Safe torque off

What does 5091 mean?

The Safe Torque Off (STO) function is active, meaning both STO signals (IN1 and IN2) are switched off or lost, causing the drive to trip. This is a critical safety function that stops the motor for safety. The drive will not start until both STO signals are restored and all faults are reset.

Complete Troubleshooting Guide

1. 1

   Verify the integrity and continuity of all safety circuit connections to the STO input terminals.

2. 2

   Confirm that the external safety device (e.g., safety relay, PLC) is correctly supplying the STO signals.

3. 3

   Check the value of parameter 95.04 (Control board supply) to ensure stable power to the control board.

4. 4

   After resolving the cause, reset the drive from an appropriate source (e.g., control panel, digital input).