The Time History file format is one of the 2 line formats that the ACS-SASSI user interfaces can read and display. ( Spec is the other ). This file format will have many extensions (*.TH, *.ACC, …) but the format for the file is always the same for all the extensions
The first line of the file is the sample rate for the time history. the rest of the lines in the file are the values of the time history with one value per line.