Real machine physics
Every scenario simulates real equipment. Tanks fill, motors spin, valves modulate — driven by your actual ladder logic.
Zero install
Free Online PLC Simulator — Runs in Any Browser
No download. No JRE. No license key. Write ladder logic or Structured Text in a browser tab and watch a simulated machine respond — on a Chromebook, a Mac, Linux, or a locked-down corporate laptop.
How it feels
Built to build intuition.
A browser tab that behaves like a real PLC bench — without the hardware budget.
Live I/O experimentation
Toggle inputs by hand to see how the PLC responds. No wiring, no hardware — just click and learn.
Certificate-backed interview prep
Pass an interview track and earn a downloadable PDF certificate. Pro users get solution walk-throughs with expert commentary on every scenario.
This is an online PLC simulator running live in this browser tab. No install happened to show you this.
Why online
Why an online PLC simulator changes everything.
An online PLC simulator is a programmable logic controller emulator that runs inside a web browser instead of as installed desktop software. You open a URL, write ladder logic or Structured Text, press Run, and a simulated machine responds in real time — driven by the same read-inputs, solve-logic, write-outputs scan cycle a physical PLC CPU executes. Because it is a browser PLC simulator, there is nothing to download, no JRE, no license key, and no operating-system requirement. You can be writing your first rung within 30 seconds of clicking a link.
Traditional PLC simulators are desktop Windows installs. Siemens PLCSIM ships bundled inside TIA Portal — a multi-gigabyte download that requires a Windows machine and a Siemens license. Rockwell's Studio 5000 Logix Emulate is Windows-only and paid. LogixPro is a commercial teaching tool that runs only on Windows. Even OpenPLC Editor, which is free and open-source, is a desktop application you download and install. Every one of these options locks out Chromebook users, Linux users, corporate IT-restricted machines, and anyone without admin rights on their device.
A browser-based online PLC simulator removes every one of those barriers. There is no installer because there is nothing to install. The application is a URL. You type it, the browser loads it, and you are writing ladder logic within 30 seconds. That is the entire friction model. Students on shared university Chromebooks, engineers pulling up a quick logic check from a hotel room, and trainees who have never heard of PLC programming before can all start from the same place.
Modern browsers make this possible without compromise. Chrome, Firefox, Safari, and Edge all ship with WebGL support baked in. The simulator uses Phaser 3 for its rendering pipeline, which targets WebGL by default and falls back to Canvas. JavaScript execution speed in V8 and SpiderMonkey in 2025 is fast enough to run a real scan cycle and a physics model simultaneously. This is not a simplified toy — it is a plc programming online simulator with the same scan-cycle mechanics you would expect from a real controller, running in a browser tab.
Device support
Works on any device, no exceptions.
If the device has a browser with WebGL, it runs the online PLC simulator. That covers essentially every device sold in the last eight years.
Chromebook
The cheapest path to PLC learning. Most K-12 and community-college PLC labs use Chromebooks. Every PLC desktop tool locks those students out. Our online PLC simulator runs on any Chromebook with no workarounds — just open Chrome and type the URL.
Mac and Linux
No mainstream PLC IDE ships a native Mac or Linux build. PLCSIM, Studio 5000, LogixPro — all Windows. If you run macOS or Linux you have historically needed a VM just to practice ladder logic. Not any more.
Locked-down corporate Windows
Corporate IT locks software installs behind admin rights for good reason. That same policy has historically blocked PLC students and engineers from running simulator software on their work laptops. A browser URL needs no admin rights, no MSI, no UAC prompt.
Tablet and iPad
The Monaco editor is touch-capable. The Phaser 3 canvas scales responsively. You can write a ladder rung, hit Run, and watch the machine respond on an iPad — a genuinely useful feature when you're reviewing logic away from a desk.
Performance
Browser-based does not mean slow.
The honest concern with any online simulator is performance. A desktop tool compiles to native code and talks directly to the GPU driver. A browser app runs JavaScript through a JIT compiler and reaches the GPU via WebGL. The gap used to matter. On modern hardware with a modern browser, it does not.
The simulator uses Phaser 3 as its rendering engine. Phaser targets WebGL by default, which means the scene primitives — tanks, conveyors, motors, lamps, pipes — all render on the GPU. The scan cycle and IO table run in a separate JavaScript loop. The two stay independent, so a heavy scenario does not drop your frame rate, and a high-frequency scan cycle does not stall the animation.
In recent testing across the scenario library, the rendering pipeline holds a consistent frame rate on post-2017 devices. The table below shows measured fps across a sample of scenarios on a mid-range laptop.
| Scenario | Objects in scene | Observed fps (Chrome) | Observed fps (Firefox) |
|---|---|---|---|
| Traffic Light | Low (~12) | ~60 | ~60 |
| Motor Start / Stop | Low (~10) | ~60 | ~60 |
| Conveyor Sort | Medium (~30) | ~60 | ~58 |
| Batch Mixer | Medium (~35) | ~60 | ~57 |
| Bottling Line | High (~55) | ~58 | ~55 |
Measured on a 2019 i5 laptop, Chrome 124, Firefox 126, integrated GPU. Results will vary by hardware.
Under the hood
What actually runs in the browser?
The free online PLC simulator is not a server-side emulator streaming video to your screen. Everything that matters — the scan cycle, the IO table, the machine physics, the test harness — runs entirely in your browser tab as compiled JavaScript. The server serves the application bundle once; after that your device does the work.
Concretely: a scan cycle engine reads your ladder logic or Structured Text, evaluates every rung against the current IO table, and writes outputs — exactly as a real PLC CPU would. The cycle repeats on a configurable interval (default 10 ms). A Phaser 3 rendering loop reads those outputs and animates the machine: motors spin, conveyors move, tanks fill, lamps illuminate. The two loops run independently on separate requestAnimationFrame timers so a slow render never delays the scan.
The Monaco editor (the engine inside VS Code) handles code editing, dialect-specific syntax highlighting, and inline error marking. When you click Run, the engine compiles your source into an instruction list, resets the IO table, and starts the scan. When you click Grade, a scripted test harness replays a sequence of input events and asserts that your outputs responded correctly — checking sequencing, timing windows, and edge-case interlocks.
Free online PLC simulator vs install software — the main trade-off is depth of hardware integration. Desktop tools like PLCSIM or RSLogix Emulate can mirror a real controller configuration, connect to physical I/O over EtherNet/IP, and test code you intend to download to a rack. The browser simulator cannot do that. What it can do — and desktop tools largely cannot — is run on any device, cost nothing to start, and give you immediate auto-graded feedback on 40 machine scenarios without any configuration. For learning, interview prep, and skills refreshes, that trade-off is strongly in the browser's favour.
Capabilities
What you can do in an online PLC simulator.
The online simulator is not a simplified demo. It is a full PLC programming simulator that happens to need nothing beyond a browser. Here is what you can do inside it:
- 1Write ladder logic — contacts, coils, timers, counters, latch/unlatch, edge detection, compare, and math instructions.
- 2Write Structured Text following the IEC 61131-3 standard — portable to Codesys, OpenPLC, and any ST-compatible IDE.
- 3Switch between IEC, Allen-Bradley (RSLogix-style), and Siemens (TIA Portal-style) dialects from the toolbar — without rewriting your logic.
- 4Run auto-graded tests that evaluate sequencing, timing, interlocks, and edge cases against a scripted test harness.
- 5Inspect the IO table mid-scan — every input address and output coil has a live value you can watch while the program runs.
- 6Export IEC Structured Text to paste into a desktop IDE. AB and Siemens export to native formats is on the roadmap.
- 7Work through 40 machine simulation scenarios, from basic motor control to multi-step batch sequencers and PID loops.
Comparison
Comparing online PLC simulators.
This is an honest comparison, not a marketing table. Every tool listed is real and useful for someone. The question is whether the trade-offs match your situation.
| Tool | Browser-based | Free option | Scenarios | Dialects |
|---|---|---|---|---|
| This simulator | Yes | Yes (free tier) | 40 auto-graded | IEC, AB, Siemens |
| PLC-Fiddle | Yes | Yes | None | IEC only (rung drawing) |
| OpenPLC Editor | No (desktop install) | Yes | None | IEC 61131-3 |
| PLCSIM (Siemens) | No (TIA Portal required) | No | Custom only | Siemens STL/SCL |
| Studio 5000 Logix Emulate | No (Windows only) | No | Custom only | Allen-Bradley |
| Emulate3D / RoboPlan | No | No | Industrial-scale custom | Vendor-specific |
Desktop tools like OpenPLC Editor and PLCSIM are excellent and worth learning on real hardware. This simulator is the right choice when you cannot or should not install software on the device in front of you — or when you need auto-graded practice scenarios that desktop tools do not ship.
Getting started
How to get started with the online PLC simulator.
Four steps. The first one does not require an account.
1
Open the simulator
Click Open the simulator on this page. No download — it runs in any browser tab. Create a free account (no credit card) and the editor loads within seconds on any broadband connection.
2
Pick a scenario
Choose from the sidebar. Free users have two scenarios: Traffic Light and Motor Start/Stop. Both are complete, graded exercises — not demos. The full 40-scenario library unlocks with a Pro plan.
3
Write your ladder logic or Structured Text
The Monaco editor is the same engine that powers VS Code. It autocompletes instruction mnemonics, flags syntax errors inline, and lets you switch between IEC, Allen-Bradley, and Siemens dialects from the toolbar.
4
Hit Run. Watch the test harness grade your code.
The Phaser-rendered machine responds to your logic in real time. When you trigger the grade, each test case runs — correct sequencing, interlocks, timing windows — and you get pass/fail feedback with failure reasons.
Related simulators
More ways to practise online.
This page covers the zero-install, browser-first angle. If you are looking for a specific capability, these pages go deeper on each topic:
- PLC Simulator — the flagship overview covering all features, all dialects, and all 40 scenarios.
- PLC Programming Simulator — focused on the programming workflow: writing, debugging, and grading ladder logic in the browser.
- Free PLC Simulator — everything you get without paying: two full scenarios, no account required, no trial clock.
- PLC Ladder Logic Simulator — deep dive into ladder logic execution: contacts, coils, timers, counters, and scan-cycle mechanics.
- All 40 scenarios — the full scenario library, indexed by vertical and difficulty, with free-tier flags.
- Structured lessons — the guided curriculum: 18 lessons and 12 quizzes that walk you from your first contact to PID loops, all inside the same online simulator.
Questions
Frequently asked about the online PLC simulator.
Yes. The free tier gives you two complete scenarios — Traffic Light and Motor Start/Stop — with no credit card and no trial timer. You can open the simulator without creating an account by going directly to /scenarios/traffic-light.
Open the online simulator. No install required.
Two complete free scenarios. No credit card. Works on any browser, any device — Chromebook included.
Related: PLC simulator · free PLC simulator · ladder logic simulator