there is only filter for lvm files, you can switch to see all files and select the txt file too.
there is a problem when opening the file ... when I choose the file and run the program the menu come automatically and I can't stop the program ... I didn't understand what you mean by lvm filter ? ... and how can I plot the variation of energyy in terms of time for each signal since by project is studying the muscle fatigue and this can be known when the energy is getting increased with time
if you doubleclick on Read From Measurement File, you can uncheck "Ask user to choose file", so VI will use filename you wrote to the top of this window.
By the lvm filter I meant the setting in file dialog when VI asks you for selecting the file. It is the small select list on the right bottom side. I attach also the screenshot.
You can show she signal in time domain using the VI I modified from previous one. About energy values -- you can connect these values to Waveform Graph to see it. Otherwise I probably do not understand exactly what trend you want to show and how. I can help you how to implement it but you have to have clear requirement otherwise I can only guess what you are trying to do.