A7477 alarm in siemens sinamics V90 drive indicates the EPOS Target position is less than the software limit switch minus. This means a direct setpoint command is trying to send the axis past its negative software limit.
Cause: In the actual traversing operation, the target position is less than the software limit switch minus.
Remedy:
- Correct the target position.
- Change software limit switch minus (CI: p2580).
