PLC programming
Siemens TIA Portal: Organisation Blocks, Interrupts and Timers
See what the S7-1200 and S7-1500 do between your rungs: the cycle, startup, interrupts, error blocks and every timer.
Siemens TIA Portal: Organisation Blocks, Interrupts and Timers is a free, self-paced online course from EDWartens for engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation. It has 8 modules and takes about 6.5 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$28.99 for you; it is not a vendor credential. Updated 1 November 2026.
- Free
- Intermediate
- 6.5 hours
- Self-paced
- Certificate optional
- Lab practice in your browser
No card, no trial. The course is free for good. Certificate US$28.99, 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
- The current TIA Portal trial (21 days) with S7-PLCSIM, on 64-bit Windows 11 Pro or Enterprise; any version from V15 on covers what this course teaches. Hardware: none, everything runs in simulation.
- Updated
After this course you can
By the end you will be able to:
- Explain the cycle and read the cycle time
- Use OB100 for startup work
- Write time-delay, cyclic and hardware interrupt blocks
- Handle errors in OB80, OB82 and OB121
- Use TON, TOF, TP, TONR and clock memory correctly
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: Intermediate. Intermediate. You should already write ladder in TIA Portal.
What you need
Software: The current TIA Portal trial (21 days) with S7-PLCSIM, on 64-bit Windows 11 Pro or Enterprise; any version from V15 on covers what this course teaches.
Hardware: None, everything runs in simulation. What to download, and how.
How this course works
Watch the lessons
Short video lessons, one module at a time, at your own pace.
Read the notes
Open the Reading tab for the written notes and diagrams of the module.
Practise in the 3D labOptional
Try the module in the free 3D lab, in your browser.
Check yourself
Answer the questions to see what stuck before you move on.
Final assessment
Pass the final once you have been through the modules.
Certificate, if you want oneOptional
Optional, with a page anyone can use to verify it.
What you learn
8 modules in order, at your own pace. 6.5 hours of video lessons, with written notes and a practice task in each module.
- 1OB1, the Cycle and Cycle Time; OB100 at Startup18m
- 2Time-Delay Interrupts (OB20) and Cyclic Interrupts (OB30)26m
- 3Hardware Interrupts (OB40): Digital and Analog21m
- 4Error OBs: OB80 Time Error, OB82 Diagnostic Error and OB121 Programming Error56m
- 5System Time, Local Time and Time-of-Day Interrupts (OB10)28m
- 6Timer Types, TON, TOF, TP and TONR, Reset and Preset, with lab practice: 41m
- 7Legacy S7 Timers, Clock Memory and Counting Seconds, with lab practice: 38m
- 8Final 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.
Show what to download (2 tools)
Required
- 01Free trial: 21 days
SIMATIC STEP 7 Professional and WinCC (TIA Portal) V21 Trial
Siemens
- Runs on
- Windows 11 Pro or Enterprise 64-bit (24H2), Windows 10 Enterprise 2021 LTSC, or Windows Server 2022/2025. Windows 11 Home is supported only for the Basic editions.
- Account
- A free Siemens account registered for Industry Online Support (SiePortal)
- Size
- about 8.1 GB for the main ISO, plus an optional 3.1 GB DVD 2 with hardware support packages
Siemens lets registered users download the V21 trial of STEP 7 (Basic and Professional), STEP 7 Safety and WinCC and test it for 21 days. The same package is used for the full product; after 21 days you need a purchased licence to keep working.
Steps
- 1.Open the Siemens trial page (entry 109989774) and sign in with your Siemens Industry Online Support account.
- 2.Download TIA_Portal_STEP7_Safety_WinCC_V21.iso (8.1 GB).
- 3.Download S7-PLCSIM_V21.iso (2.5 GB) from the same page: PLCSIM is a separate download.
- 4.Right-click each ISO, choose Mount, and run Start.exe as administrator. Install STEP 7 and WinCC first, then PLCSIM.
- 5.Follow the setup, accept the licence terms and restart the PC when asked.
- 6.Open TIA Portal V21 and create a new project to confirm it runs.
- Install from a local drive with plenty of free space; Siemens lists 20 GB free as the minimum and the ISOs alone are over 10 GB.
- You only need DVD 2 if you want extra hardware support packages.
- If you cannot install locally, Siemens also offers a 21-day TIA Portal Cloud trial in the browser (one-hour sessions, not in every country).
Official download pagesupport.industry.siemens.comAlternatives
- TIA Portal Cloud trial: 21 days free in a cloud virtual machine, no install. Sessions are limited to one hour and it is not available in every country.
- 02Free trial: 21 days
S7-PLCSIM V21 (TIA Portal) Trial
Siemens
- Runs on
- Windows 11 Pro or Enterprise 64-bit (24H2), Windows 10 Enterprise 2021 LTSC, or Windows Server 2022/2025. Windows 11 Home is supported only for the Basic editions.
- Account
- A free Siemens account registered for Industry Online Support (SiePortal)
- Size
- about 2.5 GB (ISO)
S7-PLCSIM V21 is offered as a 21-day trial on the same Siemens page as the STEP 7 and WinCC V21 trial. It needs STEP 7 V21 installed on the same PC.
Steps
- 1.Open the Siemens STEP 7 and WinCC V21 trial page (entry 109989774) and sign in.
- 2.Install STEP 7 V21 from the main TIA Portal ISO first.
- 3.Download S7-PLCSIM_V21.iso (2.5 GB) from the section Download S7-PLCSIM Standard V21.
- 4.Mount the ISO, run Start.exe as administrator and follow the setup.
- 5.In TIA Portal, select your CPU and click Start simulation to open PLCSIM.
- Siemens notes that the PLCSIM Standard V21 installation also includes S7-PLCSIM Advanced V8.0.
Official download pagesupport.industry.siemens.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
Practise the timer types and timed sequences from this course on working machines in the PLC lab, and see how a delay changes what a machine does.
- Pedestrian crossingPLC lab, about 75 minOpen in the lab (opens in a new tab): Pedestrian crossing
- Star-delta fan starterPLC lab, about 60 minOpen in the lab (opens in a new tab): Star-delta fan starter
Optional. Skip it whenever you like: it never blocks your progress or your certificate.
Course project, about 16 hours
Stamping press production control: stroke counting in OB40, cushion watch in OB30, shift changeover in OB10
Program and prove the production control for a 250-tonne stamping press on a simulated S7-1500. It counts every stroke in a hardware interrupt, watches the die cushion every 20 ms, closes shift totals with time-of-day interrupts, times the lubrication with every IEC timer, and logs faults in error OBs. You deliver the program, an I/O list, a narrative with an OB table, a test record and a hand-over note. The sample pack shows what an integrator delivers for the same press.
- 8documents in the pack
- 9steps to follow
- 6things to hand in
- 16 hof work, at your pace
- Control narrativeControl Narrative: Press PR-3 Production Control
- SDSSoftware Design Specification: Press PR-3 Production Control
- I/O listI/O List: Panel CP-31
- BOMBill of Materials: Panel CP-31 and Field Instruments
- Alarm listAlarm List: Press PR-3
- Interlock listInterlock and Permissive List: Press PR-3
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.
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$28.99 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.
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 internshipPart 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: Hegamurl. Independent creators; the lessons stream from their own channels. EDWartens wrote the study plan, notes, practice tasks and assessments.
Hegamurl · Hegamurl. 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.
- 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 this only for the S7-1500?
Most OBs and all the IEC timers work the same on both. The legacy S7 timers run only on the S7-1500, and a few error OB reactions differ; the notes say where. Everything is shown in PLCSIM.
Why do I need error OBs?
Without OB80 or OB121 a cycle-time overrun or a programming error can put the CPU into STOP, and the line stops with it. Without OB82 a module fault such as a wire break goes unreported. With them the fault is logged, an alarm can be raised, and the CPU keeps running.
Is the Siemens TIA Portal 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 Siemens qualification?
An EDWartens Certificate of Completion, issued when you pass the final assessment, with a verification code anyone can check. It is not a Siemens credential and is never described as one.
Who made the video lessons in the Siemens TIA Portal 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.
How long does the Siemens TIA Portal course take?
Plan on about 6 hours in all, including the video lessons, notes and practice tasks. It is self-paced, so you work through the eight modules at your own speed.
Do I need a real PLC?
No. Everything runs in TIA Portal with S7-PLCSIM, which you can use on Siemens' 21-day trial.
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 Siemens TIA Portal course cover, module by module?
The Siemens TIA Portal course has 8 modules. It opens with "OB1, the Cycle and Cycle Time; OB100 at Startup", goes through "Time-Delay Interrupts (OB20) and Cyclic Interrupts (OB30)", "Error OBs: OB80 Time Error, OB82 Diagnostic Error and OB121 Programming Error", "System Time, Local Time and Time-of-Day Interrupts (OB10)" and "Legacy S7 Timers, Clock Memory and Counting Seconds" and ends with "Final Assessment". The full list with minutes is under "What you learn" on this page.
What can I do after the Siemens TIA Portal course?
After the Siemens TIA Portal course: Read and change the cycle time and use OB1 correctly; Do startup work in OB100 such as counting restarts; Write OB20 time-delay and OB30 cyclic interrupts. 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 Siemens TIA Portal course, and does it cost anything?
For the Siemens TIA Portal course, software: The current TIA Portal trial (21 days) with S7-PLCSIM, on 64-bit Windows 11 Pro or Enterprise; any version from V15 on covers what this course teaches. Hardware: none, everything runs in simulation. The course itself is free.
Is the Siemens TIA Portal course suitable for me, and what level is it?
Siemens TIA Portal is rated intermediate. Intermediate. You should already write ladder in TIA Portal. It is written for engineering students, apprentices, technicians and working engineers in automation, electrical and instrumentation, and takes about 6.5 hours at your own pace.
Which jobs use the skills from the Siemens TIA Portal course?
Skills from the Siemens TIA Portal course (for example: read and change the cycle time and use OB1 correctly) 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
Siemens TIA Portal: Organisation Blocks, Interrupts and Timers, at your own pace. Add the certificate only if you want one.