Research And Development Of Some Issues On The Reliability Of Industrial Controller

As the core component of industrial control system, industrial controller plays an important role in the control system's stability, reliability and safety. The unexpected equipment failure caused by the hardware random failure and system failure of industrial controller and its misoperation during the maintenance will cause serious accidents in the industrial plants. In the case of high temperature, high pressure, inflammable and explosive situations, such accidents will result in serious personal injuries and property damages. How to effectively improve the reliability of industrial controller has become the key issue of the design of industrial control system.The industrial controller's basic architecture, functional and performance requirements are analyzed. Based on the theory of reliability engineering, the controller's hardware reliability and the software reliability are also discussed. This paper focused on how to effectively improve the reliability of industrial controller by the design and implementation of its software mechanisms.A Markov model of hot standby redundant industrial controller is established for reliability analysis. Theoretical analysis shows that the hot standby redundancy can effectively improve the reliability of industrial controllers. And if the repair rate is high enough, the higher the fault diagnosis coverage, the longer mean time to failure (MTTF).For how to effectively achieve hot standby redundancy, a complete software mechanism were designed, with a strict cycle synchronization, initial redundancy, real-time redundancy and fault type based redundancy switching function.For how to effectively carry out fault diagnosis, software mechanisms were designed to enhance the hardware fault diagnosis coverage. A failure record unit was also designed to record the failure events.For online maintenance, the ability of configuration online download and the ability of online upgrade were designed. To meet the requirements of configuration online download, a special technology was designed for multi-tasking industrial controller. A reliable firmware online update mechanism was also designed.Finally, the industrial controller prototype based on the hardware platform of ECS-700 system controller was tested and verified. The results showed that the hot standby redundancy, fault diagnosis functions, and the online maintenance functions can achieve the desired design (?)l. so as to enhance the reliability of industrial controller.