Research And Development Of Real-time Database For Configuration Software Of New DCS

DCS is widely used in industrial process control, and the control system is asked to quickly reflect the current status of the process. The data acquisition and output control are temporarily valid. If alarm occurs or some device failure happens, the monitor system should recognize that immediately. So the configuration software has a harsh deadline for critical tasks. The traditional databases ignore the real-time requirements for transaction processing. It can not be applicable to time-critical applications. So the special real-time database is introduced to solve the problems.This thesis was proposed under the background of industrial control configuration software. First, it introduces the theoretic and design goals of the real-time database system (RTDBS), And then, it illustrates the real-time database system functions in details based on the independent innovation new DCS hardware platform and the former configuration software framework. In-depth understanding of process control requirements, the thesis brings up a new real-time data model for configuration software. It introduces the schematic design of the RTDBS functions. Such as, configuration functions, data acquisition and output control, data processing, alarm processing, and the support to other components and the third-party applications. It also talks about the extended functions of RTDBS.A main memory database is used to achieve the base implementation of the RTDBS. Building the entire database in the main memory can meet the maximum real-time requirements of the applications. But this scheme brought new problems. It is necessary to redesign the data storage mode, search algorithm, transaction processing and concurrency control protocols according to the memory access characteristics and the configuration software features. On the study of various transaction processing methods and concurrency control protocols, a strategy based on multiple priority queues and database level lock protocol was raised to meet the real-time requirements of the configuration software database. This thesis takes a separate chapter to introduce the key technologies to implement the RTDBS kernel.The interfaces are the communication center to adapt the RTDBS with the upper layer applications and the process control layer. This thesis shows how the interfaces are designed and implemented. The convertion from real-time data to historical data is essential for configuration software. The system uses SQL Server 2000 as the background historical data management center. This thesis gives a detailed explanation to historical database convertion. Real-time database system uses COM technology and multi-threaded design to ensure the real-time database system with flexible scalability and efficient data processing capabilities.At last, a benchmark of basic operations was taken to test if the RTDBS can perform better than traditional database. The result shows that the RTDBS has a clear advantage on SQL Server 2000; it also proves that the design of the RTDBS is workable.The real-time database system has been integrated into the configuration software now. It is running stability and can meet the current requirements for real-time.