safe Torque Off Active) fault in a Parker AC30 drive indicates that the Safe Torque Off (STO) function has been activated. The STO function is a safety feature that disables the drive’s output and prevents the motor from producing torque, effectively stopping the motor safely and reducing the risk of unexpected motion.

Possible Causes and Solutions:

1. STO Function Triggered:

   • Cause: The STO function may be activated intentionally as part of a safety procedure, such as during maintenance or in response to an emergency stop.
   • Solution:
     • Verify safety procedures: Confirm whether the STO function was activated intentionally for safety reasons. Follow appropriate safety procedures to clear the fault and restore normal operation.

2. Safety Circuit Issues:

   • Cause: Problems with the safety circuit or wiring can cause the STO function to be triggered erroneously.
   • Solution:
     • Inspect safety wiring: Check the safety circuit wiring and connections for any issues, such as loose or damaged wires. Ensure that all connections are secure and correct.

3. Faulty STO Switch or Relay:

   • Cause: The STO switch or relay used to activate the STO function may be faulty or malfunctioning.
   • Solution:
     • Test and replace components: Check the STO switch or relay for proper operation. Replace any faulty components as needed.

4. Drive Configuration Issues:

   • Cause: Incorrect drive settings or configuration related to the STO function can cause the fault to be activated.
   • Solution:
     • Review configuration: Verify the drive’s configuration settings related to the STO function. Ensure that they are correctly set according to the system’s requirements.

5. Interference with Safety Circuit:

   • Cause: Electrical interference or noise affecting the safety circuit can cause the STO function to activate unexpectedly.
   • Solution:
     • Mitigate interference: Use shielded cables and proper grounding to reduce electrical noise and interference. Ensure that safety circuits are protected from external influences.

6. Drive or System Faults:

   • Cause: Internal faults within the drive or the overall system may trigger the STO function.
   • Solution:
     • Inspect the drive and system: If external causes are not found, inspect the drive and system for internal faults.