CLASS vs FUNCTION_BLOCK in SIMATIC AX — Explained for TIA Portal Engineers
April 8, 2026 — A deep dive into the two main building blocks of SIMATIC AX — FUNCTION_BLOCK and CLASS. What each one supports, when to use which, and how they fit together in real projects. Written for TIA Portal engineers who already know function blocks.
What Is the Future PLC Programming Tool of Siemens: Simatic AX or TIA Portal?
March 31, 2026 — The question is no longer what tool is more convenient for humans. The question is what tool is more convenient for AI agents. My take on Simatic AX vs TIA Portal.
How to Write Unit Tests in SIMATIC AX — A Step-by-Step Guide for TIA Portal Engineers
March 27, 2026 — A hands-on guide to writing unit tests in SIMATIC AX using AxUnit. Walks through the anatomy of a test file, the reset pattern, assert methods, running tests, and what to test versus what to leave for commissioning.
Unit Testing in SIMATIC AX — I Proved My PLC Code Works Without a PLC
March 25, 2026 — What unit testing is, why TIA Portal engineers should care, and how SIMATIC AX's built-in AxUnit framework lets you verify PLC code automatically — no hardware needed.
SIMATIC AX Project Structure Explained for TIA Portal Engineers
March 17, 2026 — A complete mapping of TIA Portal concepts — OBs, FBs, FCs, DBs, tag tables — to their SIMATIC AX equivalents. The reference guide for PLC programmers making the switch.
Namespaces in SIMATIC AX Explained for TIA Portal Engineers
March 17, 2026 — A deep dive into namespaces — what they are, why TIA Portal does not have them, how to use them in AX, and the mistakes you will make if you think about them with TIA Portal logic.
Two Types of SIMATIC AX Projects — Full AX vs TIA Portal Hybrid
March 11, 2026 — When you run apax create, you face a choice between two fundamentally different project types — full AX engineering or a hybrid with TIA Portal. Here is how they differ and which one to start with.
You Don't Need AX Code IDE — SIMATIC AX Runs From Any VS Code Workspace
March 10, 2026 — SIMATIC AX is fully CLI-driven. You can run apax commands from any terminal inside your normal VS Code workspace — no AX Code IDE required.
Siemens Just Filled the Biggest Gap in Simatic AX — HMI Design
March 4, 2026 — WinCC Unified Elements brings code-based HMI design to the Simatic AX family — visual and YAML-based screen design in VS Code, with native Git support.
Multi-Instance vs Single-Instance Function Blocks in TIA Portal
December 5, 2025 — Learn why multi-instance function blocks in TIA Portal are better than single-instance for reusable, library-ready PLC code.
Why You Should Avoid Using Merkers (M Bits) in Modern TIA Portal Programs
November 24, 2025 — M bits cause hidden bugs, kill reusability, and make maintenance painful. Here is why DB tags, UDTs, and FBs are the better choice.
Understanding the InOut Interface Pattern in TIA Portal
October 3, 2025 — How to use InOut interfaces with UDTs to create a clean, scalable data architecture for your TIA Portal PLC programs.
