Simulink add signals wrong output

Hello,

I'm working with Simulink for my masters thesis since quite a few months now but now I have a problem that I don't understand:

When I add up a few Signals (outputs of Function Blocks or Sources) the output is not the sum of the single Signals. There is some kind of shift of the sum, it matches at some points but interpolates between them. How can I fix that?

I added the Function (sum) that I plottet and the plot. In that part Signal 1, 2 and 4 are 0 so the sum is easy to see.

I also tried the "sum" function block and also a matlab fcn, that adds them up. Same problem with each way.

Thank you.

Best Wishes Sebastian

Answer 1

[Sebastian Eichhorn]

Hey,

my academic supervisor knew the problem and showed me the solution: The variable step time of the simulation has to set to a fix one. Apparentely if the program doesn't find any further code processing the outcome it tends to interpolate quite randomly by increasing the step time and therefore changing the displayed curves.