You need to learn about data dependency!
In your VI you are performing three actions simultaneously:
- Reading from an instrument and collecting data and then writing it to a text file in tab-delimited format, and then reading that file, but not doing anything with it.
- Opening an Excel workbook and then a worksheet, and then closing the reference to the workbook.
- Opening the Excel application and then closing it the reference to it.
Why do you need to open/close Excel if you're already writing the data to a text file in tab-delimited format? Excel can read this directly.
I would strongly suggest going through the LabVIEW tutorials that discuss data dependency and how to code in LabVIEW.