Hello,
It appears you have two devices, one is displayed on a graph and the other is displayed and written to a file. The data acquire loop reads 1000 scans ( 8 * 1000) each time around. Assuming the displayed data is correct, the problem lies within the National Instruments Write To Measurement File Express VI or with the Excel TDMS import tool, both of which are National Instruments products. For help, it is best if you reach out to them for assistance. One thing you could try is writing to CSV instead of TDMS.
best regards,
John
