Imported data can be up to 4,000 rows long by 4,000 columns wide, but no more than 255 data series can be displayed in the chart.
How?
To open a file created in another program, click the file format you want in the Files of type box. You can also type the file name extension in the File name box; for example, type *.txt to find text files. In the folder list, double-click folders until you open the folder that contains the file you want.
If you are importing a text file, the Text Import Wizard appears. Follow the steps in the wizard to specify how you want the data arranged on the datasheet.