PLCs emerged as a product of the Industrial 3.0 era. Over more than five decades of development, the technology has continuously innovated, and the range of products has steadily expanded. As the brain controlling industrial production systems, PLCs replaced the relays previously used to control high-power equipment. This transition saved manufacturing space, reduced power consumption, and decreased the workload for engineers in equipment maintenance.
Currently, as industrial manufacturing transitions toward Industry 4.0, manufacturing enterprises must undergo transformation and upgrading. This involves not only enhancing the automation level of manufacturing equipment but also integrating internet technology with industrial control systems. By leveraging consumer data, supply chain management can be optimized, and factory production planning rationalized. Consequently, in industrial automation, the PLC, serving as the "brain," plays a crucial role in this new wave of industrial transformation.
Today's PLCs are no longer traditional PLCs
Simply put, a PLC is a computer dedicated to industrial control. It uses programmable memory to store instructions, executing logic, sequencing, timing, and computational functions. Through analog or digital I/O modules, it controls various mechanical production processes. The CPU serves as the PLC's brain, executing user programs while aggregating, analyzing, and processing information gathered from other modules.
Smart factories feature comprehensive sensing, optimized decision-making, and precise execution, enabling autonomous business management and manufacturing operations. Achieving smart manufacturing necessitates multifunctional, high-performance industrial controllers. In past industrial settings, a single piece of equipment, process segment, or production line might require multiple controllers-for example, an industrial robot platform using a robot controller + PLC, or a flexible machining unit employing CNC + PLC. Future smart factories require a single "brain" to control all units.
Dr. Wei Rong Xiao, President of B&R Greater China, stated in an online lecture that today's PLCs are no longer traditional PLCs. He pointed out that traditional PLCs execute multiple tasks sequentially, repeating the cycle. In contrast, B&R's new generation of PLCs, based on multiple tasks within a single project, divides the system into multiple task levels. Each task corresponds to a cycle, with priority levels set according to cycle duration.
This demonstrates that the new PLCs are not merely executing simple logic tasks but are capable of handling more complex processes on production lines. In emergency situations, the multitasking capabilities of the new generation PLCs prevent the need for interrupt handling, unlike traditional PLCs. In other words, today's industrial production systems require a highly intelligent PLC as their "brain."
Industry experts also note that modern large-scale PLC systems are inherently distributed computing systems based on fieldbuses and local area networks. Applying technologies supporting cloud-based distributed computing to industrial control will revolutionize system architecture, technical frameworks, product forms, and application methods. As manufacturing transitions toward intelligent manufacturing, numerous research topics remain in the PLC field.
What kind of PLC meets the requirements of Industry 4.0?
Against the backdrop of Industry 4.0, factory networks are evolving from closed local area networks to interconnected systems with external entities. Consequently, the communication model for PLCs must also adapt. PLC communication systems can form more complex control networks using protocols like Profinet, CC-Link, or DeviceNet. However, many PLCs remain incompatible with the barcode scanners, RFID readers, sensors, and industrial cameras required in smart factories. Smart manufacturing hinges on data acquisition. Factory data-including material management and equipment monitoring-must integrate into MES systems to provide robust hardware foundations for comprehensive digitalization across production, logistics, warehousing, and marketing management.
This reveals significant challenges in developing an Industry 4.0-compliant PLC, awaiting resolution by R&D professionals.
First, it must handle massive production data and increasingly complex algorithms. Under smart manufacturing, PLCs inevitably need to store greater volumes of production data. On one hand, consumer demand for product personalization and quality is rising, requiring factories to enhance production techniques while reducing manufacturing costs. Consequently, the underlying control system must process vast amounts of production data and logical relationships. On the other hand, handling such data imposes higher demands on the algorithms behind PLC hardware. Developing robust algorithms inherently involves significant technical barriers.
Second, the simplicity of supporting programming software design is crucial. As consumer expectations for products rise, factory production complexity inevitably increases. PLCs must now perform functions like PID control, network communication, high-speed calculations, position control, data logging, and text display. This means programming difficulty is constantly escalating. Furthermore, PLC programming languages vary across different brands on the market, requiring engineers to master multiple languages. From the end-user procurement perspective, a truly practical PLC product enables engineers to learn once and apply their skills universally. This reduces corporate costs in personnel training, technical consulting, system debugging, and software maintenance.
Thirdly, understanding the operational habits of engineers in specific downstream application scenarios. In PLC usage, users encounter distinctions between so-called Japanese and German systems, each with its own strengths in software programming. As PLCs integrate software and hardware, different application scenarios necessitate corresponding software adjustments. Moreover, varying scenarios give rise to distinct operational habits among engineers. Conversely, PLC suppliers must adapt generic PLC software to address these industry-specific operational preferences. Regardless of the sector, software programming for PLCs in modern manufacturing environments increasingly prioritizes simplicity and ease of operation.
Competitive Landscape of China's PLC Market
As the world's largest manufacturing hub, China naturally boasts massive PLC usage. The domestic PLC market is dominated by European, American, and Japanese brands.
Among European and American brands, Siemens, Rockwell, and Schneider are prominent. Siemens excels across small, medium, and large-scale products, establishing itself as a primary supplier in China's PLC market with a 40.7% market share in 2016 alone. Rockwell maintains a leading position in the large PLC segment, holding a 10.1% market share. Schneider, as a long-established PLC supplier, has consistently maintained a market share of around 9%. Among Japanese brands, Mitsubishi and Omron stand out. Leveraging their cost-performance ratio and market channel advantages, they maintain a high level of competitiveness in the domestic market.
Additionally, Taiwan-based Delta, with its high cost-performance advantage, has deeply penetrated the OEM market. By persistently pursuing integrated solutions combining PLCs with variable frequency drives and servo drives, Delta has sustained rapid growth in market sales.
Regarding domestic PLCs, their development spans nearly 40 years. This history can be broadly divided into three phases: the introduction period from the 1980s to the 1990s, when all PLCs on the market were overseas brands; the start-up phase for domestic industrial control enterprises from the 1990s to 2000, when domestic PLC brands began to emerge; and the development phase for domestic PLC brands after 2000.
Domestic brands started with small PLCs, which have lower technical barriers, and leveraged their localized advantages to achieve rapid growth. In recent years, they have made significant inroads into the mid-sized PLC market.
Conclusion
PLCs are indispensable components of factory automation and industrial process control. In the era of smart manufacturing, heightened demands on PLC performance are inevitable, necessitating a fundamental redesign encompassing high-performance control, interoperability, secure communication, cross-platform operation, and future-proofing. From a market perspective, PLCs face channel barriers. The market for a single PLC product from industrial automation companies typically has an invisible ceiling. Taking foreign high-end brands as an example: First, leverage their own strengths to identify suitable entry points; second, after gaining customer recognition, gradually enhance the R&D of industrial chain products, transforming from a single supplier into a solution provider; finally, leverage technological accumulation and brand advantages to become a comprehensive supplier spanning the mid-to-high-end markets.