Implementation of telecontrol protocols in SCADA systems based on FSM

In China power systems began to carry out the international standard protocol-IEC60870-5-101 as the communication protocol for telecontrol, teleprotection, and associated telecommunications in 1998. For the sake of the generalization of IEC60870-5-101 standard and the development of the high quality software, this paper introduces the Finite State Machine (FSM) theory for design of the communication software of the master station in SCADA systems. And this paper also presents a new framework of implementation of FSM according to the OO method. The introduction of this framework can not only make the software more reusable and flexible, but also can improve the maintenance and robustness. With the development of communication software, a more convenient and universal design pattern is introduced.