The Growing Sophistication of PLC Coding Standards > 자유게시판

The advancement of industrial control programming has been shaped by the growing complexity of process control systems and the requirement for more effective, stable, and user-friendly tools for industrial maintenance crews. In the initial phase of programmable logic controllers, programming was implemented with low-level programming languages such as ladder logic, which was designed to mimic the wiring diagrams of mechanical relays. This made it intuitive for electricians and maintenance personnel who were already familiar with traditional switchgear systems. Ladder logic emerged as the industry norm because of its visual simplicity and ease of troubleshooting.

As manufacturing processes became more advanced, the shortcomings of ladder logic became undeniable. While excellent for on, it was ill-equipped for advanced calculations, data handling, and communication protocols. This led to the adoption of Structured Text, a high level language analogous to ALGOL-derived languages, which allowed for more space-efficient and robust code. Structured text gave engineers the ability to develop logic for complex operations like proportional-integral-derivative loops, historical data collection, and product configuration systems with enhanced readability and performance.

IL, another initial coding method, offered a concise text-based syntax of logic operations and was commonly adopted continental Europe. It was low-overhead for simple tasks and had low memory footprint, making it well-matched to first-generation controllers with basic hardware capabilities. However, its minimal syntax rules and readability made it harder to maintain in enterprise-scale applications.

Function Block Diagram emerged as a diagram-based approach that allowed engineers to represent logic as modular units, each executing a defined task. This approach was particularly effective for modular programming and code reuse. Function blocks could be standardized and redeployed across multiple control modules, shortening project cycles and maintaining standardization. This also made it facilitated cross-functional teamwork since the visual nature of the language facilitated understanding across disciplines.

Sequential function chart was introduced to control multi-stage operations with numerous states and conditionals, such as those found in batch processing. It provided a structured methodology for structuring control flow as stages and triggers, making it easier to visualize time-based control sequences.

The International Electrotechnical Commission established the global PLC programming standard in the 1990s, which codified the five core PLC languages: ladder diagram, 転職 技術 Structured Text, Instruction List, function block diagram, and Sequential Function Chart. This standardization helped bring consistency to the field and allowed for interoperable programs between competing industrial brands.

Currently, advanced HMI often combine all IEC 61131-3 languages within a integrated engineering environment, allowing engineers to pick the best-suited method for each part of the application. For example, a system might use LD for actuator sequencing, graphical modules for I, and ST for mathematical algorithms.

The direction is moving toward increased abstraction, convergence with enterprise IT, and encapsulation and inheritance in control code. Remote monitoring, secure firmware updates, and real-time performance insights are now shaping development practices. As a result, the role of the PLC programmer has shifted from a hardware-centric operator to a cross-disciplinary engineer skilled in control systems and network protocols.

The evolution of PLC programming languages reflects the fundamental transition in industrial automation from electromechanical to software-driven, from isolated systems to interconnected networks, and from binary logic to adaptive control. While the core purpose of PLCs remains the same—to control machines reliably and safely—the tools we use to program them have become more capable, modular, and intuitive, equipping future engineers.