3F is ? in ascii, but each number is stored as 8 bytes - this is just one of them - see the link I shared and read about binary representation of type 'double'.
It will work without the binary file when you only use the ascii file and don't pass the binary file name to the training, DWQZ710.000 - no use of any binary file.
It will work without the binary file when you only use the ascii file and don't pass the binary file name to the training, DWQZ710.000 - no use of any binary file.