Applies To:
  • CitectSCADA 5.21 Service Pack G, 5.30

TrnAddHistory(): A read-only file attached by this function cannot be displayed.

If attaching read-only files to the current history by using TrnAddHistory() the function returns success but will not display the history data until the files are changed to read-write access.

The files are actually attached to the system but cannot be displayed until you change the access mode of the files to read write. This was being caused by the files being opened in the wrong access mode.

CIT has confirmed this to be a problem in Citect for Windows versions 5.21 to 5.30. This problem has been fixed in version 5.30 SpkA.