Free PLC Simulators Compared: PLCSIM, CCW, CODESYS, OpenPLC and Browser Simulators

The best free PLC simulator depends on the brand you want to work with. For Allen-Bradley, use Connected Components Workbench with its Micro800 Simulator. For vendor-neutral IEC 61131-3 skills, use CODESYS. For zero cost with real hardware later, use OpenPLC. For Siemens, use the time-limited TIA Portal trial with PLCSIM. Browser simulators suit a first afternoon.

Checked 26 September 2026 on each maker's own page, or its named distributor's where stated. Terms change, so read the download page before you plan a course around a trial.

What a PLC simulator does, and what it does not

A PLC simulator runs your program on your computer instead of on a controller. You write the logic, download it to the simulated PLC, switch it to run, and change inputs by hand to see what the outputs do. For learning the language, the scan cycle, timers, counters and program structure, that is everything you need.

What a simulator cannot teach is the physical side: wiring a sinking sensor, finding a blown fuse on an output card, or going online to a real controller over a network. Those come later, on a trainer or on the job. The honest way to use a simulator is to learn the logic until it is second nature, so that when you do stand in front of a panel, the only new things are the wires.

There are two families. Vendor simulators (PLCSIM, the Micro800 Simulator, XG-SIM) behave like one maker's controllers and use that maker's editor, so what you learn transfers directly to the job. Neutral or browser simulators (CODESYS, OpenPLC, rungs.dev, PLCPractice) teach the ideas that every PLC shares, with less to install.

The comparison

Siemens: S7-PLCSIM inside the TIA Portal trial

Siemens does not sell PLCSIM as a free tool, but it does publish a trial download of STEP 7 (TIA Portal) on Siemens Industry Online Support that bundles STEP 7, STEP 7 Safety, S7-PLCSIM and WinCC. The trial licence is time-limited, so the sensible approach is to prepare first: read the course notes, plan your practice tasks, and install the trial when you are ready to work through them in a few focused weeks.

If Siemens is the brand in the job adverts near you, it is worth that effort. Our Siemens TIA Portal course is built around the trial and PLCSIM, and the Siemens engineer path takes you further once you are comfortable.

Rockwell: Connected Components Workbench and the Micro800 Simulator

Rockwell Automation's Connected Components Workbench (CCW) comes in two editions. The Standard Edition is free from Rockwell's Product Compatibility and Download Center, and Rockwell says it includes a demo version of the Micro800 Simulator. The paid Developer Edition adds the full Micro800 Simulator and more programming features. CCW programs the Micro800 family (Micro820, Micro850, Micro870) in ladder, function block diagram and structured text.

For a beginner this is the easiest vendor route: free, reasonably light, and close to the way Rockwell's larger software works. Our Micro800 with CCW course starts with the install and a one-rung program in the simulator.

CODESYS: a free IDE and a two-hour soft PLC

The CODESYS Development System is listed at €0.00 in the CODESYS Store, and its setup includes a demo version of the soft PLC CODESYS Control Win SL. CODESYS's data sheet is clear about the limit: in demo mode the soft PLC runs for two hours without a licence, then needs a manual restart. For study sessions that is rarely a problem.

What makes CODESYS worth learning is that many controller makers build on it, so the skills carry over. ABB, for example, says its Automation Builder is built on CODESYS. We cover this in more depth in CODESYS for free and the IEC 61131 and software PLCs path.

OpenPLC: open source, with a simulator and real boards

OpenPLC is open-source PLC software. Its maintainers describe it as free to use, modify and distribute, and say it runs on Windows, macOS, Linux, Raspberry Pi and Arduino. The OpenPLC Editor is a desktop application under the GPL-3.0 licence, and its board list includes an OpenPLC Simulator target, so you can test a program with nothing plugged in. The languages are ladder, structured text, function block diagram and instruction list.

The appeal is the next step: the same program can go onto an Arduino, an ESP32 or a Raspberry Pi. See OpenPLC on Arduino, ESP32 and Raspberry Pi.

Beckhoff TwinCAT 3 and LS Electric XG5000

Beckhoff says the core of TwinCAT 3 Engineering (PLC programming) is free and can be installed on any number of development computers. Runtime functions use trial licences that last seven days and can be generated again any number of times. It suits learners heading for PC-based control and structured text. Our TwinCAT 3 course is intermediate level.

For LS Electric, AutomationDirect (which sells LS Electric PLCs in North America) says XG5000 is 100% free with no licence or key needed, and that XG-SIM is a Windows-based virtual PLC for running and debugging a program without hardware. Our LS Electric XGB course uses it.

Two more makers offer free entry points worth knowing: Schneider Electric lists EcoStruxure Machine Expert Basic for M221 controllers as a free download, and ABB offers a free Basic licence for Automation Builder.

PLC simulator online: rungs.dev and PLCPractice

If you want to try ladder logic in the next ten minutes, a browser simulator is the fastest start.

• rungs.dev runs ladder logic and structured text in the browser, with instructions such as XIC, XIO and OTE, timers and counters, a step-one-scan control and a test runner. Its pricing page says the first eight exercises are free with no account needed; a paid Plus plan opens the rest of the catalogue.
• PLCPractice describes itself as interactive ladder logic lessons, guided practice problems and a free browser-based PLC simulator.

Use them to get comfortable with contacts, coils and the scan. Then move to a vendor tool, because that is what an employer will ask about.

How to choose

A simple rule: pick the brand first, then the simulator that comes with it. If no brand dominates where you want to work, start with CODESYS or OpenPLC for the IEC ideas and add a vendor tool once you know which one you need.

What to practise, whichever simulator you pick

The exercises that build real skill are the same on every simulator. Work through them in this order and do not move on until each one behaves exactly as you expect:

1. A start/stop circuit with a seal-in, and a second version using set and reset.
2. An on-delay timer that starts a second motor five seconds after the first.
3. A counter that stops a conveyor after ten boxes, with a reset button.
4. A two-way traffic light, written first with timers, then as a sequence.
5. An analog input scaled from raw counts to engineering units, with a high alarm.
6. The same start/stop wrapped in a function block and used for three motors.

If your simulator lets you step one scan at a time, as rungs.dev and most vendor tools do, use it on exercise 1. Watching the seal-in contact go true one scan after the coil is the moment the scan cycle stops being theory.

PLC simulator free download: stay on the maker's site

Download simulators only from the maker's own site or its official distributor. Search results for "free download" often lead to third-party sites offering repackaged installers or licence cracks. Beyond the legal problem, an engineering laptop that later connects to a live plant network is the last place for software of unknown origin.

Learn on a simulator with a free course

Every EDWartens course runs in vendor free or trial software with a simulator, so no hardware is needed. Learning is free in full: video lessons by independent YouTube creators, credited on every course page, with written notes, a practice task per module and one final assessment of 15 questions (60% to pass). Start with CODESYS and IEC 61131-3, OpenPLC or Micro800 with CCW, or browse all free PLC training.

The only paid item is optional: an EDWartens Certificate of Completion after you pass. For a beginner course it is a small one-off fee, from US$2.99, and checkout shows your price. Anyone can check it at edwartens.com/verification. It is not a Siemens, Rockwell or CODESYS certification, and it is not accredited or a university qualification.

Take the free course

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CODESYS and IEC 61131-3 Programming

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OpenPLC: IEC 61131-3 on Arduino, ESP32 and Raspberry Pi

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Allen-Bradley Micro800 with Connected Components Workbench

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Siemens TIA Portal