Optimization for control system of heating furnace instrument based on PLC

YANG Lihua

(Department of mechanical engineering, Sichuan Mechanical and electrical Institute of
Vocation and Technology, Panzhihua 617000, China)

Abstract: Aiming at the problems of the stability of heating,furnace automatic control instruments and realtime monitoring. The problems of heating furnace temperature control system, cascade control system, temperature & pressure setting of furnace and safety interlock system were discussed. Some accidents were analyzed , such as the entrance of highpressure blower was reduced, heating furnace stopped because of low air pressure and the waterlevel increased due to unreliable water level treasuring which results in the waterlevel of heating furnace increases. The high pressure blower PI automatic regulation system and PLC realtime monitoring technology were summarized. Some suggestions were given on how to improve PI controller, PLC control program and methods for the abnormal state of equipments in realtime monitoring. The results of study show that the two highpressure blower inlet regulator are flexible, convenient and stable. No interference problems. The monitoring for the bottom water level of heating furnace and the accident rate are reduced greatly. The automatic control system of heating furnace after being optimized has the characteristics of stability, high precision and low failure rate, which reaches the standards of the design.

Key words: heating furnace; PLC; design; safety chain; optimize