March 4, 2026 · siemenssimatic-axhmiwinccindustrial-automationplc-programming
Siemens just filled the biggest gap in Simatic AX. HMI design.
I recently met with Mario Reger and Stefan Obst from Siemens, who introduced WinCC Unified Elements — the newest member of the Simatic AX family.
One of the problems with Simatic AX was that it covered PLC code only, with no HMI capability. You still needed TIA Portal for your screens.
WinCC Unified Elements changes that.
Two Ways to Design Screens
Built on VS Code (like the rest of AX), WinCC Unified Elements lets you design HMI screens in two ways:
- Visually — similar to TIA Portal’s familiar approach
- In code — every screen and faceplate defined in YAML
Positions, colors, shapes, element properties — all described in text files.
What surprised me: both methods are fully supported. I expected code-only based on how AX works. Having both is a smart move by the Siemens team.
Why This Matters Beyond Convenience
Text-based design means native Git version control. Standard development workflows. And native support for AI-assisted design tools.
This is significant for anyone who has been following the shift toward IT-style workflows in industrial automation. When your HMI screens are defined in YAML files alongside your PLC code in Structured Text, the entire control system project lives in version control. You can diff changes, review pull requests, and integrate AI tools into the design process — things that were never possible with traditional binary project files.
What Is Still Missing
Of course, the AX family still has gaps — safety, drives, motion libraries. But for many applications, AX plus Unified Elements is already a complete solution without ever opening TIA Portal.
The software is not publicly available yet, but the Siemens team is giving me early access to try it. I am confident this is where industrial control design is heading.
The Question for the Industry
Would you switch to code-based HMI design if the tooling supported it? Or do you prefer the visual approach?
My take: having both options is the right answer. Some screens are faster to lay out visually. But when you need consistency across dozens of faceplates, or you want to generate screens programmatically, code-based design wins.
Originally published on LinkedIn.
