A Study On Improvement Of The Automatic Control System Of Furnaces For Smelting Iron In Yu Gang Company

For a designer of industrial control system,the reliability is always the first priority.Usually,two ways can be used to improve the reliability of the control system: intolerance of malfunction and allowance of malfunction.The first way is zero tolerance to the failure of components,it aims to construct a “perfect” system without any fault.While the allowance of malfunction firstly supposes that faults exist,then utilizes the extra worked assemblies of the system to replace those damaged,thus the setup of extra assemblies are important,the double-machines fault-allowance control system is an example.This thesis detailed discusses both aspects of software structure and software designing,and conducts the reliability analysis of the system based on double-machines reliability model.Both theoretical and empirical results show that the double-machines system outperforms the single-machine system.This study focuses on the solving the problem of computer-automatic-control system of furnaces for smelting iron in Yu Gang Company,and presents the solutions and further improvements to the existing problems,respectively.By these improvements,the furnaces for smelting iron can operate stably,and the effect of PLC control system on the production procedure is significantly reduced,and moreover,those serious accidents are prevented.There are two iron-smelting blast furnaces in Yugang Company of Jiugang Group.The original control mode of the blast furnace is single-net and single-CPU.For large-scale control system,single-net and single-CPU control mode can not meet the actual requirements of the practical production sites.New electrical equipments are needed to add and control through the constant development of automatic control system of computer and according to the requirements of the production process in the producing operation.The current CPU capacity,network systems and control methods can not meet the controlling requirements of the production process.Therefore,there are the need for technological transformation of the automatic control system to increase dual-network,dual power and dual-CPU control in each blast furnace,to re-design and adjust the PLC program and configuration,to optimize the program,to combine the number of controlling program points,to reduce the operational load of CPU,and to transform the power supply system.Through the additional settings of a series of main control modules and optimal adjustment of control procedures listed above,dual-network and dual CPU control system are put to use to ensure the system and network to operate with security and stability.After the transformation,the network structure is the RIO way with dual-computer and dual-cable connection,that is,two CPUs and other functional modules are connected by two network communicating cables with remote IO,including Ethernet communication,also by means of double-switch and dual network cable communicating with the lower control system.The practices verify that the improved control system works very well.