Cause : External fault 1 comes when an external condition or device connected to the drive has triggered a fault. This can be due to various reasons depending on how the external fault input is configured. 

F035 fault in siemens master drive indicate External fault 1. This means a fault triggered by an external device or signal that's connected to the drive and is preventing normal operation.

1. Check whether there is an external fault.
2. Check whether the cable to the corresponding digital output is interrupted.
3. P575 (Src No ExtFault1).