logging data in lab view for diagnostics

[Godson]

I'm able to log lab view acquired data in an excel file using the 'Write to measurement' block. However I also require a specific data logging methodolgy where only the last few minutes ( about 2 to 4 minutes) of data of the program being run are stored in an excel file or in some format even if inside lab view before being stopped. This is to serve as a sort of diagnostic so that if a failure occurs in the hardware being tested, the pattern of data obtained in the supposed event of a failure could help in easy identification of the issue. Please help.

[Dennis_Knutson]

I don't understand what you need help with. You say you are logging data right now but then you ask how to log data. Doesn't your present file contain the entire run where the last couple of minutes is just a subset?

[Godson]

What you're saying is right. But my requirement warrants not only being able to save when I want to with the 'write to measurement' block, but an autosave feature that is continuously recording data and when the program is stopped, only the last few minutes of data should be saved. The 'write to measurement' block doesn't have a timing feature to save my required period. It just starts saving when the program starts or if actuated by a button using a case structure. Hope you understand my problem. Looking for a reply.