We Have a Hitachi seiki ca20 with the same problem.
Go to set function key and set item A line 7 and switch the dot to the richt side and key input.
Go to the parameters and change line 9001 to 00000001
that works with our hitachi with the seicos III controller.
Note: we are missing the pc and ladder software discs. those files have the extension .A until Q (A to D is the pc software and E until Q is the ladder software.