I see your point but this is not what I need. I measure T1 and T2 and also voltage/time. So here voltage/time is linear. I need to take the slope of the voltage/time. For this reason I need to seperatre this triangle data from T1 and T2 simultaneously voltage/time. Thus what you offer is not related to this part. Thanks for your effort. What can be done to sperate data?
Here is a simple approach to finding the triangles. It breaks the data into short segments (Length) and calculates the slope of each segment. For the demo I just plotted the slopes. The trade off with length is that longer lengths gives smoother data but more uncertainty about where the slope actually changes. With a little bit of math you can convert slope array indexes into indexes in the data array to get the triangle data.
The way your data is formatted into the .xlsx file, you have lost all of the meaningful timing data.