Looking for a PLC sim? Here is a free alternative that runs in any browser — no Siemens license, no install, no Windows requirement. Nine learning dialects and 140 published scenarios.
This is recorded from the working simulator—not a conceptual mockup. See the editor, live I/O and industrial scenario respond together before you create an account.
Write ladder or structured text, run the scan, toggle live I/O and see the machine state respond.
Practice motors, tanks, conveyors, alarms and interlocks instead of watching a decorative animation.
Use checks, explanations and structured learning paths to move from a first rung to job-relevant control work.
No install. No card. Start with a working circuit.
Live PLC sim. No install. No license key.
When most engineers type “PLC Sim” into a search bar, they are often thinking of Siemens PLCSIM — the proprietary software simulator that ships with TIA Portal. PLCSIM is a solid tool: it runs actual S7-1200 and S7-1500 firmware in a virtualised environment, integrates with the TIA Portal IDE, and supports Profinet and OPC UA communications. For a Siemens-shop controls engineer on a licensed Windows workstation, it is the right choice. The catch is access friction: TIA Portal licenses start at hundreds of dollars, the installer is several gigabytes, and the whole toolchain is Windows-only. If you are a student on a Mac, a self-learner without a budget for vendor software, or an engineer who wants to sketch a logic change during a flight, that friction matters.
Our platform is a different product with similar intent: a software-only plc simulation environment you can open in any browser tab. It is not Siemens PLCSIM, it does not load Siemens project files, and it is not affiliated with Siemens AG. What it does do is run a real scan-cycle engine against IEC 61131-3, Allen-Bradley-style, and Siemens-style ladder logic and Structured Text — for free, with no install, on any operating system. Think of it as a plcsimulator for practice and learning rather than a hardware-specific commissioning tool.
Four things that make this the practical choice for learners, students, and engineers who do not want install friction.
Open a URL. Write a rung. No TIA Portal, no Windows-only runtime, no gigabyte installer. Works on any machine with a modern browser — Chromebooks included.
Two complete, auto-graded scenarios are free with no account and no credit card. Siemens PLCSIM requires a TIA Portal license that starts in the hundreds of dollars.
Switch between IEC 61131-3 Structured Text, Allen-Bradley RSLogix-style rungs, and Siemens-style networks from the toolbar. Same scenario, same physics, three ways to write the solution.
Every scenario ships with hidden test cases that evaluate your logic for correct sequencing, interlock behaviour, and timing. You get a pass/fail result plus the exact failure reason — not just a blinking light.
Siemens PLCSIM runs real S7 firmware inside a virtualised CPU. That means it accurately emulates bus timing, firmware-specific behaviour, and the exact instruction set of a physical Siemens controller. If you are commissioning a real plant with a Siemens S7-1500, PLCSIM gives you near-hardware fidelity — and that is not something we match.
The right tool depends on what you are doing. For commissioning a real Siemens installation, use PLCSIM. For learning PLC logic, practicing for interviews, or testing control patterns without hardware, this plc sim is the faster, cheaper path.
Start with the no-account Try lab, then use a free account to save progress. Each scenario is a full machine model with an IO list, a written objective, and a scripted test suite. The library has 140 published scenarios.
Four-way signal with timer chain and all-red safety interlock phase.
Three-wire control with seal-in, E-stop, and thermal overload interlock.
Photo-eye sort station with part counters and reject actuator output.
Level sensors with hysteresis control and latched high-level alarm.
Closed-loop temperature control with tunable PID and setpoint ramp.
Multi-step sequencer with ingredient timing and agitator interlock.
Showing 6 of 140 published scenarios. View all 140 →
Run the first program without an account, then get 27 free scenarios — or open the Traffic Light scenario right now without an account.
PLCSIM and TIA Portal are registered trademarks of Siemens AG. This site is not affiliated with or endorsed by Siemens AG.