Industrial application

Industrial control system is the requirement for high-speed transmission of large data such as images and voice signals, and it also gives birth to the combination of Ethernet and control network, which is popular in the commercial field at present. This networking wave of industrial control system integrates many popular technologies such as embedded technology, multi-standard industrial control network interconnection and wireless technology, thus expanding the development space of industrial control field and bringing new development opportunities.
With the development of computer technology, communication technology and control technology, the traditional control field is undergoing an unprecedented change and begins to develop in the direction of networking.
The structure of control system has developed from CCS (computer centralized control system) to DCS (distributed control system) of the second generation to FCS (field bus control system).

development trends
Computer and network technology are closely related to the development of control system. As early as the middle and late 1950s, computers have been applied to control systems. In the early 1960s, a control system in which analog control was completely replaced by computers appeared, which was called direct digital control (DDC). In the mid-1970s, with the advent of microprocessors, The computer control system has entered a new period of rapid development. In 1975, the world's first set of distributed computer control system based on microprocessor came out. It is called distributed control system (DCS), which is controlled by multiple microprocessors and managed centrally through data communication network.
control system
Since the 1980s, people have used microprocessors and some peripheral circuits to form digital instruments to replace analog instruments. This DDC control method has improved the control accuracy and flexibility of the system, and has a performance-price ratio unmatched by traditional analog instruments in multi-loop sampling and control.
In the middle and late 1980s, with the increasing complexity of industrial systems and the further increase of control loops, a single DDC control system can no longer meet the requirements of on-site production control and management of production work, and the performance-price ratio between small and medium-sized computers and microcomputers has been greatly improved. Therefore, hierarchical control systems with the interaction of small and medium-sized computers and microcomputers have been widely used.
Since the 1990s, with the rapid development of computer network technology, the DCS system has been further developed, and the reliability and maintainability of the system have been improved. In today's industrial control field, DCS still occupies a dominant position, but DCS is not open, its wiring is complex, its cost is high, and the integration of products from different manufacturers is very difficult.
Since the late 1980s, with the development of large-scale integrated circuits, many field devices, such as sensors, actuators and drivers, have become intelligent, and people began to seek to connect the field devices with a unified communication protocol communication interface with a communication cable. The I/O (4 ~ 20 mA/24 VDC) signals are no longer transmitted at the device layer, but digital signals. This is the Fieldbus. Because it solves the problems of the reliability and openness of the network control system, the Fieldbus technology has gradually become the development trend of the computer control system. Since then, some developed industrial countries and multinational industrial companies have launched their own Fieldbus standards and related products, forming a competitive trend.
Industrial control uses control principles and technical means to monitor, adjust and control the industrial process, so as to achieve the goal of automation, high efficiency, safety and reliability of the production process. In modern industrial production, industrial control scheme is a key link, which covers the control requirements of various fields, such as automatic control system, instrumentation, sensors, actuators, etc. This paper will discuss the significance, components and implementation methods of industrial control.
A \ the significance of control principle
The design of industrial control scheme is inseparable from the application of control principle. Control principle is a set of scientific principles and methods used to describe and solve various problems in the control system. By modeling and analyzing the system, it determines the appropriate control algorithm and parameter settings, so that the system can respond to external changes stably and accurately. The application of control principle can improve the quality and efficiency of industrial production process, reduce energy consumption and meet the needs of users to the greatest extent.
II. Elements of Industrial Control Scheme
1\ Automatic control system
Automatic control system is the core part of industrial control scheme, which includes sensors, actuators, controllers and man-machine interfaces. Sensors are used to collect real-time data, such as temperature, pressure and flow. The actuator is used to carry out corresponding actions according to the control signals. The controller is the core of the control system, which can control the process through the functions of calculation, judgment and feedback. The man-machine interface provides a friendly interactive platform for the operators to understand and operate the control system.
2\ Instrument and equipment
Instrumentation equipment is a tool for measuring and displaying process parameters, such as thermometer, pressure gauge, flowmeter, etc. They provide information of process variables to operators and monitor the running state of the process through display instrument, recording instrument and alarm instrument. The accuracy and reliability of instrumentation equipment are very important for the successful implementation of industrial control scheme.
3\ Sensors and actuators
Sensors and actuators are key components in the process of automatic control. Sensors can convert physical quantities into electrical signals and transmit them to the controller. Actuators receive instructions from the controller, produce corresponding actions and change a certain state in the production process. The selection and application of these two will directly affect the effectiveness and stability of industrial control schemes.