When multiple measurement data sets need to be merged, this can be done in three steps. The only requirement is that all measurement data sets were recorded with the same setup.
1. Select multiple DXD files => multi-file export => confirm export.
2. The exported data files now have the extension "exp" => "filename_exp.dxd". Select all and load.
3. Go to "Export", here are all the channels from the loaded files . Note, the files will only be merged after the export. The filename will indicate which files are loaded.