In information systems, data engines are typically a specialized technology for accessing databases. In 2000, the PineControl Distributed Control Systems research group discovered the potential to leverage database technology to develop supporting software systems for DCS control stations , thus better supporting the implementation of online configuration technology for control systems. To this end, the research group conducted in-depth research on real-time database technology and corresponding data engine technology based on industrial process automation control platforms, launching a new data engine technology with commercial application value. The main feature of this technology is its ability to generate state changes for driving control logic elements based on input and output data, achieving the goal of effectively executing control configuration algorithms. In fact, this data engine technology also sparked the establishment of a cross-platform control configuration standard, which is highly beneficial for promoting the development of DCS technology.
This paper explains the fundamental principles of data engine technology and its role in transforming the performance of traditional DCS control stations. By analyzing its application in DCS control stations, it elucidates how control configuration standards should be established and how the online compilation function of control configuration logic can be implemented. Data engine technology has already been successfully applied in several power plants.
Control logic configuration software is the core technology of DCS. However, the control configuration software configured in current DCS products still suffers from a series of technical problems to varying degrees. First, almost all DCS configuration software is based on the mechanism of converting control logic flowcharts into specific control command sequences, which limits the realization of online modification and cross-platform operation of control logic. Second, the self-diagnostic capability, online monitoring capability, and real-time calculation capability of DCS control configuration also have many problems. The phenomenon of unstable state transitions is also particularly prominent during the redundancy switching of control stations. All these problems are concentrated in the operational mechanism of the command sequence corresponding to the control configuration.
In the research and development of the PineControl distributed control system, researchers proposed a new DCS configuration software environment: PineCAD. Superficially, this configuration software appears similar to traditional DCS configuration software. However, PineCAD's working principle involves mapping the control logic flowchart to a specific real-time database, rather than creating a sequence of computational instructions for a particular DCS control station. More importantly, PineCAD's design philosophy delegates the configuration of control logic to a virtual DCS control station (i.e., a data engine), rather than a traditional DCS control station. This design concept represents a significant shift in DCS technology development. If the data engine can be installed on DCS control stations on different platforms or on devices with computing capabilities such as PLCs and PCs, then PineCAD can integrate the corresponding systems to form a unified DCS, establishing a DCS configuration standard. This will positively impact the upgrading, replacement, and system migration of DCS components, bringing significant application value to DCS users.
A data engine is a technical specification whose working mechanism is similar to that of a car engine. Different car manufacturers have different engines, but these engines must adapt to the technical requirements of the standard gasoline physicochemical structure to generate power during combustion. A data engine is a collection of software that depends on a specific DCS control station's computing instruction environment and is embedded in a specific real-time database. It simulates the computing flow formed by the DCS configuration diagram and drives the calculation process of the entire control station's control element sequence.
In a DCS control station, a special real-time database needs to be installed, where the technical functions of the data engine are set in the relevant attributes of the database. When PineCAD configuration data is generated and downloaded to the real-time database, the state of each control element will change specifically under the action of the corresponding data engine attributes, thereby realizing the control function. We note that the calculation process of this control element is isolated from the calculation command system of the corresponding control station through the data engine; therefore, PineCAD configuration data can be used in different DCS control stations.
The data engine has replaced the traditional calculation processes and methods of DCS control stations. Its main operating mechanisms include the following aspects: management of control element topology calculation processes, execution of control algorithms, online monitoring of control elements, online correction of internal parameters of control elements, online configuration processing, freezing of control element calculations, and management of control element calculation cycles.
Online configuration of control logic in a DCS control station is a highly complex technology, yet it is a crucial requirement in engineering practice. The core issue is ensuring the continuity of control variables before and after configuration modifications. Traditional DCS control station operating mechanisms struggle to guarantee the continuity of all control element states during such modifications, potentially leading to abnormal generator shutdowns. DCS control stations employing data engine technology can effectively address this problem. A key characteristic of data engine technology is that the calculation process for control elements is based on their topological spatial structure, independent of their location in the database or control station memory, and also unrelated to other characteristics of their states (such as state names).
Due to historical and commercial reasons, configuration data between DCS and PLCs from different manufacturers are not directly compatible, which undoubtedly has many negative impacts on investments in industrial control systems. To address this, the International Electrotechnical Commission (IEC) developed the IEC 1131 PLC standard in 1993. The IEC 1131-3 standard specifies five programming languages. After 1998, this standard was changed to IEC 61131. However, this only solves part of the PLC configuration compatibility problem, and the compatibility of PLC configurations remains limited to the similarity of interface forms; DCS, on the other hand, lacks a unified standard configuration format.
Like PLCs, DCS also requires corresponding configuration standards. Such standards can greatly protect the investment of DCS users, ensuring that configuration resources are fully utilized during today's rapidly evolving control station platform technologies and DCS upgrades; different DCS systems can also effectively share configuration resources; and integrated DCS systems can adopt a unified configuration environment, improving the reliability and maintainability of the DCS. Therefore, in today's era of rapid information technology development, the standardization of DCS configuration is both crucial and urgent.
The technical challenges of DCS configuration standards are significantly greater than those of PLCs. Today, people are accustomed to the mixed processing of digital and analog control signals. Besides meeting cross-platform configuration requirements, DCS configuration standards cannot use five different language environments like PLCs. So, what technical methods can facilitate the establishment of DCS configuration standards ? We believe that data engine technology is the most suitable approach. The mechanism of data engine technology can establish a direct data processing mapping between the PineCAD graphical configuration environment and different DCS control station instruction sets. This allows DCS control station manufacturers, configuration software manufacturers, and even DCS users to avoid significant technical investment in promoting DCS configuration standardization.
In addition to possessing the technical foundation of DCS configuration standards, data engine technology can also eliminate the long-standing controversy over whether there are functional differences between DCS control stations and PLCs, making PLCs a viable option for DCS control stations. This has significant value in both DCS technology and business aspects.
The research and application of data engine technology has made significant progress in the past two years. Researchers at Beijing Huaneng Xinrui Control Technology Co., Ltd. have fully utilized the technological advantages of data engines to develop two new DCS systems: PineControl and HNA5000. PineControl passed the technical appraisal of the State Grid Corporation of China in 2002. These two DCS systems use different PLCs as control stations, fully demonstrating the cross-platform operation and integrated DCS construction capabilities of data engines. In such a DCS, the core of all control stations is consistent and does not change due to different controlled objects. The number of components in the control stations is the fewest among similar products, and the hardware assembly is very easy. The PLC equipped with this data engine achieves the advanced level of current international DCS products and technologies in terms of computing, management, and real-time security performance. As a PLC platform, the environmental adaptability and reliability of this DCS control station exceed those of traditional DCS systems.
To date, the PineControl distributed control system has been operating in four coal-fired generator sets and two power plant auxiliary systems, and the HNA5000 will also be applied in generator sets. These DCS application projects include the DCS system transformation of 350MW imported generator sets[3], the DCS project of newly built imported domestic circulating fluidized bed boiler heating generator sets, the transformation of the boiler ash removal and slag removal control system of large generator sets, and the DCS transformation of the electrical control system of generator sets. After more than three years of operation practice, the design concept and implementation principle of data engine technology have been tested by various operating conditions of these generator sets, achieving a good application effect of first-class control quality and safe, reliable and fault-free operation, and has been highly praised by DCS users.
In summary, the data engine is a new technology in DCS that injects new vitality into the future technological development of DCS, promotes the standardization of the DCS system, truly realizes the online configuration function of DCS control stations, and completely eliminates the differences between DCS control stations and PLCs. In the future, with the rapid development of information technology, data engine technology will play an increasingly important role.
