PLC Simulator
Free for students

PLC Simulator for Students

Practice real IEC 61131-3 ladder logic in your browser. Auto-graded machine scenarios, structured lessons, and interview preparation — no install, no credit card.

Join 15100+ learners practicing PLC programming

Create a free account to track progress. No card and no trial clock.

Why students choose us

Everything you need. Zero hardware cost.

Real IEC 61131-3 execution

Your ladder logic runs through a real parser and interpreter — not a visualization. The same IEC standard used in Codesys, OpenPLC, and hundreds of industrial controllers.

Auto-graded feedback

Authored scenarios use repeatable test cases. Submit your program and get objective, immediate feedback about the required machine behavior — no need to grade your own diagram.

Structured curriculum

55 learning modules, 12 quizzes, 6 interview tracks, and curated Beginner, Intermediate and Advanced paths take you from PLC fundamentals to job-ready plant control.

The concepts you'll learn

A visual map of the PLC fundamentals

The guided paths build these concepts in prerequisite order — scan cycle, ladder logic, wiring, timers, counters, Structured Text, safety, process control and diagnosis. Every pattern becomes something you write, run and grade in the browser. No hardware or install.

PLC architecture for students — CPU, input modules, output modules and field devices — the first concept in the free PLC curriculumA modular PLC rack on a backplane: power supply, CPU processor, input module, output module and a communications module side by side.PLC RACKbackplane busPSUPowerCPUProcessorDIInputDOOutputNETComms
Lesson 1 — what a PLC is: CPU, inputs, outputs, and the field devices they connect to.
The PLC scan cycle for students — read inputs, execute the program, update outputs, then repeat — taught early in the free browser PLC curriculumThe repeating PLC scan cycle: read inputs, execute the ladder logic, update outputs, then housekeeping, looping continuously.1Read Inputs2Execute Logic3Update Outputs4HousekeepingSCANCYCLE
The scan cycle — the single idea that makes ladder logic make sense.
A student's first ladder logic rung — a normally-open contact driving an output coil — written and auto-graded in the browser PLC simulatorA basic ladder logic rung between two power rails: an examine-if-closed contact (XIC) in series driving an output coil (OTE).L1L2] [StartXIC I:0/0LampOTE O:0/0
Your first rung — a contact driving a coil — graded instantly in the browser.
Ladder logic symbols for students — normally-open and normally-closed contacts, output coils, set and reset coils — the alphabet of PLC programmingThe core ladder logic symbols side by side: XIC examine-if-closed, XIO examine-if-open, OTE output energize, OTL output latch and OTU output unlatch.XICIfXIOIfOTEEnergizeLOTLLatchUOTUUnlatch
The ladder symbol set — the alphabet you read and write across every scenario.
An IEC TON on-delay timer timing chart for students, the instruction behind the traffic-light scenario in the free PLC curriculumA TON on-delay timer: the accumulated time bar ramps up toward the preset value, and the done (DN) bit turns on when the accumulator reaches preset.TONPRE 5000ACCACC ramps to PREPREDNdone bit
Timers (TON / TOF) — the instruction behind the traffic-light scenario.
An IEC CTU up-counter for students, the instruction used to count parts in the conveyor-sort scenario of the free PLC curriculumA CTU count-up counter: each input pulse increments the accumulator toward the preset, and the done (DN) bit turns on when count reaches preset.count pulsesCTUPRE 5ACC 3ACCcount toward presetDNdone bit
Counters (CTU / CTD) — the instruction used to count parts in conveyor scenarios.
The five IEC 61131-3 languages for students — Ladder, Function Block, Structured Text, SFC and Instruction List — the standard taught in the free PLC curriculumThe five IEC 61131-3 PLC programming languages as chips: Ladder Diagram, Function Block Diagram, Structured Text, Instruction List and Sequential Function Chart.IEC 61131-3 — five languagesLDLadder DiagramFBDFunction BlockSTStructured TextILInstruction ListSFCSequential Func. Chart
IEC 61131-3 — the international standard, so the skills transfer to Codesys, OpenPLC and real controllers.
An IEC 61131-3 Structured Text code block for students, the text-based PLC language introduced later in the free curriculum for state machines and PIDA small Structured Text code block in an editor: an IF/THEN condition, a TON timer call and assignments, showing text-based PLC programming.main.st — Structured Text1IF Start AND NOT Stop THEN2 Run := TRUE;3END_IF;4DelayTmr(IN := Run, PT := T#5s);5Lamp := DelayTmr.Q;
Structured Text — the high-level language for state machines and PID, introduced later in the path.

Follow it all in My Learning Path, or explore the browser PLC simulator directly.

Practice scenarios

From traffic lights to industrial machines

170 published scenarios across industrial domains. Each has a detailed brief, animated simulation, and auto-graded test cases.

Beginner

Traffic Light

Three-phase timer sequence. Classic first PLC project.

View scenario →
Beginner

Motor Start/Stop

Seal-in rung, stop button, overload protection.

View scenario →
Intermediate

Tank Fill

Level sensor, inlet valve, pump, overflow alarm.

View scenario →
Advanced

PID Temperature

Closed-loop temperature control with PID tuning.

View scenario →

How it works

Four steps to your first passing program

01

Sign up free

Create your account in 30 seconds. No credit card or trial clock. The source catalog tags 32 practice records for free-tier access; visibility can vary by entitlement and rollout.

02

Start the curriculum

Follow curated Beginner, Intermediate and Advanced paths from PLC fundamentals to PID and plant-scale control, or explore any scenario.

03

Write real programs

Type ladder logic or structured text in the code editor. Run it against the machine simulation and watch outputs respond in real time.

04

Get graded feedback

Submit your program and the auto-grader runs every test case. See exactly which steps passed and which failed.

Why us

vs OpenPLC, LogixPro, and PLC-Fiddle

No install — works on any browser, any OS, any device
Auto-graded scenarios give objective pass/fail feedback
Curated Beginner–Advanced paths vs no guided progression
Three vendor dialects: IEC, Allen-Bradley, Siemens
Interview tracks with hands-on coding rounds
Free forever tier — not a 30-day trial

Pricing

Start free. Go pro when you are ready.

The free tier gives you 32 practice scenarios, guided beginner labs and starter learning modules — enough to build real foundations. Pro adds all 170 published scenarios, 55 modules, 108 dialect lessons, 12 quizzes and 6 interview tracks.

For classes and engineering teams

Assign this training to a managed cohort

Import a roster, assign learning paths, export learner progress and issue organisation-attributed certificates. Test it with a real cohort before purchasing.

Questions

Student FAQ

Yes. Run a guided first program without an account, then create a free account for 32 practice scenarios, including 10 guided beginner PLC labs. There is no card or time limit. Pro unlocks all 170 published scenarios when you are ready.

Start learning PLC programming today

Free tier. No install. No credit card. 30-second signup.

Create free account →

Competency and practice field guide

PLC simulator for students: practice plan

Direct answer

The learner can build, run, diagnose and explain a small machine program and preserve evidence for instructor or portfolio review.

Written for school, college, apprenticeship and self-directed learners needing repeatable PLC practice on their own devices.

Adult learners and an instructor using PLC racks and laptops while studying accessible student PLC programming practice in an industrial automation lab
System map / 02

NODE 01observable

Scope

Learner level, course outcome, device, browser, accessibility, account policy, dialect, practice time and evidence expectation.

NODE 02observable

Signal path

Briefing through executable logic, typed I/O, machine behavior, checks, hints, saved progress and instructor review.

NODE 03observable

Baseline practice

One start-stop, timer and sequence task completed independently from a clean state.

NODE 04observable

Edge cases

Copying, hidden state, weak feedback, inaccessible control, unsupported browser, lost work and missing target transfer.

NODE 05observable

Fault practice

A concept, syntax, runtime, machine, accessibility, persistence, assessment or transfer gap.

NODE 06observable

Transfer to the job

The evidence varied, explained and later recreated in vendor tools and supervised hardware practice.