摘要
PLC作为基于微处理器的通用工业控制装置,能够执行各种形式和级别的复杂控制任务,已经成为当代工业自动化的主要支柱之一。大量的工程实践表明,PLC外部的输入、输出元件,如限位开关、电磁阀、接触器等的故障率要远远高于PLC本身的故障率^([1])。而这些原件出现故障后,PLC一般不能自行诊断出来,很有可能造成故障扩大,直至强电保护装置动作后停机,容易造成设备及人身事故。而在编程设计时充分引入系统安全理念,充分考虑到系统自身的逻辑关系,从逻辑错误、超时检测和互锁设计等方式入手,预设一定的故障检测与诊断功能,则可以大幅避免上述问题。
PLC,as a general industrial control unit based on microprocessor,can perform a variety of forms and levels of complicated control task.It has become one of the mainstay of the contemporary industrial automation.A large number of engineering practice indicates that PLC external input/ output components,such as limit switches,solenoid valve,contactor have the higher rate of failure than PLC itself.However,PLC can not diagnose those failure,the failure is likely to be expanded,until the high voltage protective device trigger,it is easy to cause equipment and personal accident.So the system safety concept should be fully introduced when programming design,the system＇s own logic relationship,such as logical error,timeout detection,interlock design.The design of fault detection and diagnosis function can sharply avoid the above problems.
出处
《中国钼业》
2016年第6期58-60,共3页
China Molybdenum Industry
关键词
PLC安全
逻辑错误
超时检测
互锁设计
PLC security
logical error
timeout detection
interlock design
