Why Structure Matters: Transforming PLC Programming
Industrial automation professionals and IoT enthusiasts will find strong practical guidance in this conversation between Hans Schrynemakers, a seasoned control and automation engineer, and hosts Phil Seboa and Ed Fuentes. The discussion centers on the importance of structured PLC programming, effective communication through naming conventions and documentation, and the accelerating integration of modern automation technologies. These points matter to anyone seeking reliability, maintainability, or innovation in automation systems.
Hans Schrynemakers explains that early in his career, a lack of structure led to stressful nights troubleshooting "spaghetti code" in PLC applications. He recounts, “I was just writing code. I was not really thinking that much about structure back then...just trying to make the machines run without any further thought.” This experience led him to adopt a highly organized, modular programming style—breaking systems into manageable blocks.
This modular structure allows for easier troubleshooting, smoother scaling, and quicker adaptation when requirements change. As Hans notes, taking a “step back and look at the application,” mapping out its modules, and mirroring that structure in the PLC, is a crucial first step, ahead of any coding or language decisions. Modular programs are not only easier to support but also allow multiple programmers to collaborate effectively without introducing chaos.
Miscommunication in automation projects is all too common, and Hans emphasizes the importance of clear naming and documentation. “If you have a tag that's called KLM25, obviously you need some comment to tell what's going on here,” he explains. Preferably, though, the name itself should be descriptive enough that extra commenting becomes secondary.
Hans recommends naming approaches such as Hungarian notation—using clear prefixes for inputs, outputs, or data types—to give every tag an instant, obvious meaning. “Having a clear...signaling. Is this an input? Is it an output? Is it an in out that you can read that directly from the tag, for me personally, is a huge help when troubleshooting a block.” He describes concise, consistent comments as vital, but cautions that the foundation is in clear structure and tag names, which reduce errors and improve collaboration.
The move from isolated software tools to integrated automation platforms has changed the work of automation professionals. Hans recalls when working with Siemens required juggling three separate packages for PLC, HMI, and motion control. “Nowadays...everything is just, yeah, seamless. And that's what Siemens has been doing as well, very strongly with TIA Portal in the last decade.”
This integration means today’s programmers must learn across disciplines: PLC logic, motion, process control, safety, and network connectivity. Hans says his favorite projects are those that allow him to apply all these tools, particularly when motion control and rapid, synchronized machine movements are involved. He emphasizes that learning on the job—adapting to new devices, platforms, and communication standards—is simply part of staying current in the field.
"I stopped thinking of software just as a collection of bits and bytes, but I started to think more of an application built into modules...It was a huge step up for me to see that kind of structural modularity throughout the machines." — Hans Schrynemakers
Structured, modular PLC applications, supported by clear naming and thorough documentation, set the foundation for robust, maintainable automation systems. Integrated platforms further improve productivity, and a commitment to ongoing skill-building ensures long-term success. Readers should review their software structure, establish explicit naming standards, and invest time in both documentation and continuous learning to meet industry demands.
Hans Schrynemakers is a Belgian control and automation engineer with over twenty years of practical experience in PLC programming and motion control, primarily with Siemens and Rockwell systems. Through his online courses, YouTube channel, and coaching, he provides programmers worldwide with the tools and mindset needed to create reliable, modular automation solutions.