The objective of this paper is to propose a methodology of ladder code generation using state diagram. The
methodologies of ladder code generation were proposed previous related work using petri-nets have complex
structures and are difficult to apply to business practice. So, In this paper, the processes of work and
informations related to input and output of ladder logic are modeled by using Timed FSA method and ladder
code is generated by matching the proposed methodology. The verification of this methodology is conducted to
automobile assembly plant. The application to simulation for verification and validation and the auto generation
will be possible enough after standardization of symbol although the proposed methodology is not
auto-generation of ladder code