CODESYS vs a Browser PLC Simulator: Which Fits?

Codesys is a serious piece of software. It's the runtime embedded inside PLCs from WAGO, Beckhoff, IFM, Eaton, ABB's MicroBrowser, and dozens of smaller OEMs — if you buy a non-Rockwell, non-Siemens PLC in 2026, chances are good it's running Codesys underneath. The Codesys Development System is the free desktop IDE that programs all those controllers.

Our simulator is a browser-based curriculum platform with 140 published scenario records, nine learning dialects, and built-in interview prep. Different product, different user, different use case. This post explains the difference honestly and suggests a sequence that uses both.

What Codesys actually is

Three components:

1. Codesys Development System — the free Windows IDE. Full IEC 61131-3 support across six languages (LD, FBD, ST, SFC, IL, CFC). Mature, powerful, occasionally baroque.
2. Codesys Control Runtime — the soft PLC that executes your code. Free for development use; paid license per-target in production. Runs on Linux, Windows CE, RT variants, and many embedded platforms.
3. Vendor-specific plug-ins — each vendor that embeds Codesys adds its own libraries and target support in the IDE. WAGO, Beckhoff, etc.

The Development System is free. Buying a Beckhoff PC-based PLC means you're already paying for the runtime license bundled with the hardware.

What our simulator is

• Browser-based PLC learning platform
• 140 published scenario records with automated test cases; visible access varies by plan and rollout
• 55 learning modules + 12 quizzes + 6 interview tracks
• Nine learning dialects, including IEC 61131-3, Allen-Bradley-style, Siemens, Mitsubishi, Omron, KEYENCE, Schneider, Delta and Instruction List
• USD 0 free tier (27 source-tagged practice records; visible access can vary), USD 99/year Basic, USD 249/year Pro
• No install, any OS

Curriculum-led where Codesys is tool-led.

Head-to-head

The tools are solving different problems. Codesys is the tool a working engineer uses to program real hardware. Our simulator is the curriculum that teaches someone how to be that engineer.

When Codesys is the right answer

• Your target job runs Codesys-based hardware. WAGO PFC, Beckhoff CX, IFM ecomat mobile, Eaton XC — all Codesys underneath. Learn Codesys for those.
• You need SFC or CFC. Our simulator covers LAD and ST, not SFC or CFC. If your work is recipe-driven (brewery, pharma) or motion-heavy (CNC), Codesys supports both natively.
• You're an experienced programmer who doesn't need curriculum. Codesys is powerful but unguided. Fine if you already think in scan cycles.
• You want the most widely-embedded runtime to understand. Knowing Codesys deeply pays off across many vendor ecosystems.
• You have a Windows machine and don't mind the install.

When our simulator is the right answer

• You're learning PLCs from scratch. You need curriculum, graded tests, and solutions to compare against. Codesys supplies none of that.
• You need to read code across vendors. Four dialects in one UI beats four separate tools.
• You're on a Mac, Chromebook, or iPad. Codesys refuses; we run.
• Interview prep matters. The six tracks with downloadable certificates is a specific product feature nobody else offers.
• You don't yet know whether you'll stick with PLCs. Free tier + no install is the right on-ramp.

The hybrid sequence

Most serious learners end up using both:

1. Weeks 1–8: Our simulator. Learn fundamentals, write 20 scenarios, get your first two interview-track certificates.
2. Weeks 9–10: Download Codesys Development System. Port a few of your scenario solutions into Codesys. Notice what's identical (the logic) and what's specific (the IDE chrome, the library catalog, the device tree).
3. Week 11+: If your target job is Codesys-based, work in Codesys. If it's Rockwell or Siemens, use their tools instead. Either way, keep our simulator for multi-dialect fluency and interview prep.

This sequence works because it separates learning from tooling. Most people try to learn from a tool and burn out on install friction before they've written a rung.

Common confusion

• "Is Codesys a PLC?" No. Codesys is the software (IDE + runtime). A PLC is hardware. Codesys runs on many vendors' PLCs.
• "Is Codesys a simulator?" It includes a soft PLC for testing, which simulates execution. It does not include machine physics or learning scenarios.
• "Is Codesys better than Rockwell or Siemens?" Different market. Codesys-based PLCs are common in European process, building automation, and OEM machinery. Rockwell dominates North American manufacturing. Siemens dominates European automotive. Learn whichever your target requires.

FAQ

Is Codesys free?

Codesys Development System (the IDE) is free. The runtime is free for development; commercial runtime deployment is paid via your PLC manufacturer.

Is Codesys good for beginners?

For experienced programmers, yes. For complete PLC beginners without curriculum support, it's tool-heavy without guidance. Pair it with a learning resource.

What's the best Codesys tutorial?

Codesys publishes an official "Getting Started" PDF. RealPars YouTube channel has solid Codesys-specific videos. Our 12-week PLC course builds the fundamentals that make Codesys easier.

Can I learn Codesys in a browser?

Not natively. Codesys is a desktop product. For browser-only practice, our simulator covers the same IEC 61131-3 semantics with dialect toggles.

Which PLCs use Codesys?

WAGO PFC100/200, Beckhoff CX-series, IFM ecomat, Eaton XC-series, ABB AC500 (subset), and many smaller vendors. Check your target's documentation.

Where to start

1. Complete beginner: sign up free and finish 2 scenarios. Then read this post again.
2. Experienced programmer: download Codesys Development System directly. Work through the official Getting Started guide.
3. Career-focused learner: use our simulator for curriculum (Weeks 1–10), then add Codesys in Week 11 if your target job requires it.

Two tools, two problems, one sequence. Pick the right one for where you are right now.