Programmable logic Controller (PLC) is a kind of real-time embedded computer for industrial control. It can realize all kinds of logic control and flow control through special control language. With PLC as the center, it can build an automatic control system for national defense, manufacturing, rail transit, electric power, water conservancy, municipal and other fields. The PLC system has become the “brain” of the modern digital industrial system, which can fully grasp all kinds of core process data and operation data, and directly determine and guarantee the safe and healthy operation of the national industrial system and national defense equipment system.

1 Domestic PLC development status

In the past 60 years, PLC has realized the leap from relay wiring logic to storage logic in the field of industrial control, from weak to strong, to realize the progress of logic control to digital control, and the application field has grown from small to large, to realize the simple control of single equipment to complex motion control, process control and distributed control and other tasks.

1.1 Development history of domestic PLC

YS1700-000-A34  The development and application of PLC in China from the 1970s, according to the characteristics of development, can be divided into four periods, respectively, the initial development period, the introduction of application period, domestic development period and deep autonomy period, as shown in Figure 1. Initial development period. From the mid-1970s, China developed the first domestic PLC with practical value, which was applied to industrial production control. In this period, mainly to introduce digestion and secondary development of foreign products, in the introduction of production lines, the establishment of joint ventures to introduce foreign PLC production lines, such as the introduction of Siemens S5 series PLC production line in 1986, the establishment of AB PLC production line in 1988, etc.; In the introduction of complete sets of equipment, the introduction of integrated imported PLC complete sets of equipment in the fields of steel and water conservation, replacing the traditional relay to achieve logical control of the process, such as the introduction of more than 200 PLC in the Shanghai Baosteel phase I project to achieve transmission belt control, Shougang No. 4 blast furnace imported PLC to achieve feeding, feeding and battering control. At the same time, in the 1980s, under the organization of the Ministry of Machinery Industry, scientific research institutes represented by the Beijing Institute of Machinery Industry Automation began to develop the first generation of domestic PLC, and successively formed a series of products such as MPC-20, MPC-85, DJK-S-480.

YS1700-000-A34

Figure 1 Four stages of domestic PLC development

Introduction and application period. In the early 1990s, the degree of domestic industrial automation is relatively low, the PLC market capacity is small, and PLC research and development needs to invest more capital and manpower, and there is no return in the short term, some research institutes turn to system integration, the use of imported PLC products to carry out control system engineering applications, imported PLC products gradually occupy the domestic market. Germany’s Siemens, the United States AB and other well-known brands of PLC began to enter the Chinese market, the import of PLC market accounted for 99%.

YS1700-000-A34  Since 1995, China’s PLC market has formed a pattern of large PLC based on Europe and the United States, small PLC based on Japan, and medium-sized PLC evenly divided between Europe and Japan. The technical development and promotion of domestic PLC is relatively slow, but the systematic development of PLC in China has gradually been paid attention to, and in 1991, the PLC Application branch of China Mechatronics Application Association was established to promote the development, production and application of PLC technology and products. In 1993, the national Industrial Process Measurement and control standardization Technical Committee for programmable controller system standardization Technical Committee SAC/TC124/SC5 was established to establish China’s programmable controller and system standard system, which laid the foundation for the development of China’s PLC technology and industry. Localization development period.

After entering the 21st century, with the rapid development of domestic manufacturing industry, PLC demand soared, some enterprises began to enter the field after seeing market opportunities, the development and production of domestic PLC products, in the manufacturing, non-standard machinery, power equipment and other fields have achieved scale applications. However, the domestic PLC in this period is dominated by small PLC products, lack of core technology, basic components are imported products, compared with foreign manufacturers, the industrial scale is relatively small. For example, in 2013, the domestic PLC market size of 7.8 billion yuan, the domestic enterprise Wuxi Xinjie with a cost-effective small PLC market share of 1.6% into the top ten market.

Period of deep autonomy. Affected by Iran’s “Stuxnet virus”, “Prism Gate incident”, Ukraine’s power grid outage incident, the US entity list and changes in the international situation, during the 13th Five-Year Plan period, the state took critical information infrastructure as the top priority of network security, and its control system PLC was included in the management of key network equipment. It opened the journey of deep localization of critical infrastructure control systems. Domestic enterprises have overcome the key core technology of PLC and developed independent safety PLC products based on domestic hardware and software platforms, which are promoted and applied in power generation, rail transit, petroleum and petrochemical energy fields. For example, IM30 series PLC developed by Power Six in 2020 is applied in thermal power, wind power, municipal natural gas and other fields. Deep localization of critical infrastructure has been achieved.