The programmable controller takes the central processing unit as its operation core and occupies an important position in the current field of electrical automation. The field of automatic control and the advanced technology of computer cross-integration, in the field of industrial control has formed a programmable controller.
Analyzing and exploring the principle and application technology of programmable controller can better promote the development of programmable controller and improve the level of industrial control automation in China.
In this paper, the principle and application of programmable controller are discussed to a certain extent. Programmable controller is the product of the integration of automation field and computer field. It gradually replaces the traditional equipment with its own characteristics in performance and function, and becomes an important part of industrial automation control nowadays. Programmable controller first appeared in the United States, is an advanced device based on micro-computer technology, is one of the results of computer technology in the field of automation.
[1] Compared with the traditional equipment, the programmable controller has many advantages, such as high reliability, low energy consumption, strong ability to resist external interference and so on. Therefore, it has broad application prospects and is widely used in the current industrial control field. The components of the programmable controller are similar to those of the computer. Its structure is shown in Figure 1. CPU occupies an important position in the control core of the programmable controller. Its function is to collect and store the program and data needed in the system, and to monitor the running status of the components in the system in real time. It is responsible for diagnosing the errors of the users in the programming process, so as to ensure the smooth operation of the whole system. Power supply for the normal and smooth operation of the whole system. Memory can be divided into RAM and ROM. RAM is used to store user programs, while ROM is used to store system programs. Fourth, the input and output interface. The last component is auxiliary relay. A single programmable controller is usually equipped with multiple auxiliary relays to ensure normal operation. 。 These components coordinate and cooperate with each other to promote the smooth operation of the programmable controller.
The essence of programmable controllers is a computer system that controls programs and can be used in industrial environments. It operates in a repetitive manner under the control of the host program. Its working principle follows the following three steps (Figure 2). In the process of sampling the input information, the CPU first scans the object and transfers the scanned data results to the register. [2] The data results include the operation parameters and efficiency of the equipment, the current state and temperature and other indicators. After the input information sampling process is completed, it begins to enter the process of program execution. The CPU executes in sequence according to the program instructions issued by the user program; the CPU reads the required execution conditions directly from the programmable elements and input status registers, and carries out corresponding arithmetic and logical operations on the data according to the arrangement set by the program, and finally delivers the data results of the operations. After executing all the instructions received, the CPU will refresh the data information in the program, repeat the above two operation links, and complete the input, output and operation of the new data. The operation process of the above three links combined with the system control of the programmable controller is called a cycle operation. [3] The continuous repetition of the cycle constitutes the working principle and process of the programmable controller. Generally speaking, the shorter the running time of a programmable controller is, the more times it can run in the same time.
This is very important to improve the control and supervision ability of industrial environment. The programmable controller improves and improves the traditional computer application program, integrates computer technology and industrial control technology, and forms a new computer system. In the actual industrial control process, the programmable controller forms a interconnected system with the equipment through the interface.
The equipment inputs its own running data into the programmable controller. The programmable controller stores data information, performs arithmetic and logic operations and outputs. The data output by the programmable controller is the basis for optimizing the operation state of industrial equipment control. The application of programmable controller in industrial control has played an important role in improving the industrial operation environment. It successfully separates man from machine, improves the working environment of workers, improves the production quality and productivity of enterprises, and promotes the improvement of industrial control level. Compared with the traditional equipment, the programmable controller has greater advantages, so it is more and more widely used in the current industrial control. The rapid development of information technology has brought opportunities for the wide application of programmable controller. First of all, the technological achievements of computers will be applied to programmable controllers. The programmable controller will be greatly improved in terms of storage capacity and operation speed, thermostatic element and its adaptability to various industrial environments will be strengthened. Secondly, with the development of computer networks, programmable controllers and other types of industrial control computer systems are intertwined and integrated, and programmable controllers will develop towards large-scale control systems.
With the emergence of large-scale control systems, programmable controllers will no longer be confined to the industrial field, but can be widely used in more fields to promote the improvement of automation level in various fields. Finally, the product scale of the programmable controller will develop towards the direction of super-large and super-small. At present, super-large programmable controllers have emerged, using multiple CPUs to operate together, memory also has super-large capacity. The small modular structure is the trend of the development of the ultra-small programmable controller, and the flexibility will be stronger. Today, with the rapid development of information technology, the development and application of programmable controller technology will usher in a new period of opportunity and have broad prospects for development. The analysis of the working principle of programmable controller can improve its working procedure and apply it to industrial control better. The scientific analysis of its application status and prospect can promote the progress and improvement of the level of the programmable controller industry, and also promote the improvement of the level of industrial control in China.