For firmware version 3.1 and higher, the user role must have the function right Full Access assigned in order to modify data on the PLC. If only read access is required, the function right Read Access is sufficient.
An introduction to user management and access control with TIA Portal V19 can be found here.
Note
All Engineering Rights in the TIA Portal project, used to set up the hardware configuration or perform other operations, do not apply to tools of SIMATIC AX!
Only the function right Full Access is required to download successfully, or the right Read Access for read operations like the compare command.
If you are using the legacy legitimation mode or older firmware versions, you will need the password for Full Access to download unless you have enabled Full access (no protection) for evaluation purposes. Otherwise, the password for Read Access is sufficient for read-only access.