F7431 fault in siemens sinamics V90 drive indicates Changeover to encoderless operation is not possible. This means the drive is currently executing closed-loop torque control and cannot dynamically switch to an encoderless state.
Cause:
For closed-loop torque control, the converter cannot change over to encoderless operation.
Remedy:
- Do not attempt to change over to encoderless operation.
- Check the encoder cable connection.
