Analysis And Design Of Walking-beam Heating Furnace Monitoring System Based On PLC

In the control process of the steel production, the control of dynamic characteristic of one heating furnace temperature is common, which owns some characteristics as follows.(1) The rising and falling of furnace temperature possess serious asymmetry, including the gain asymmetry and the time lag asymmetry.(2) Volume lags. For general industrial furnace temperature control system, it has larger volume lag and belongs to pure hysteretic characteristic.(3) In the range of temperature control of the heating furnace, the gain and volume lag time of the controlled object are variable parameters, which are associated with the working temperature and load change. For an industrial heating furnace, its dynamic characteristic approximates linear so that the furnace temperature could be controlled well by the conventional PID controller in small scale of the working point. However, when the given values are changed in large-scale or the disturbance of external environment(including condition) is grave seriously, the parameters of PID are revised in time; otherwise the dynamic characteristic of temperature variation would deteriorate. With the development of modern industrial technology, not only the temperature control performance requirements of an industrial furnace are higher and higher, but also the advanced control strategies are required eagerly. In addition, the temperature control system of a heating furnace is significant extremely in equipment automation control process. However, the heating furnace possesses some characteristics, such as nonlinear, time-varying, large lag and heavy distributed parameters so that the furnace temperature of heating furnace is more difficult to control.In this paper, the structure, procedures and control requirements of the walking-beam reheating furnace are introduced, summarizing the research status of walking-beam heating furnace on controlling process, analyzing the temperature prediction control system of walking-beam heating furnace detailedly. Finally, aim at the existing problems, the author has been made some reserches as follows:Firstly, in view of the furnace temperature control process of walking-beam heating furnace exist the characteristic of lag obviously, the relevant theory of PLC process control is proposed.Secondly, compared to the conventionl PID control in the temperature control of walking-beam heating furnace, a novel design schemes is proposed to enhance temperature control system of stepping heating furnace.Thirdly, via learning the control system of the SIMATIC S7-300 PLC systematically, the author has grasped the usages of functional models of advanced processing control in PLC and understanded it deeply and applied skillfully. Meanwhile, the author also studied the procedures about PLC how to establish engineering projects. After that, based on PLC, the hardware and software of heating furnace temperature control system are degisned.The experiment result shows tht the furnace temperature could follow the given value and reach the stedy state based on programmable logic controller system. It is a basic to optimize the heating furnace temperature in the future. By the research in this paper, the design scheme may provide some references for the intelligent control of walking-beam heating furnace.