A virtual PLC lab is a browser tool that gives you a PLC engine, a simulated machine and a way to test your program, so you can practise PLC programming without owning any hardware. It teaches logic, timing, sequences and testing very well. It cannot teach crimping, cable routing or electrical noise. This guide says where that line falls and shows how EDWartens Lab, our own virtual PLC lab, works.
What is a virtual PLC lab?
A PLC runs a program in a repeating scan: read inputs, solve the logic, write outputs. A virtual PLC lab reproduces that loop in software. You write ladder logic, Structured Text or a sequential function chart, press run, and a simulated machine reacts: a motor starts, a tank fills, a conveyor stops at a sensor.
Three parts make a lab rather than a bare simulator:
- A PLC engine that scans your program and keeps its memory.
- A simulated plant, such as a conveyor, a pump or a crossing, wired to the engine's inputs and outputs.
- A test that tells you whether the machine does what the brief asked.
Without the third part you only have a sandbox. You can run anything, but nothing tells you if it is right. Our guide to free PLC simulator software compared lists the sandboxes that exist, and the explainer on PLC scan cycles shows what each of them is simulating underneath.
What a virtual PLC lab does well
Most of what a junior controls engineer does first is logic work, and logic is exactly what software reproduces faithfully.
Logic and sequences. Start/stop circuits with a seal-in, interlocks, timers, counters and step sequences behave the same on a simulated engine as on a real controller. If you are new to this, our video lesson on start/stop ladder logic is the right first stop.
Fast feedback. On hardware, a wrong output can mean a blown fuse or a tripped breaker. In a lab you reset in one click and try again. That makes you try more variations, which is how people actually get good.
Testing against a specification. Real commissioning means proving the machine meets a brief. A lab that ends every job with a numbered test teaches that habit from day one, which is the habit most self-taught programmers lack.
Any time, anywhere. A browser lab needs no licence server, no install and no spare desk. That matters when the alternative is waiting for access to a training room.
What a virtual PLC lab cannot teach
Be honest about this before you list simulator hours on a CV.
| Gap | Why a simulator cannot cover it |
|---|---|
| Crimp and termination quality | There is no wire, ferrule or torque to get wrong in your hands |
| Cable routing and segregation | Nothing in the software gets damaged by bad routing |
| Electrical noise | A simulated signal is clean; a real analogue input is not |
| Real sensor behaviour | Real sensors drift, bounce and fail in ways a model only approximates |
| Real hazards | A mistake costs you nothing, so your instincts are not tested |
| Vendor software | A lab with its own engine does not teach a vendor's project tree and menus |
That last row matters. A vendor's own simulator teaches that vendor's tools, which is useful if your employer uses them; the video below shows the Siemens TIA Portal route. A lab with its own engine teaches the logic that transfers between vendors. Most learners benefit from both, in that order.
Three ways to practise, compared
| Option | Best for | Main limit |
|---|---|---|
| Browser lab with its own engine | Logic, sequences, testing, any device | Not a vendor's software |
| Vendor simulator on your computer | Learning one vendor's tools | Install, licence and a steep menu tree |
| Real hardware kit | Wiring, I/O and real signals | Cost, space and the risk of damage |
Most people end up using more than one. Start where the cost of a mistake is lowest, which is the browser, and move to hardware when your job or your course asks for it.
How EDWartens Lab works
The video above is by Instrumentation Tools and shows PLC simulation inside Siemens TIA Portal. It is a different route from our lab, and a useful one to compare.
EDWartens Lab is free with a free EDWartens account. It runs in the browser, needs nothing to install, works offline once it has loaded, and is best on a laptop though it also works on a phone. You will find it at lab.edwartens.com, and each machine has a public page under /project-sim.
The PLC lab has eight machines: motor start/stop with overload, a forward/reverse conveyor, a star-delta fan starter, a batch counter on a packing line, a tank filling pump, a pedestrian crossing, a parcel sorter, and duty and standby pumps. You program in ladder, Structured Text or SFC, three of the languages in IEC 61131-3, whose fourth edition was published on 22 May 2025. The engine is the lab's own, with familiar Siemens-style addressing. It is not a vendor PLC, and we say so because it affects what carries over: the logic does, the vendor menus do not.
The machine responds in 2D and in 3D. In 3D you stand in a factory hall with the machine and a control cabinet beside it, and you can click parts. That is not decoration. Seeing a sorter gate swing the wrong way is a faster lesson than reading a bit address. It also shows why the 2D view is not enough on its own: in 3D you notice where the sensor actually sits and what the machine does between your commands.
Every job ends in a numbered factory acceptance test, or FAT, that runs automatically. You read a work order, write the program, run it, and the test steps tick off or fail in sequence. When you pass, you can download the FAT report as a PDF. A paid review and signature by a Wartens engineer is available if you want one. The companies in the work orders are fictional.
Beyond the PLC: the Panel Lab
The lab also has a Panel Lab with ten levels at 415 V 50 Hz to IEC practice, where you lock out, prove dead, wire a panel from its schematic and fault-find with a meter. We cover that side in our guides to the control panel wiring simulator and to safe isolation.
How to use a virtual lab so it builds real skill
A lab only helps if you use it like a workshop. These habits make the difference.
- Read the brief before you type. Write down each input, output and condition first. Then write the logic.
- Predict, then run. Say what the machine will do before you press run. Wrong predictions teach the most.
- Break it on purpose. Remove a sensor input, stick a contact, and see what your program does. Real machines fail that way.
- Pass the test, then improve the program. A passing program that you cannot explain is not yet a skill.
- Keep evidence. Screenshots, the FAT report and short notes on what you fixed make a portfolio. Our post on an engineering portfolio from course projects shows how to present them.
NACE, the US association for careers and employers, says a genuine internship has a written position description, learning goals and qualified supervision with feedback. A lab gives you the work and the test. The feedback is the part you add, from a mentor, a teacher or the review of a peer.
Where the lab fits with the free internship and the free courses
The lab is optional practice inside our Free PLC Programming Internship. The internship is free to join, fully online and works from any country. It has eight weeks of short lesson cards, weekly checks and a final quiz, and the lab is one of the places you can practise what the lessons teach. It is training, not employment, and pays no stipend.
For structured study first, the free course on Siemens TIA Portal with Factory I/O virtual commissioning covers the vendor-simulation route, CODESYS and IEC 61131 covers a vendor-neutral programming environment, and OpenPLC with Arduino and Raspberry Pi shows an open-source soft PLC you can run on cheap hardware. Every course is free in full. An optional certificate of completion is a paid extra, and anyone can check it at edwartens.com/verification. For the wider picture of the trade, start with what PLC programming is.
Other providers publish free material too. AutomationDirect offers free PLC training videos for its own controllers, and some vendors sell browser simulators with free tiers; those are the vendors' own claims, so test them yourself before relying on them.
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Questions
What is a virtual PLC lab?
A virtual PLC lab is software that gives you a PLC program editor, a PLC engine that runs it and a simulated machine or process to control, usually in a browser. You write logic, run it, watch the simulated machine respond and fix mistakes, without buying or wiring any hardware.
Can I practise PLC programming online without a PLC?
Yes. A browser simulator runs your ladder or Structured Text program against a simulated machine, so you can learn scan behaviour, timers, counters and sequences with no hardware. It will not teach wiring quality or electrical noise, so add a real kit later if your job needs it.
Is a PLC simulator as good as real hardware?
For logic, timing and testing against a specification it is close, and it is faster because you can reset a fault in a click. It cannot teach crimp quality, cable routing, real sensor noise or real hazards. Treat it as the first stage of practice, not the last.
Is there a free online PLC lab?
Yes. EDWartens Lab is free with a free EDWartens account, runs in the browser with nothing to install and works offline once loaded. Some other providers offer free tiers, and AutomationDirect offers free PLC training videos, though videos are not a lab you can run.
Which PLC languages can I practise in a browser?
In EDWartens Lab you can program in ladder, Structured Text or SFC, three of the languages defined by IEC 61131-3. The lab uses its own PLC engine with familiar Siemens-style addressing, so the logic skills carry over but the vendor software itself does not.
Do virtual labs count as PLC experience on a CV?
They count as practice, not as paid experience. Say plainly that the work was simulated, name the machine and the test you passed, and keep your FAT report or screenshots in a portfolio. Employers value honest, specific evidence more than a vague claim of lab experience.
Sources
- IEC: IEC 61131-3, Programmable controllers, Part 3: Programming languages, 4th edition (published 22 May 2025) (read 16 October 2026)
- AutomationDirect: Free PLC training videos (read 16 October 2026)
- NACE: Internships, definition and criteria (read 16 October 2026)
- 24-7 Press Release: browser-based PLC simulation with HMI, robotics and 3D labs, vendor announcement (read 16 October 2026)
Written by the EDWartens engineering team for general education. Product names are trademarks of their owners; mentioning them does not imply endorsement. Prices and terms of other providers were checked on the date shown and can change.
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