data analysing graphs from excel

Question

i have a question at excel. if you can help me??

i need to do data analysing graphs from excel, and they look more or the less the same like this one. and i want to separate them to steps automatically with equation or vba. of course the date always changes but the graph is in the same shape (stages) always.

1. heating until the curve
2. temp the same more or less (from the end of stage 1). called same temp 1.
3. first cooling (with linear equation automatically)
4. same temp 2.
5. second cooling (with linear equation automatically)
6. same temp 3

danieltakeshi told me: I think you could divide it with Piecewise and plotting it, making sure your function is contiguous. You could also have some help on Math. And please read: Why is “Can someone help me?” not an actual question? – danieltakeshi 56 mins ago