This paper introduces a new modeling technique that incorporates the information of assembly route cards for modeling the assembly process of complex products. The model enables computerized control over the assembly system, and control over the automation itself. The model has a static part and a dynamic part: The static part of the assembly model integrates both a bill of materials (BOM) tree, and a precedence diagram of the necessary assembly tasks. The dynamic part of the model uses a dynamic Petri net formed around the static assembly model, and ensures that each sub-assembly starts its assembly only after all of its necessary components, tools, and resources are secured and ready. The model can also describe the inputs and outputs of the automatic assembly, along with the Boolean logic with clear distinctions between causes and effects. The model can be translated automatically to ladder diagram and implemented using a Programmable Logic Controller (PLC).