STO active (_ecSTO_ACTIVE)

What does 10033 mean?

This fault indicates that one or both of the Safe Torque Off (STO) inputs on the drive are not powered, occurring only when the drive is enabled. This means the safety function is active, preventing motor torque generation, which can halt machine operation for safety reasons.

• Loss of 24VDC power to one or both of the dedicated STO input terminals (e.g., X12.1, X12.2) due to a tripped safety relay or power supply failure.
• The external safety circuit (e.g., emergency stop button, safety light curtain) has activated, opening the STO input circuit.
• Incorrect wiring of the STO inputs, causing one or both to be in an unpowered state (e.g., a loose wire at terminal X12.1).
• A component failure within the external safety chain, such as a contactor or safety relay coil failure.

Click steps to track your progress.

1. 1

   Verify the 24VDC supply voltage at the STO input terminals (e.g., X12.1 and X12.2) on the drive using a multimeter.

2. 2

   Inspect the entire external safety chain (e.g., E-stop buttons, safety gates, safety relays) to ensure all components are in their normal, non-tripped state.

3. 3

   Check all wiring connections to the STO input terminals (e.g., X12.1, X12.2) for looseness, damage, or incorrect termination.

4. 4

   Reset any tripped safety relays or circuit breakers within the safety circuit that supply power to the STO inputs.

5. 5

   Confirm that the drive's internal STO status (e.g., via diagnostic parameter S10-01 (STO Status)) indicates both channels are active when the external safety circuit is closed.