As the preferred product of discrete control system, PLC developed rapidly from 1980s to 1990s, and the annual growth rate of global PLC usage remained at 20% ~ 30%. With the continuous improvement of factory automation level and the continuous expansion of PLC market capacity base, the growth rate of PLC in industrialized countries has slowed down in recent years. However, in developing countries such as China, the development of PLC is very rapid. According to relevant data, the global sales revenue of PLC in 2004 was about $654.38+000 billion, which occupied a very important position in the field of automation.
Learning PLC must have elementary mathematics knowledge, among which fractions, algebraic expressions, functions and linear equations are the key points of learning, and also the knowledge often used in PLC programming.
No matter IT programming or automatic programming, it is inseparable from basic knowledge such as number system, code system and decimal system.
The basic knowledge of electrotechnics that must be mastered mainly includes the basic knowledge of electrotechnics and electronics technology, the basic knowledge of circuit analysis, common electrical instruments and their measurement. If you are an electrician and master the knowledge of elementary mathematics, number system and coding system, you can directly learn the basic knowledge of PLC.
Once you have mastered the above points, you can start learning PLC. It is recommended to study Mitsubishi fx series or Siemens 200 first, download the instructions and read more. This manual is equivalent to the manual of PLC. You can go to the technical training network to watch the PLC free live class, and the two-month cycle starts from scratch.
Development trend of PLC
With the increasing application of PLC, PLC technology and its product structure are constantly improving, with more and more powerful functions and higher cost performance.
(1), in terms of product scale, developing towards two poles. On the one hand, we will vigorously develop small and ultra-small PLCs with faster speed and higher cost performance. Meet the needs of single machine and small automatic control. On the other hand, it is developing to a large-scale PLC with high speed, large capacity and perfect technology. With the continuous improvement of complex system control requirements and the continuous development of microprocessor and computer technology, people have higher requirements for the information processing speed of PLC, and the storage capacity of users is also increasing.
(2) Developing to communication network.
PLC network control is the development trend of current control system and PLC technology. Networking communication between PLC and PLC, and networking communication between PLC and host computer have been widely used. At present, PLC manufacturers are developing their own special communication modules and communication software to strengthen the networking ability of PLC. Various PLC manufacturers are also negotiating to formulate a common communication standard to form a larger network system. PLC has become an indispensable part of distributed control system (DCS).
(3) Developing towards modularization and intelligence.
In order to meet the needs of various control systems of industrial automation, in recent years, PLC manufacturers have developed many new devices and modules, such as intelligent I/O module, temperature control module and special intelligent module for detecting PLC external faults. The development and application of these modules not only enhance the function of PLC, expand the application scope of PLC, but also improve the reliability of the system.
(4) Diversification and standardization of programming languages and programming tools.
The coexistence, complementarity and development of multiple programming languages is the development trend of PLC software. While making hardware and programming tools change frequently, enriching and improving their functions, PLC manufacturers are increasingly moving closer to MAP (Manufacturing Automation Protocol) to standardize and standardize the basic components of PLC, including input and output modules, communication protocols, programming languages and programming tools.