Five Key Differences in Programming Approaches Between PLC Engineers in Germany and China (Collectible and Educational)

The differences in programming approaches between PLC engineers in Germany and China are primarily reflected in technical concepts, development processes, tool usage, industry standards, and cultural backgrounds. Germany has a deep-rooted industrial automation culture and rigorous engineering practices, while China has rapidly developed in this field in recent years but started later, leading to significant differences in PLC programming methods. The following analysis details these differences from multiple dimensions:

1. Technical Concepts and Design Philosophy

• German PLC Engineers:

  • Modular and Structured Programming: German engineers place great emphasis on modular design, preferring to decompose programs into clearly defined modules (such as Function Blocks (FB) and Functions (FC)). They typically adhere to the IEC 61131-3 standard, prioritizing the use of Structured Text (ST) or Ladder Diagram (LD) languages to ensure code reusability and maintainability.

  • Focus on Long-term Stability: The industrial culture in Germany emphasizes long equipment lifecycles (over 20 years), thus program design centers around stability and scalability, focusing on the universality and compatibility of code.

  • Standardization and Norms: German engineers strictly follow industry standards (such as IEC, DIN), and their code often includes detailed comments and documentation to ensure ease of understanding during team collaboration. Program logic is typically concise, eliminating redundant code.

  • Preventive Error Handling: German engineers consider various exceptional situations (such as sensor failures or communication interruptions) during programming, enhancing system robustness through fault diagnosis modules.

• Domestic PLC Engineers:

  • Pragmatism and Rapid Implementation: Domestic engineers tend to prioritize quick functionality implementation, especially under tight project timelines, often focusing on task completion over long-term maintainability. The level of code structuring is relatively low, and modular design is not widely used.

  • Flexibility and Customization: Domestic engineers often customize development based on specific project requirements, resulting in code that may be more tailored to specific devices or scenarios but lacks general applicability.

  • Fewer Comments and Documentation: Due to time pressures or habits, domestic engineers often provide less commentary and documentation in their programs, which can lead to difficulties in later maintenance.

  • Simplistic Exception Handling: Domestic engineers tend to have less pre-processing for exceptional situations during programming, relying more on on-site debugging and temporary fixes.

2. Programming Language and Tool Selection

• German PLC Engineers:

  • Language Preference: They prefer using Structured Text (ST) or Function Block Diagram (FBD) as these languages are suitable for complex logical control and cross-platform portability. Ladder Diagram (LD) is mainly used for simple logical control.

  • Toolchain: German engineers often use mature development environments such as Siemens TIA Portal, Beckhoff TwinCAT, or Rockwell Studio 5000. These tools support advanced features like simulation, online monitoring, and diagnostics.

  • Code Reusability: German engineers widely use standardized function block libraries (such as Siemens SCL library, OSCAT library) to improve development efficiency and code consistency.

• Domestic PLC Engineers:

  • Language Preference: Ladder Diagram (LD) is the most commonly used programming language among domestic engineers due to its intuitiveness and ease of debugging. The use of Structured Text (ST) or Instruction List (IL) is less common, mainly due to training and experience limitations.

  • Toolchain: Domestic engineers often use PLC development environments from brands like Siemens, Mitsubishi, and Omron, but the utilization of advanced tool features (such as simulation and version management) is relatively low. Some small to medium-sized projects may use domestic PLCs (like Xinjie, Huichuan), whose development tools are relatively simple.

  • Less Code Reusability: Domestic engineers tend to develop from scratch rather than using standard libraries, leading to lower development efficiency and inconsistent coding styles.

3. Development Process and Project Management

• German PLC Engineers:

  • Systematic Development Process: German engineers typically follow a V-model or similar project management process, which includes clear stages such as requirements analysis, functional design, coding, testing, validation, and delivery.

  • Simulation and Testing: After programming is completed, German engineers conduct extensive simulation testing (using PLCSIM or TwinCAT simulation environments) to ensure that the program is free of logical errors before actual production.

  • Version Control: Code version management is standard practice, commonly using tools like Git or the version control features of TIA Portal to ensure code traceability during collaborative efforts.

• Domestic PLC Engineers:

  • Flexible but Unfixed Processes: The development process for domestic PLCs is often more flexible, lacking unified standardized management, especially in small to medium-sized projects where requirements may frequently change during development.

  • Reliance on On-site Debugging: Domestic engineers tend to prefer discovering and solving problems through on-site debugging, with less application of simulation testing, partly due to equipment or software cost constraints.

  • Limited Version Management: The use of version control tools is not widespread, and code modifications often depend on personal habits, which can lead to confusion during collaborative efforts.

4. Industry Standards and Norms

• German PLC Engineers:

  • Strict Adherence to International Standards: German engineers strictly comply with international standards such as IEC 61131-3 and ISO 13849 (safety standards) to ensure that programs meet safety and compliance requirements.

  • Industry Template Usage: In industries such as automotive, chemical, and energy, German engineers often use industry-specific templates or standard libraries (such as the VDA standard in the automotive industry) to ensure consistency.

  • Safety First: Functional safety is at the core of PLC programming in Germany, with engineers designing redundant logic and safety circuits (such as SIL levels).

• Domestic PLC Engineers:

  • Inconsistent Standard Execution: Although domestic practices also reference standards like IEC 61131-3, the enforcement varies by company size and industry. Small to medium-sized enterprises may overlook certain standards, prioritizing cost over compliance.

  • Fewer Industry Templates: Domestic PLC programming uses fewer industry templates, often relying on experience or device manuals for development.

  • Increasing Safety Awareness: In recent years, there has been a growing emphasis on functional safety in China, but it still lags behind Germany, especially in small to medium-sized projects where safety logic implementation is relatively basic.

5. Culture and Work Habits

• German PLC Engineers:

  • Precision and Discipline: German engineers are known for their meticulousness, with a unified programming style that emphasizes detail and the pursuit of “doing it right the first time.” They typically follow established plans and avoid last-minute changes.

  • Team Collaboration: PLC development in Germany is usually a team effort, with programmers, electrical engineers, and mechanical engineers working closely together with clear divisions of labor.

  • Comprehensive Training System: Germany’s vocational education system (such as Ausbildung) provides PLC engineers with a solid theoretical and practical foundation, resulting in engineers with high professional competence.

• Domestic PLC Engineers:

  • Flexibility and Quick Response: Domestic engineers are more accustomed to handling urgent tasks and last-minute customer demands, leading to varied programming styles that are flexible but lack uniformity.

  • Individual Heroism: In some small to medium-sized enterprises, PLC development may be led by a few core engineers, resulting in lower levels of team collaboration.

  • Insufficient Training: Domestic PLC engineers often rely on internal company training or equipment suppliers, lacking systematic education, and novice engineers may learn programming through self-study or imitation.