故障树分析在水产养殖监控系统可靠性设计中的应用

Application of fault tree analysis(FTA) in reliability design of monitoring and controlling system for aquatic products breeding

简单介绍了水产工厂化养殖计算机监控系统的组成及工作原理 ,该系统是一个由工业控制计算机作为上位计算机、单片机控制系统作为下位计算机的典型计算机集散控制系统。为保证系统工作的安全可靠性 ,增强系统的实用性 ,以鱼类因水体溶解含氧量严重超限而死亡作为顶事件为例 ,进行了故障树分析 ,得到了提高系统可靠性的基本思路 :即利用单片机和上位机的软硬件冗余资源来构成容错系统 ,通过改变故障树的拓扑结构来减少低阶最小割集数 ,以降低顶事件发生的概率。通过对故障树的评价 ,提出了提高系统可靠性的基本方法 ,主要有 :减少人为操作失误 ;单片机系统硬件进行可靠性设计 ;单片机和上位机的控制系统软件中增加和完善纠错程序和故障诊断程序。理论分析和试验结果表明 ,采用文中所述方法能有效消除系统中由于部分硬件故障、软件缺陷、人为失误、以及受外界电磁干扰等不良因素所带来的不利影响 ,保证水产养殖的正常进行。

The paper briefly introduces the constitution and operation of a computer based monitoring and controlling system for aquatic products breeding. This system is a typical computer based distributed control system that is composed of industrial control computer as upper level computer and single chip microcomputer control system as lower level computer. On the basis of the fault tree analysis, the essential idea for raising operation reliability of the system was produced to assure security and reliability of system and build up practicability of the system. The essential idea was using software and hardware redundant resources of single chip microcomputer and industrial control computer to constitute error tolerating system, reforming the topology of fault tree to reduce the number of low order minim cut sets, so as to lower the probability of the top event. By evaluating fault tree, the essential measures were also introduced mainly as follows: reducing the man made operating misplay; making reliability design of single chip microcomputer system and improving error correction program and fault diagnosis program in control software of single chip microcomputer control system and industrial control computer. Theoretical analysis and experimental results indicate that ways presented in this paper can effectively remove negative effects induced by part of hardware faults, software defaults, man made misplay and outer electromagnetic disturbance, etc, in this system, so as to ensure the performance of aquatic products breeding.