Hi Shiv,
Excel can only read ASCII text files, it usually can't read binary files of an arbitrary nature. You can convert your data into a text file during acquisition, so that the text file is created from the start, or you can convert your data as an entire file during post-processing.
To convert a binary number to a string, use "Convert Number to Decimal String.VI" This string can then be written to a file. If you de-limit the values with tabs, then excel should be able to read it quite easily. This conversion takes time, so you may want to do this during post-processing.
Another approach would be to port the data directly to Matlab or Excel using either the Matlab script node, or the Report Generation Toolkit for Microsoft Office.