PLC Simulator Online
Learning Ladder Logic was never easier than now!
A free, browser-based Ladder Logic simulator for learning PLC programming — used by 250,000+ students, hobbyists, and engineers every year.
Looking for more? Try rungs.dev, our new AI-assisted simulator with Ladder Logic, Structured Text, and a full tag database — modeled on Allen-Bradley's Logix Designer®.
Code
Start coding instantly with just your browser, using our user-friendly application available on both PC and mobile devices. We strive to provide the most straightforward PLC programming experience. Refer to our documentation for a deeper understanding of Ladder Logic.
Simulate
Gone are the days of needing a real PLC to test your code. With our simulator, you can bypass the need for physical controller. Once your ladder diagram is set, hit the Simulate button to execute your program. You can alter input states and monitor outputs seamlessly.
Share it!
At the heart of PLC Simulator lies the ability to share your diagrams. Simply save your code and get a shareable link. Put your ladder logic online for feedback or share your solutions as a teaching aid. Our platform fosters a collaborative learning environment for all.
Join users from 190+ countries
Students, hobbyists, and engineers worldwide use PLC Simulator Online to learn Ladder Logic, save diagrams, and share their work.
- 25k+
- registered users
- 95k+
- saved projects
- 1.5k+
- users daily
Roadmap
From a small learning tool in 2020 to a community-maintained open-source project today — and the next chapter for learning PLC programming in Rungs. Join our Discord server to share your ideas and follow the journey.
Basic ladder elements
Implementation of the fundamental building blocks of Ladder Logic, introducing the use of basic elements such as contacts, coils, and branches to allow users to create basic PLC programs.
Version 1.0.0 release
Following the initial launch, the 1.0.0 version introduced significant enhancements including adding remaining Ladder Logic functions, saving and sharing diagram functionalities, and converting the platform to a Progressive Web Application for improved accessibility.
UI redesign, drag&drop for desktop
Introduced a user interface redesign to visually display input and output values on ladder blocks, improving clarity. Also added a drag-and-drop feature for a more interactive desktop experience.
Documentation website
Launched a comprehensive documentation website to assist users with Ladder Logic concepts and platform features.
PLC Simulator Online goes open-source
The simulator's source code was released to the community under an open-source license, inviting developers worldwide to contribute. Read the announcement or visit the GitHub repository.
Rungs — a new way to learn PLC programming
A modern browser PLC simulator built from scratch, with both visual ladder and structured-text editors, support for BOOL/DINT/REAL/array tags, real-time simulation, an integrated test runner, and Relay — an AI assistant that reads your code as you build. Try it at rungs.dev.
Meet rungs.dev — learn PLC programming with AI assistance
A browser-based Ladder Logic and Structured Text simulator modeled on Rockwell's Studio 5000 Logix Designer® — tag types, instruction names, expression evaluation, and program structure follow its conventions, so concepts you learn in Rungs transfer directly to industry tools.
Visual and text-based editors
Visual Ladder Logic editor with XIC, XIO, OTE, timers, and counters — plus a full Structured Text editor supporting IF/THEN, CASE, FOR, and WHILE.
Relay AI assistant
An AI assistant that reads your code as you build. Explains behavior, surfaces compiler warnings, and suggests next steps in context.
Tags, trends & tests
Full tag database for BOOL, DINT, REAL and arrays. Trend charts for tag values over time. Automated test runner for Add-On Instructions.
Rockwell Automation, Allen-Bradley, Logix Designer, and Studio 5000 are trademarks or registered trademarks of Rockwell Automation, Inc. rungs.dev is not affiliated with, authorized, or endorsed by Rockwell Automation.
