Research And Application On Real-time Database Of Configuration Software

Monitoring configuration software is the professional software for supervisory control and data acquisition of industrial process control system. Real-time database as the core part of configuration software is the data exchange center. It completes data acquisition and judgment, operation and processing, the alarm processing, data transfer and other functions. In the field of industrial automation, real-time database provides the data support for advanced control software for on-line optimization, model identification, multivariable predictive control, soft sensor and so on. Therefore, how to ensure the data timely is the main content of real-time database.System structure of real-time database is designed, the structure and function of each subsystem is described in detail. The real-time database system is divided into five parts in this paper, that is, the initial subsystem, data interface subsystem, operation management subsystem, data management subsystem and application interface subsystem. This five parts interconnected, complete data acquisition, processing, storage, and other functions. In order to ensure the data timely, real-time database is permanent in memory. According to the different attributes of variable, the data objects divided into analog, switch signal and character type signal. Real-time database kernel mainly constitutes by the analog arrays, switch arrays and character type arrays. The three memory arrays storage variable properties, such as variable name, data type, the original value of data, the process value of data and so on.The initial subsystem puts I/O variables which from users into the memory arrays, and provides add, delete, modify etc editing functions of variable table for users. Data interface subsystem collects data by OPC, DDE, I/O communication application programming, I/O driver way etc. In the process of data collection, a data status is given to judge whether the data be collected or not be collected. Data is stored in the memory arrays according to variable name. Operation management subsystem timing takes the real-time data to relational database to store, which prevents the data lost during operation. The system loads real-time data which was stored in relational database previously when restarts to enhance system availability. Data management subsystem can accomplish alarm processing and historical data processing function. In the alarm processing, alarm condition, alarm type and alarm priority is given, the alarm processing flow is designed, storage formats of alarm information for different data objects is defined. In the historical data processing, many data were collected when the save time is coming, because the scan cycle is short than the save cycle. According to this problem, the methods of data saved are given respectively for analog, switch signal and character type signal. Application interface subsystem provides the interface functions which are used to call real-time data, historical data and alarm data from real-time database for users. Some functions is designed, such as read data function, write data function, obtain data attributes function, read the alarm data function, etc.The main functions of real-time database system are realized by C#. Such as the loading and editing of variable table, data acquisition, data management, data storage etc functions is realized by C#. Collect data by OPC interface mode. Choose Access relational database in storage of data from real-time database. Real-time database system is released by the form of the dynamic link library.Finally, take a cement project for example, choose the AC800M of ABB as the lower control system, develop graphical by C# as the graphical user interface, call for the real-time database system, and realize system application.