As is well known, Industry 3.0 refers to the electronic and information age, which involves the widespread application of electronic and information technologies to significantly improve the automation level of manufacturing processes. This era began in the 1960s and 70s and continues to the present. PLCs have accompanied Industry 3.0 throughout its development, becoming one of its most representative industrial products.
In January 1968, under the leadership of Richard Morley, Bedford Associates developed a programmable controller that supported ladder logic programming. In October of the same year, Bedford Associates created a new company, Modicon, to promote the industrialization of the new programmable controller; the new product was named Modicon 084.
In November 1969, after learning of General Motors' requirements, Dick Morley demonstrated the Modicon 084 to GM, which won GM's favor. GM subsequently used it to control processes such as metal cutting, drilling, material handling, and assembly. Dick Morley is widely regarded as the "father of PLCs".
In 1971, Allen Bradley engineers Odo Josef Struger and Ernst Dummermuth developed a new generation of controllers, model Bulletin 1774, named the Programmable Logic Controller (PLC). It used a dedicated programming terminal, T3, and this architecture was patented in the United States (US3942158). Odo Josef Struger later became an IEEE Fellow and Vice President of Technology at Rockwell Automation, making significant contributions to Allen Bradley's PLC architecture design and the development of national standards for PLC programming languages.
Looking back at the development history of PLC, its success is reflected in two aspects: first, using computers to analyze the logic control that was previously implemented using relays; and second, adopting ladder diagram logic programming, enabling electrical engineers to use computer programming based on their existing technical skills.
PLC is a product of the development of the industrial economy. It has brought about a revolution in the field of industrial technology, making programmable programs the key to improving the operating efficiency of industrial production equipment and playing an important role in promoting actual industrial production.
With the advent of Industry 4.0 and the era of intelligent manufacturing, enterprises have higher requirements for production line automation, networking, and intelligence. The biggest problem with PLCs lies in their closed and dedicated nature. In today's booming industrial internet era, their closed and dedicated nature has become the biggest obstacle to the development of PLCs.
The architecture of the next generation of PLCs will definitely evolve towards a more open, distributed, fully interoperable, and inherently secure direction. Its software environment must extensively absorb and adopt open-source cloud computing software technologies, and combine them with the requirements and characteristics of industrial automation, thereby forging a development path with lasting vitality.
1. Networking. Networking and enhanced communication capabilities are key aspects of PLC development in recent years. PLCs can connect to multiple PLC control stations and I/O architectures; they can also connect to industrial computers, Ethernet interfaces, MAP networks, etc., forming an automated control system for the entire factory.
2. High reliability. The reliability of automatic control systems has become a focus of attention in the engineering design industry. PLCs have widely applied self-diagnostic technology, redundancy technology, and trial-and-error technology in current products, and many companies have released highly reliable redundant systems.
3. Multifunctionality. PLCs are becoming increasingly versatile to accommodate various unique functions. Based on the original intelligent control modules, various companies have successively released new program modules.
4. Miniaturization, low cost, and ease of use. Many companies are beginning to place great emphasis on miniaturized, low-cost, and easy-to-use system software. Many manufacturers that previously only produced medium and large-sized PLC products are gradually releasing products in this area.
5. Integrated Control and Management Functions. To achieve the necessary control and management for intelligent mass production, PLCs will widely adopt internet-based technologies, wireless communication networks, and graphical optoelectronic technologies, integrating the production control and information management functions of the PLC system software.
6. Programming languages are evolving towards higher levels. PLC programming languages, based on the original ladder diagram language, sequence control language, and command language, are constantly being improved and evolving towards higher levels. Soft PLCs using PC programming technology are becoming increasingly popular.
In summary, the development trend of PLCs is moving towards networking, domestic substitution, high reliability, and multi-functionality; it is also moving towards miniaturization, low cost, and ease of use.
