Abstract: The communication scheme of SIMATIC WinCC and S7－200 in engineering has been presented. Based on PPI communication protocol, a host computer network constituted of PC Acess and OPC Sever communicates with S7－200, which leads to the synchronous monitoring for WinCC and S7－200. Fuzzy PID control has been used for the system control which realizes fast and stable constant temperature heating. And through the high speed output, the control of stepping motor has been achieved by PWM mode.

Key words: WinCC, PC Acess, S7－200 PLC, fuzzy PID control