微机保护中VxWorks系统对SDRAM芯片自检功能的实现

SDRAM Chips under the VxWorks Implementation of Self-check Function

电力系统二次设备中的微机保护装置需要稳定、可靠地运行,要求除出口继电器外装置内任一元器件在发生故障时都不致引起误动或拒动。近年来各保护装置厂家都在逐步采用SDRAM作为程序和数据存储器,但SDRAM芯片本身没有自动检测和纠错功能,而且大容量随机储存器容易受到现场电磁干扰而发生故障。错误的指令会导致程序运行不可预测,错误的数据更会严重威胁系统安全,所以有必要对SDRAM采取必要的检测手段。因此作为保护装置中的关键性元器件,在装置正常运行时对SDRAM芯片的自检就显得特别重要和迫切。本文提出了一种在嵌入式系统正常运行时对SDRAM芯片进行自检的方法,实践证明切实可行,并在我公司的继电保护装置中得到了广泛的应用。

The microcomputer-based relaying protection devices of secondary equipment in power grid system, needs a stable and reliable operation. Except the lockout relay breaks down, the device should not result in operating erroneously or failing whenever any components inside the device get failure. In recent years, the relay protection device manufacturers are gradually using SDRAM for program and data memory, but the SDRAM chip does not have automatic detection and correction functions, and the large-capacity SDRAM is susceptible to electromagnetic interference. Wrong instruction will cause unpredictable result, and wrong data will also be a seriously threat to system security, so it is necessary to have method to monitoring SDRAM. Therefore, as a key component in the relay protection equipment, the self-checking of SDRAM chip during normal operation will be important and urgent. This paper presents a SDRAM chip self-checking method during the embedded system running, this method has been verified in application, and widely used in company equipments.