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PLC programming

CODESYS and IEC 61131-3 Programming

Learn PLC programming in CODESYS using IEC 61131-3: ladder, function blocks, structured text, CFC and SFC, then a visualization.

CODESYS and IEC 61131-3 Programming is a free, self-paced online course from EDWartens for engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation. It has 19 modules and takes about 20.9 hours, with written notes, a practice task per module, a practical project and a final assessment of 15 questions (pass mark 60%). Learning costs nothing and needs only a free account. The optional EDWartens Certificate of Completion, verifiable by code, is a one-off US$23.99 for you; it is not a vendor credential. Updated 1 November 2026.

  • Free
  • Beginner
  • 20.9 hours
  • Self-paced
  • Certificate optional
  • Lab practice in your browser
See what you learn

No card, no trial. The course is free for good. Certificate US$23.99, optional.

Who it is for
Engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation
Jobs
Roles that use this skill: PLC programmer, controls engineer, automation technician and commissioning engineer. No course guarantees a job.
Tools
CODESYS Development System (free from the CODESYS Store) with the soft PLC. Hardware: none. The soft PLC runs every exercise.
Updated
CODESYS and IEC 61131-3 Programming course cover
CODESYS and IEC 61131-3 Programming course cover

After this course you can

By the end you will be able to:

  • Install CODESYS and create a project
  • Write ladder logic with latching, gates, timers and counters
  • Tell functions from function blocks
  • Write structured text with IF, CASE and loops
  • Build CFC and SFC programs and a visualization

Who it is for, and what you need first

Who it is for

Engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation.

Level: Beginner. Beginner to intermediate. Ladder first, then the text and graphical languages.

What you need

Software: CODESYS Development System (free from the CODESYS Store) with the soft PLC.

Hardware: None. The soft PLC runs every exercise.. What to download, and how.

How this course works

  1. Watch the lessons

    Short video lessons, one module at a time, at your own pace.

  2. Read the notes

    Open the Reading tab for the written notes and diagrams of the module.

  3. Practise in the 3D labOptional

    Try the module in the free 3D lab, in your browser.

  4. Check yourself

    Answer the questions to see what stuck before you move on.

  5. Final assessment

    Pass the final once you have been through the modules.

  6. Certificate, if you want oneOptional

    Optional, with a page anyone can use to verify it.

What you learn

19 modules in order, at your own pace. 20.9 hours of video lessons, with written notes and a practice task in each module.

  1. 1CODESYS: What It Is and the First Project34m
  2. 2Contacts, Coils and NO/NC, with lab practice: 40m
  3. 3Logic Gates35m
  4. 4Boolean Expressions to Ladder26m
  5. 5Memory Bits and Latching, with lab practice: 36m
  6. 6Toggle Switches and Solenoids35m
  7. 7Pumps, LEDs and Multi-Output Exercises43m
  8. 8Ladder Instructions in Depth1h 20m
Show the other 11 modules
  1. 9Timers: TON, TOF and TP35m
  2. 10Counters: CTU, CTD and CTUD, with lab practice: 49m
  3. 11Functions versus Function Blocks50m
  4. 12FBD and Structured Text: First Steps31m
  5. 13ST Control Flow: IF, CASE and Loops, with lab practice: 41m
  6. 14ST: Timers, Counters, Edges and Structures31m
  7. 15ST: Functions, Function Blocks and Utilities52m
  8. 16CFC: Continuous Function Chart, with lab practice: 39m
  9. 17SFC: Sequential Function Chart, with lab practice: 1h 2m
  10. 18Visualization, with lab practice: 18m
  11. 19Final Assessment

Software you need

What to download, where from, what it costs and how to install it. Every link goes to the maker's own site, never a mirror.

Factory I/O is optional: two of the FBD and CFC videos drive its 3D scenes, and every exercise also runs in the CODESYS simulator alone.

Show what to download (2 tools)

Required

  1. 01

    CODESYS Development System V3

    CODESYS GmbH

    Free
    Runs on
    Windows 10 or 11, 64-bit (8 GB RAM and 12 GB free disk recommended)
    Account
    A free CODESYS Store account (one-time registration)

    The Development System is free in the CODESYS Store. The setup also installs a demo of the CODESYS Control Win SL SoftPLC, which runs for two hours without a licence and then needs a manual restart.

    Official download pagestore.codesys.com

Optional

Useful, not needed to finish the course.

  1. 02

    Factory I/O

    Real Games

    Free trial: 30 days
    Runs on
    Windows 7 SP1 or newer, with a graphics card from 2006 (NVIDIA, AMD) or 2012 (Intel) onwards
    Account
    Your name and email on the Factory I/O trial form

    The 30-day trial includes the full Ultimate Edition. After that you need a paid edition; the Siemens, Allen-Bradley, Modbus and OPC, MHJ, Automgen and Starter editions each support different PLCs.

    Official download pagefactoryio.com

Checked against each maker's own page on 27 September 2026. Trial lengths and editions change; the maker's page is the final word.

Practise in the 3D lab

Write the same ladder, structured text and SFC you learn in CODESYS on working machines in the PLC lab, which runs all three languages.

Build a ladder rungWatch

Optional. Skip it whenever you like: it never blocks your progress or your certificate.

Course project, about 10 hours

Polyhouse climate and fertigation control in CODESYS: ST, SFC, FBD, retained counts and a visualization

Design, program, test and document the climate and fertigation control of a one-acre rose polyhouse on the CODESYS soft PLC. You write staged cooling and fogging in structured text, a three-zone fertigation cycle as an SFC, and the interlocks in FBD. You add a weather-link watchdog and retained counts, then a screen the owner can read in a browser. You deliver the project, your I/O list, interlock list and FAT record. The sample pack shows what an integrator hands a farm.

This project at a glance
  1. 7documents in the pack
  2. 8steps to follow
  3. 6things to hand in
  4. 10 hof work, at your pace
  • FDSFunctional Design Specification: PH-3 Climate and Fertigation Control
  • I/O listI/O List: Panel PH3-CP1 (PiXtend V2 -L-)
  • BOMBill of Materials: Panel PH3-CP1 and Field Devices
  • Interlock listInterlock and Permissive List: PH-3
  • IP planIP Address Plan and Device List: PH-3 Control Network
  • FATFactory Acceptance Test Record: Panel PH3-CP1

The project is optional practice. The certificate needs only the modules and the final assessment.

After the course, your next step

Show what you can do, then keep going in the same field.

Sample EDWartens Certificate of Completion for CODESYS and IEC 61131-3 Programming

Sample. The issued certificate carries your name, your final score, a certificate ID and a QR code that opens its verification page.

Optional

A certificate you can verify

Finish the modules and pass the final assessment (15 questions, pass mark 60%) and you can add a certificate with a public verification page. One-off, US$23.99 for you. It is not a vendor credential.

Want a free certificate? Do the matching Free internship: 4 weeks, nothing to buy, with a free certificate of completion.

An engineer in a hard hat checking neat, labelled wiring on I/O racks inside an open control cabinet.
Free · 4 weeks · free certificate

PLC Programming

Eight short weeks of PLC ladder logic on free simulators: notes, diagrams, a few videos and auto-tested tasks. Finish weeks 1 to 4 and the final, then claim a free Internship Completion Certificate with your real dates and study hours, and a QR code anyone can scan to verify it. Training, not employment.

See the internship

Part of a learning path

Courses in a planned order, so each one builds on the last.

More free courses

Roles that use this skill

  • PLC programmer
  • Controls engineer
  • Automation technician
  • Commissioning engineer

These are the kinds of roles where the skill is used. We make no promise of a job or an interview.

Plain notes

  • Free: the whole course, the notes, the practice tasks, the final assessment and support from practising engineers.
  • Paid, and optional: the course certificate, and the Engineer-verified internship (the Free internship costs nothing).
  • No job promise: the course teaches a skill. It does not place you in a job.
  • Lessons by: Instrumentation Tools, plcgoods, Tohid Alizadeh, RealPars, Shane Welcher SR. Independent creators; the lessons stream from their own channels. EDWartens wrote the study plan, notes, practice tasks and assessments.

Instrumentation Tools · plcgoods · Tohid Alizadeh · RealPars. If you are one of these creators and want a lesson removed or credited differently, write to info@edwartens.com.

Practise what you learn in the free 3D lab

Technical work is judged on what you can do: wiring, commissioning, finding a fault. Doing a task yourself teaches more than watching it a second time, and a lab lets you try it safely before you meet real equipment. It does not replace working on real hardware.

See the 3D lab
  • Practise safely, so a mistake costs nothing.
  • The lab checks your work like a site test, so you know when it is right.
  • Free, in your browser, with nothing to install.

Why learn with EDWartens

What you get with this course, and what comes after it.

  • Free from the first lesson to the final assessment.
  • Practice in a free 3D lab in your browser, with nothing to install.
  • Video lessons with written notes and a project.
  • An optional certificate that anyone can verify online.
  • Free internships to keep practising afterwards.

Common questions

Is CODESYS free?

Yes. The CODESYS Development System and its soft PLC for testing are free from the CODESYS Store. Runtime licences for real hardware are separate and not needed here.

Which PLC brands use CODESYS?

Schneider Machine Expert, ABB Automation Builder, Beckhoff TwinCAT, WAGO, Festo, Eaton and many more are CODESYS-based, so what you learn here transfers directly.

Do I need Factory I/O?

No. The projects are shown so you can follow the logic; every practice task runs on the soft PLC.

Do I need to know ladder first?

No. The first seven modules teach ladder from scratch before structured text starts.

What computer do I need for the CODESYS and IEC 61131-3 Programming course?

A 64-bit Windows 10 machine with 8 GB of RAM. CODESYS is Windows-only.

Is the CODESYS and IEC 61131-3 Programming course really free?

Yes. Every module, practice task and assessment. You create an account so your progress is saved and the assessments can be marked. The certificate is the only paid item, and only if you want it.

What certificate do I get, and is it a CODESYS GmbH qualification?

An EDWartens Certificate of Completion, issued when you pass the final assessment, with a verification code anyone can check. It is not a CODESYS GmbH credential and is never described as one.

Who made the video lessons in the CODESYS and IEC 61131-3 Programming course?

The creators named in the Credits block at the foot of this page, on their own YouTube channels. EDWartens did not make the videos and the creators are not affiliated with EDWartens. What EDWartens wrote is the study plan, the notes, the practice tasks and the assessments.

Do I have to use the lab?

No. The lab is optional practice. You can skip it whenever you like, and it never blocks your progress, the final assessment or your certificate.

Is the lab free?

Yes. Every lab level for this course opens in your browser, free, with nothing to install.

What topics does the CODESYS and IEC 61131-3 Programming course cover, module by module?

The CODESYS and IEC 61131-3 Programming course has 19 modules. It opens with "CODESYS: What It Is and the First Project", goes through "Contacts, Coils and NO/NC", "Pumps, LEDs and Multi-Output Exercises", "ST Control Flow: IF, CASE and Loops" and "Visualization" and ends with "Final Assessment". The full list with minutes is under "What you learn" on this page.

What can I do after the CODESYS and IEC 61131-3 Programming course?

After the CODESYS and IEC 61131-3 Programming course: Explain why CODESYS sits inside so many PLC brands; Build ladder from NO/NC contacts to gates, latching and exercises; Use the IEC timers and counters and read their pins. These are the practical outcomes the course is written around, and the final assessment of 15 questions checks them.

What software and hardware do I need for the CODESYS and IEC 61131-3 Programming course, and does it cost anything?

For the CODESYS and IEC 61131-3 Programming course, software: CODESYS Development System (free from the CODESYS Store) with the soft PLC. Hardware: none. The soft PLC runs every exercise. The course itself is free.

Is the CODESYS and IEC 61131-3 Programming course suitable for me, and what level is it?

CODESYS and IEC 61131-3 Programming is rated beginner. Beginner to intermediate. Ladder first, then the text and graphical languages. It is written for engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation, and takes about 20.9 hours at your own pace.

Which jobs use the skills from the CODESYS and IEC 61131-3 Programming course?

Skills from the CODESYS and IEC 61131-3 Programming course (for example: explain why CODESYS sits inside so many PLC brands) are used in roles such as PLC programmer, controls engineer, automation technician and commissioning engineer, and in automation engineer work. The course gives you practical evidence of the skill; it does not promise a job, and employers decide on experience and interview.

Start free today

CODESYS and IEC 61131-3 Programming, at your own pace. Add the certificate only if you want one.