In a competitive environment, systems design should be agile to accomplish business goal. However, there are often significant problems with systems design that is manifested in the fact that there are no current techniques to apply rigorous mathematics to semantic conveyance in the design framework. As a promising solution, this paper introduces situation theory (ST) and provides an application of ST for information flow in manufacturing systems design (IDEF0). The described work in this paper addresses the procedure of creation of IAST Model (Inf-Act On in Situation Theory) which is the first application of ST in engineering fields. Finally, we show that IAST Model is very helpful for effective information capturing in systems by comparison existing methodology with developed methodology as a practical application of ST.