This paper described a PLC (Programmable Logic Controller) program model and its implementation, based on the IEC 61131-3 Standard. The Model was built using the State Machine Theory and Petri nets, the transformation into IEC 61131-3 Programming language was made in the application part using a FMS (Flexible Manufacturing system) as a case of study, which has six work stations controlled by six different PLC's. For the Model implementation, Rockwell Automation software was used, making functionality test on each work station whit the aid of a SCADA system.