ACS880 · Primary Control Program Firmware
Loss of one of the Safe Torque Off (STO) signals (STO2). This fault indicates an issue with the second channel of the dual-channel STO safety circuit, causing the drive to enter a safe state by removing motor torque.
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Verify the specific STO2 input signal at the drive terminal for correct voltage level (e.g., 24VDC when safe torque off is inactive).
Inspect the wiring for the STO2 channel from the safety device to the drive for breaks, loose connections, or damage.
Check the external safety device connected to the STO2 channel for proper operation and reset if necessary.
Ensure parameter 31.22 STO diagnostics is set appropriately; 'Fault' or 'Warning' mode will react to single-channel loss.
Consult the drive's hardware manual for STO wiring diagrams and signal specifications to confirm correct installation.