PLC Programming #4: Functions, Function Blocks & Organization Blocks Explained

PLC Programming: Functions, Function Blocks & Organization Blocks Explained

In this tutorial, I break down the three core building blocks of any PLC program — Functions (FCs), Function Blocks (FBs), and Organization Blocks (OBs). If you've ever been confused about when to use which, or why your program structure matters, this one's for you.

We'll cover:

What Functions, Function Blocks, and Organization Blocks actually are
The key differences between FCs and FBs (and why it matters)
How OBs control your program execution
Instance data blocks and why Function Blocks need them
Best practices for organizing your PLC projects
Live demo in Siemens TIA Portal (concepts apply to any platform)

Whether you're just getting started with PLC programming or cleaning up years of spaghetti code, understanding these block types is essential to writing clean, reusable, maintainable programs.

Resources
PLC used in my tutorials: https://amzn.to/4siePyZ
Support the channel: https://www.patreon.com/LeMasterTech

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