Okuma Alarm-B 2643 READ/WRITE File open
This alarm occurs in file operation using FOPENA/B or FWRITC command.
1->FOPENA/B was used to open two or more files.
2->FWRITC was used to open two or more files.
3->The writing file already exists.
4->The reading file is not found.
5->READ command was given without opening a file.
6->WRITE command was given without opening a file.
7->File closing failed.
8->The file close command is normally specified.
9->File attribute error: the reading file is not a sequential one.
4-digits(or 3-digits)->generated error number in decimal