< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > Hi! I've been working on reducing a controller with block reduction in order to understand it and I have trouble to continue since I've stumbled across something that I haven't seen before. My goal is to find a transfer function basically. The block that I reduced looks like this one : https://postimg.org/image/qqfa54ltf/ My attempt now was to reduce the outer integrator, 1/s, by dividing it into two parallell blocks (a rule that I've followed) and continue with the block reduction. Here is what I got after doing this step. https://postimg.org/image/fkdmoqzpv/ And it is now that I'm lost. I know that I need to reduce the outer loop but I don't know how to do it when we have two summations in row. Anyone that can help?