Online PLC simulatorfor Siemens and Rockwell
Write PLC code in your browser and watch a working 3D pump, tank or filling line do exactly what you told it. Every 20 milliseconds the simulator reads the inputs, runs your programme and writes the outputs, just like a real controller.
Nothing to download, no licence and no account. Your work saves on this device.
#PumpOn := (#Start OR #PumpOn) AND NOT #Stop;Press Start once and the pump keeps running. PumpOn holds itself on until Stop breaks the line. PumpOn is FALSE now.
Write it yourself: mission 04, Make it stay runningA full PLC simulator, not an animation
Write real PLC code
8 editor styles: SCL, LAD, FBD and GRAPH for Siemens, and Structured Text, Ladder, FBD and SFC for Rockwell. Text editors check your syntax.
Control working 3D equipment
25 rigs: a pump skid, a mixing vessel, a filling line, two linked tanks and a heat-and-cool vessel. They only move when your code tells them to.
Run, pause and step
Run your programme, freeze the whole plant, or step one 20 millisecond scan at a time and watch every tag change.
Prove it with automatic tests
Each exercise checks your code in several situations. If a test fails, replay it scan by scan to see exactly why.
Find faults like a site engineer
Valves stick, sensors drift and pumps trip. 7 missions start from an operator’s report and ask you to fix the code.
Take your code to the real software
Export Siemens SCL for TIA Portal, or Rockwell Structured Text and ladder for Studio 5000.
Both vendors, eight editor styles
Siemens
- SCLStructured Control Language: written instructions such as #PumpOn := #Start AND NOT #Stop; Good for maths, states and loops.
- LADLadder diagram. Rungs of contacts and coils, read like the relay logic electricians know.
- FBDFunction block diagram. Signals wired through blocks such as timers, comparisons and scaling.
- GRAPHSequences drawn as steps and transitions, for batches and machines that run in phases.
Allen-Bradley
- Structured TextWritten instructions such as PumpOn := Start AND NOT Stop; Good for maths, states and loops.
- LadderLadder logic. Rungs of contacts and coils, read like the relay logic electricians know.
- FBDFunction block diagram. Signals wired through blocks such as timers, comparisons and scaling.
- SFCSequential function chart: steps and transitions for batches and machines that run in phases.
Pick a language and press Run
- Mission 01 · PLC scan cycleYour first commandMake a pump follow a button.8 min · free
- Mission 15 · function block diagramGive the signal meaningTurn raw sensor counts into a percentage.12 min · free
- Mission 23 · SFC and GRAPH sequenceOne batch, four phasesFill. Mix. Drain. Complete.18 min · free
- Mission 05 · PLC fault-findingStop doesn't stop itFind the path that gets round Stop.12 min · free
A PLC simulator without the usual set-up
| Topic | The usual way | This simulator |
|---|---|---|
| Software | Vendor licences and a Windows PC set up for TIA Portal or Studio 5000. | Open a browser tab. Nothing to install, no licence, no account. |
| Equipment | A training rig, or a spare PLC wired to a few switches on a bench. | 25 working 3D machines: pumps, tanks, valves, heaters, mixers, filling lines and a whole factory. |
| Mistakes | On a live plant, one wrong line can flood a floor or run a pump dry. | The tank overflows on screen. You see exactly why, then press Reset. |
| Seeing what happened | A fault is over in a fraction of a second. | Rewind any failure one 20 millisecond scan at a time. |
| Fault finding | It takes years on site to meet a sticking valve or a drifting sensor. | Faults are built into the plant, ready when you are. |
| Siemens or Rockwell | Most courses teach one or the other. | Both, in eight editor styles, from SCL and LAD to Structured Text and Ladder. |
Frequently asked questions
Is this PLC simulator free?
Yes. Everything is free during the beta, with no account and no card details. At launch the guided labs and the first three course stages stay free for good; the full course becomes part of the Pro plan.
Do I need to download or install anything?
No. The simulator runs in a modern browser on a laptop or desktop. There is no download, no licence and no virtual machine to set up.
Which PLC languages can I use?
Siemens SCL, LAD, FBD and GRAPH in editors styled on TIA Portal V20, and Rockwell Structured Text, Ladder, FBD and SFC in editors styled on Studio 5000 v38.
Can I simulate ladder logic?
Yes. Siemens LAD and Rockwell Ladder both run in the simulator. You build rungs from contacts, coils, timers and counters, and the logic that is carrying power lights up green as it runs.
Is it the same as PLCSIM or Logix Emulate?
No. Siemens PLCSIM and Rockwell’s Logix Emulate simulate a controller for the vendor’s own software, which you install and license. This simulator runs in your browser with its own PLC engine, follows the Siemens and Rockwell instruction rules, and adds 3D equipment and automatic tests to practise against.
Can I take my code into TIA Portal or Studio 5000?
Yes. Siemens SCL exports as an external source file (.scl) for TIA Portal. Rockwell Structured Text and ladder export as an .L5X file for Studio 5000.
Does it work on a phone?
You can try the rig, read lessons and answer checks on a phone. A laptop or desktop gives you more room for code, diagrams and the 3D equipment.
Where is my work saved?
In this browser on this device, as you go. Export a backup from Your progress to keep a copy or move it to another computer.
Try your first exercise now
It takes about 8 minutes. Make a pump follow a button, then pass the automatic tests.
Siemens, SIMATIC and TIA Portal are trademarks of Siemens AG. Allen-Bradley, Rockwell Automation, Studio 5000 and Logix are trademarks of Rockwell Automation, Inc. PLC Gym is independent and is not affiliated with or endorsed by either company.