The difference between DCS and SCADA
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Experts: What is the biggest difference between DCS and SCADA? Or do they each have their own characteristics, and in which areas are they used? Can DCS be used for the oil and gas extraction and on-site processing systems in oil and gas fields?
SCADA System The SCADA (Supervisory Control And Data Acquisition) system is a system for data acquisition and monitoring control. The SCADA system is a computer-based DCS and power automation monitoring system ； It has a wide range of applications, and can be used in areas such as power, metallurgy, petroleum, and chemicals for data acquisition, monitoring and control, as well as process control. In power systems, SCADA systems are the most widely used, and their technology is the most mature. It plays an important role in remote control systems; it enables the monitoring and control of operational equipment on-site, allowing for functions such as data collection, device control, measurement, parameter adjustment, and various signal alarms – what are known as the \"four remote controls\" functions. RTU (Remote Terminal Unit) and FTU (Feeder Terminal Unit) are important components of this system. They play a significant role in the construction of integrated automation systems for substations today.
Overview of SCADA Systems
I. Overview of SCADA Systems
A SCADA system is a computer-based automation system for controlling and scheduling production processes. It can monitor and control the equipment in operation on-site, enabling functions such as data collection, device control, measurement, parameter adjustment, and various signal alarms. Due to the different requirements for SCADA in various application fields, the development of SCADA systems in these fields also varies. In power systems, SCADA systems are the most widely used, and their technology is the most mature. As one of the most important subsystems of an Energy Management System (EMS), it offers advantages such as complete information, improved efficiency, accurate monitoring of the system’s operating status, faster decision-making, and the ability to quickly diagnose system failures; it has now become an indispensable tool for power dispatching. It plays an irreplaceable role in improving the reliability, safety, and economic efficiency of power grid operation, reducing the workload on dispatchers, achieving automation and modernization of power dispatching, and enhancing the efficiency and quality of dispatching. SCADA has been used in railway electrification remote control systems for some time now, and it has played a significant role in ensuring a safe and reliable power supply for electrified railways as well as in improving the level of management in railway transportation operations. In the development of SCADA systems for railway electrification, advances in computing technology have led to the emergence of different products in various periods. Meanwhile, China has also imported a large number of SCADA products and equipment from abroad, all of which have contributed to the advancement of railway electrification remote control systems toward higher standards. II. Development History of SCADA Systems SCADA (Supervisory Control and Data Acquisition) systems are systems for data acquisition and supervision and control. Since its inception, the SCADA system has been closely linked to the development of computer technology. The SCADA system has gone through three generations since its inception. The first generation consisted of SCADA systems based on dedicated computers and operating systems, such as the SD176 system developed by the Electric Power Automation Research Institute for the North China power grid, and the H-80M system designed by Hitachi in Japan for China’s railway electrification remote control systems. This phase spans from the time computers were applied to SCADA systems until the 1970s. The second generation were SCADA systems based on general-purpose computers in the 1980s; in this generation, other computers such as VAX and various general-purpose workstations were widely used, with the operating systems typically being general-purpose UNIX systems. At this stage, in the automation of power grid dispatching, the SCADA system is combined with economic operation analysis, automatic generation control (AGC), and network analysis to form the EMS system (Energy Management System). The common feature of first-generation and second-generation SCADA systems is that they are based on centralized computer systems, and the lack of openness in these systems makes system maintenance, upgrading, and integration with other networks very difficult. The EMS/SCADA systems of the 1990s, which followed the principle of openness and were capable of large-scale networking based on distributed computer networks and relational database technologies, are known as the third generation. This phase was the period of fastest development for SCADA/EMS systems in our country, with various state-of-the-art computer technologies being integrated into these systems. This period was also when China made the largest investments in power system automation and grid construction; the plan to invest 270 billion yuan over the next three years to upgrade urban and rural grids illustrates the level of emphasis placed on power system automation and grid development. The prerequisites for the fourth-generation SCADA/EMS systems are already in place or will be soon, and they are expected to emerge at the beginning of the 21st century. The main features of this system are the use of Internet technology, object-oriented technology, neural network technology, and JAVA technology, etc., to further enhance the integration of SCADA/EMS systems with other systems, in order to meet the requirements of safe and economical operation as well as commercial operations. Breakthrough progress has been made in the application technology of SCADA systems in the remote control systems of electrified railways, and their use has also seen rapid development. Due to the different characteristics of electrified railways and power systems, the development path of SCADA systems is not entirely the same as that of power systems. Among the mature products for the telecontrol systems of electrified railways are the HY200 microcomputer-based telecontrol system developed by our institute, as well as the DWY microcomputer-based telecontrol system developed by Southwest Jiaotong University. These systems are reliable in performance and highly functional; they play an important role in ensuring the safety of power supply for electrified railways and improving the quality of that power supply. They have made a significant contribution to the use of SCADA systems in railway electrification. III. Outlook for the Development of SCADA Systems SCADA systems are constantly being improved and developed, with technological progress never ceasing. Today, with the increasing demand for SCADA systems in power systems and railway electrification systems, as well as the development of computer technology, new requirements have arisen for such systems. Generally speaking, these requirements include the following: 1. Extensive integration of SCADA/EMS systems with other systems. SCADA systems serve as real-time data sources for the automation of power systems, providing a large amount of real-time data to EMS systems. At the same time, real-time grid data is required in systems such as simulation training systems and MIS systems; without this real-time grid data, all other systems become useless. Therefore, over the past decade, how SCADA systems can be connected to other non-real-time systems has become an important topic in SCADA research ； Currently, the SCADA system has successfully achieved connectivity with the DTS (Dispatcher Simulation Training System) and the enterprise MIS system. The integration of SCADA systems with electric energy metering systems, geographic information systems, water dispatch automation systems, production dispatch automation systems, and office automation systems represents a development trend for SCADA systems. 2. Comprehensive Automation of Substations By using RTUs and microcomputer-based protection devices as the core, it integrates the control, signaling, measurement, and metering circuits of substations into a computer system, replacing traditional control and protection panels. This approach helps reduce the space required by substations and the investment in equipment, while improving the reliability of the secondary systems. The comprehensive automation of substations has become a topic of research in relevant fields; companies in China such as Dongfang Electronics have already introduced corresponding products, but it is still in the research stage regarding railway electrification. 3. Research and application of new technologies such as expert systems, fuzzy decision-making, and neural networks
Overview of SCADA Systems
I. Overview of SCADA Systems
A SCADA system is a computer-based automation system for controlling and scheduling production processes. It can monitor and control the equipment in operation on-site, enabling functions such as data collection, device control, measurement, parameter adjustment, and various signal alarms. Due to the different requirements for SCADA in various application fields, the development of SCADA systems in these fields also varies. In power systems, SCADA systems are the most widely used, and their technology is the most mature. As one of the most important subsystems of an Energy Management System (EMS), it offers advantages such as complete information, improved efficiency, accurate monitoring of the system’s operating status, faster decision-making, and the ability to quickly diagnose system failures; it has now become an indispensable tool for power dispatching. It plays an irreplaceable role in improving the reliability, safety, and economic efficiency of power grid operation, reducing the workload on dispatchers, achieving automation and modernization of power dispatching, and enhancing the efficiency and quality of dispatching. SCADA has been used in railway electrification remote control systems for some time now, and it has played a significant role in ensuring a safe and reliable power supply for electrified railways as well as in improving the level of management in railway transportation operations. In the development of SCADA systems for railway electrification, advances in computing technology have led to the emergence of different products in various periods. Meanwhile, China has also imported a large number of SCADA products and equipment from abroad, all of which have contributed to the advancement of railway electrification remote control systems toward higher standards. II. Development History of SCADA Systems SCADA (Supervisory Control and Data Acquisition) systems are systems for data acquisition and supervision and control. Since its inception, the SCADA system has been closely linked to the development of computer technology. The SCADA system has gone through three generations since its inception. The first generation consisted of SCADA systems based on dedicated computers and operating systems, such as the SD176 system developed by the Electric Power Automation Research Institute for the North China power grid, and the H-80M system designed by Hitachi in Japan for China’s railway electrification remote control systems. This phase spans from the time computers were applied to SCADA systems until the 1970s. The second generation were SCADA systems based on general-purpose computers in the 1980s; in this generation, other computers such as VAX and various general-purpose workstations were widely used, with the operating systems typically being general-purpose UNIX systems. At this stage, in the automation of power grid dispatching, the SCADA system is combined with economic operation analysis, automatic generation control (AGC), and network analysis to form the EMS system (Energy Management System). The common feature of first-generation and second-generation SCADA systems is that they are based on centralized computer systems, and the lack of openness in these systems makes system maintenance, upgrading, and integration with other networks very difficult. The EMS/SCADA systems of the 1990s, which followed the principle of openness and were capable of large-scale networking based on distributed computer networks and relational database technologies, are known as the third generation. This phase was the period of fastest development for SCADA/EMS systems in our country, with various state-of-the-art computer technologies being integrated into these systems. This period was also when China made the largest investments in power system automation and grid construction; the plan to invest 270 billion yuan over the next three years to upgrade urban and rural grids illustrates the level of emphasis placed on power system automation and grid development. The prerequisites for the fourth-generation SCADA/EMS systems are already in place or will be soon, and they are expected to emerge at the beginning of the 21st century. The main features of this system are the use of Internet technology, object-oriented technology, neural network technology, and JAVA technology, etc., to further enhance the integration of SCADA/EMS systems with other systems, in order to meet the requirements of safe and economical operation as well as commercial operations. Breakthrough progress has been made in the application technology of SCADA systems in the remote control systems of electrified railways, and their use has also seen rapid development. Due to the different characteristics of electrified railways and power systems, the development path of SCADA systems is not entirely the same as that of power systems. Among the mature products for the telecontrol systems of electrified railways are the HY200 microcomputer-based telecontrol system developed by our institute, as well as the DWY microcomputer-based telecontrol system developed by Southwest Jiaotong University. These systems are reliable in performance and highly functional; they play an important role in ensuring the safety of power supply for electrified railways and improving the quality of that power supply. They have made a significant contribution to the use of SCADA systems in railway electrification. III. Outlook for the Development of SCADA Systems SCADA systems are constantly being improved and developed, with technological progress never ceasing. Today, with the increasing demand for SCADA systems in power systems and railway electrification systems, as well as the development of computer technology, new requirements have arisen for such systems. Generally speaking, these requirements include the following: 1. Extensive integration of SCADA/EMS systems with other systems. SCADA systems serve as real-time data sources for the automation of power systems, providing a large amount of real-time data to EMS systems. At the same time, real-time grid data is required in systems such as simulation training systems and MIS systems; without this real-time grid data, all other systems become useless. Therefore, over the past decade, how SCADA systems can be connected to other non-real-time systems has become an important topic in SCADA research ； Currently, the SCADA system has successfully achieved connectivity with the DTS (Dispatcher Simulation Training System) and the enterprise MIS system. The integration of SCADA systems with electric energy metering systems, geographic information systems, water dispatch automation systems, production dispatch automation systems, and office automation systems represents a development trend for SCADA systems. 2. Comprehensive Automation of Substations By using RTUs and microcomputer-based protection devices as the core, it integrates the control, signaling, measurement, and metering circuits of substations into a computer system, replacing traditional control and protection panels. This approach helps reduce the space required by substations and the investment in equipment, while improving the reliability of the secondary systems. The comprehensive automation of substations has become a topic of research in relevant fields; companies in China such as Dongfang Electronics have already introduced corresponding products, but it is still in the research stage regarding railway electrification. 3. Research and application of new technologies such as expert systems, fuzzy decision-making, and neural networks
I believe SCADA focuses primarily on monitoring process displays, while DCS includes monitoring process displays but places more emphasis on control, especially complex control. The core of SCADA is the upper-level software, whereas DCS refers to the entire control system.
SCADA is generally used for simple data acquisition and monitoring, while DCS can not only acquire and monitor data but also control the variables being monitored.
SCADA is simply a PLC control system in which control functions are distributed. Applications such as pipeline projects, urban water and power supply dispatch systems, and railway train dispatch systems are all implemented using SCADA. Well-known manufacturers include Bristol from Emerson and Yokogawa; in China, companies like AnKong also produce SCADA systems. SCADA focuses on monitoring and places great emphasis on the upper-level software. DCS, on the other hand, also distributes control functions, but these are limited to within a single factory complex. DCS pays equal attention to both control and monitoring functions; thus, each system has its own strengths
DCS is a comprehensive system that covers everything from human-machine interaction to field devices, with an emphasis on control at the field level. SCADA, on the other hand, focuses on information exchange at the higher-level computer systems, and it serves to work in conjunction with the hardware used at the field and control levels
I agree quite a bit with what was said on floor 6: SCADA focuses on data collection and data exchange between humans and machines, with not much control over processes
SCADA is a part of the system, primarily responsible for data collection and monitoring. DCS is a system that includes SCADA, controllers, IO devices, communication devices, and network devices. SCADA+PLC (medium and large scale) + other communication control software can be referred to as a DCS. The above are my personal opinions.