Siemens PLC training — TIA Portal, S7-1200 / S7-1500

Siemens is the controller you are most likely to meet on a serious South African plant. If you are starting Siemens PLC training in 2026 and you want a sober view of what to learn, in what order, and which marketing claims to ignore, this is the page. We program S7-1200 and S7-1500 ourselves, we run TIA Portal V19 daily, and we are not a Siemens sales channel. We are an independent training site that thinks the official courseware is too expensive for self-funded learners and the YouTube alternatives are too shallow.

Why Siemens dominates SA petrochem and water

Walk into a South African petrochem refinery, a municipal water treatment works, a mining beneficiation plant, or a pulp and paper mill, and the panel doors open onto Siemens hardware seven times out of ten. The bias is regional and historical. The big EPC contractors that built the post-1980 industrial belts in Gauteng and KwaZulu-Natal standardised on Siemens because the German engineering houses they partnered with did. Once a site has 40 panels of S7-300 and a WinCC SCADA layer on top, it stays Siemens for the next two replacement cycles. Petrochem leans Siemens. Water utilities lean Siemens. Mining beneficiation, especially the metallurgical end where furnace control matters, leans Siemens. Pulp and paper, the same.

The exception is the Western Cape. The Cape's food and beverage sector grew on Allen-Bradley because the OEMs supplying packaging machines into that market were largely North American or licensed from North American designs. So if you are in Cape Town and you are looking for FMCG work, Rockwell pays the rent. Anywhere from Durban inland through Secunda, Sasolburg, Witbank, Johannesburg and the platinum belt, Siemens dominates. This is not a marketing claim. It is what the panel photos on Pnet job ads show, and it matches what the local instrumentation managers we talk to say about their installed base.

A practical implication for someone choosing a brand to learn first: if you live anywhere east of Bloemfontein, learn Siemens before you learn Rockwell. The job density favours Siemens by a wide margin in those provinces. The general PLC training guide covers the broader brand split and the skills the SA market actually pays for, in case you have not picked a primary platform yet.

The Siemens hardware family you'll actually meet

Siemens sells a lot of CPUs. You only need to know a small subset for the work that exists in South Africa.

S7-1200. The compact mid-tier controller. CPU 1211C, 1212C, 1214C and 1215C. Built-in I/O on the CPU itself, expandable with signal modules and signal boards. You will see this on small water booster pump skids, OEM machine builds, conveyor sections and standalone process units. Programmed in TIA Portal Basic or Professional. Dominant memory size is between 75 KB and 150 KB of work memory.

S7-1500. The high-performance controller. CPU 1511, 1513, 1515, 1516, 1517 and 1518, with the PN/DP variants and the F (failsafe) variants. The 1517-3 PN/DP is the one you'll see on serious greenfield process plants. Backplane-mounted, with a separate power supply and an extensive range of modules. Requires TIA Portal Professional and the Step 7 Professional licence.

Legacy S7-300 and S7-400. Discontinued for new sales but still on the bulk of brownfield panels. CPU 315-2 PN/DP, CPU 317-2 PN/DP, CPU 319 and the redundant H-systems. You will spend a meaningful share of your career maintaining these. They are programmed in classic Step 7 (Simatic Manager) or via the TIA Portal migration path. The S7-400H redundant pairs sit on top of refinery distillation columns and you do not touch them without paperwork.

Modules to memorise. SM 1221 for digital input, SM 1222 for digital output, SM 1223 for mixed digital, SM 1231 for analogue input, SM 1232 for analogue output, SM 1234 for mixed analogue. SM 1278 for IO-Link masters. CM 1241 for serial communications (RS-232, RS-422, RS-485). CP 1543-1 for industrial Ethernet with security, CP 1543SP-1 for the ET 200SP rack, CP 1242-7 for GPRS. ET 200SP and ET 200MP for distributed I/O over Profinet. The ET 200SP HA range for process I/O.

Drives that talk to these PLCs. Sinamics G120, G120C and G120X for general-purpose VFDs. Sinamics S120 for servo and high-end motion. The Sinamics range talks Profinet and Profibus natively and the drives are configured from inside the same TIA Portal project as the PLC, which is one of the genuine advantages of the Siemens ecosystem.

TIA Portal — the IDE you must learn

The Totally Integrated Automation Portal is Siemens' single development environment for PLC, HMI, drive and network configuration. The current shipping versions are V18 and V19. V20 is rumoured for late 2026. License tiers matter: TIA Portal Basic supports S7-1200 only. TIA Portal Professional supports the full range including S7-1500, S7-300, S7-400 and the safety variants. WinCC Comfort, Advanced and Unified are separate licence add-ons for the HMI work.

The project tree is the spine of the IDE. Devices and networks at the top, then per-device folders for program blocks, technology objects, PLC tags, watch tables, traces, and online & diagnostics. Get used to the right-click context menu — almost everything you need lives there. The compile button is the green tick. The download button is the arrow with the brown PLC icon. The go-online toggle is the pair of glasses.

A few honest notes on TIA Portal quirks that no Siemens marketing slide will tell you. First, the project file is a binary directory tree, not a text format. Version control with git works only at the "TIA Portal Openness" XML export level, and the UI for that round-trip is brittle. Most teams ship by emailing zipped project archives. This is genuinely bad practice and Siemens has not fixed it. Second, the multi-user engineering server is real and works, but it adds infrastructure cost (a Windows server, a service licence) that small panel shops cannot justify. Third, once you upgrade a project from V18 to V19, you cannot open it in V18 again. Plan your upgrades. Fourth, the start-up time on a laptop with less than 16 GB of RAM is painful. Fifth, the PLC simulation, PLCSIM, is bundled with Basic and Professional but the advanced version is a separate paid product.

Languages on Siemens — LAD, FBD, SCL, GRAPH

Siemens supports the IEC 61131-3 family of languages: ladder diagram (LAD), function block diagram (FBD), structured control language (SCL, which is Siemens' name for structured text), GRAPH (sequential function chart) and statement list (STL — deprecated for new code). The standard itself is published by the IEC and is the reference document for cross-vendor language semantics: iec.ch/standards/iec-61131-3.

Most South African Siemens programmers write everything in LAD. Six-hundred-rung ladder programs are normal in older sites. They are also a maintenance nightmare. The opinion: this is wrong. The right answer for a serious S7-1500 project in 2026 is FBD for everyday combinational and sequential control logic, SCL for batch sequencing and any non-trivial maths, and GRAPH for unit-procedure step logic where you have a clear step-and-transition structure. Use LAD only for the parts of the logic that field technicians genuinely need to read live — typically the interlock summary and the manual override page.

A small SCL example, the kind of thing you would write inside a function block to scale a 4-20 mA pressure transmitter to engineering units. The raw analogue value from the SM 1234 channel sits in #raw (an Int between 0 and 27648 for the active range), and we want a Real in bar between 0 and 10:

IF #raw < 0 THEN
    #pressure_bar := 0.0;
    #under_range := TRUE;
ELSIF #raw > 27648 THEN
    #pressure_bar := 10.0;
    #over_range := TRUE;
ELSE
    #pressure_bar := INT_TO_REAL(#raw) * (10.0 / 27648.0);
    #under_range := FALSE;
    #over_range := FALSE;
END_IF;

That is six lines that do the same job as a twelve-rung ladder block, with the bonus of being readable in a code review. If you cannot write that, you are not done with Siemens PLC training yet. SCL is non-negotiable for anyone touching an S7-1500 in a serious plant.

Addressing on Siemens — absolute vs symbolic

Siemens addressing is one of the harder transitions for someone coming from Allen-Bradley. The absolute notation is what you see in the manual: %I0.0 is digital input byte 0 bit 0. %Q0.1 is digital output byte 0 bit 1. %MW10 is memory word 10. %IW64 is the input word at byte address 64, typically the first analogue input on a process module. %DB1.DBX0.0 is data block 1, byte 0, bit 0.

Symbolic addressing in TIA Portal lets you give every absolute address a tag name in the PLC tag table, and then you write Pump_1_Run_FB instead of %Q4.2. Always use symbolic. The absolute form is for the cross-reference report, not for daily programming.

The mistake newcomers make is forgetting that data blocks are non-volatile by default and that nothing stops you from overlapping addresses across DBs. You can write 200 bytes into DB10 starting at offset 0, and another piece of code can write 200 bytes into DB10 starting at offset 100, and both will compile and run. Use the "optimised block access" attribute on every new data block — it disables byte-offset addressing and forces all access to go through tag names, which catches this whole class of bug at compile time. The only reason to use a non-optimised DB is when you are talking to a legacy library that requires byte-level structure compatibility.

A second newcomer mistake is using %MW memory words for state that should be in a data block. M-memory has a fixed byte map across the whole CPU and any function can write to any M address. DBs scope the data to a function block instance. Put your state in instance DBs. Reserve M-memory for the system flag byte and a small number of plant-wide latched flags.

PLCSIM and S7-PLCSIM Advanced

Siemens ships two simulators. PLCSIM is bundled with TIA Portal Basic and Professional and runs S7-1200 and S7-1500 simulations on the same PC as the IDE. It supports almost the full S7-1500 instruction set but does not support distributed I/O over Profinet, the failsafe instruction set, or hardware-in-the-loop with external Profinet partners. Good enough for code-level testing. Free with the Portal.

S7-PLCSIM Advanced is a separately licensed product that runs the simulated CPU as a virtual controller with a real Profinet stack, full failsafe support, and the ability to integrate with third-party process simulators over OPC UA or shared memory. It is what serious factory acceptance test rigs use. The price is significant — the order of magnitude is in thousands of euros per seat — and it is not a tool for a self-funded learner. The official documentation entry is the Siemens Industry Online Support landing page for PLCSIM Advanced: support.industry.siemens.com/cs/document/109759512.

What PLCSIM and PLCSIM Advanced give you that we do not try to replicate: full instruction-set fidelity, the actual TIA Portal download experience, the real diagnostic buffer, and the integration with WinCC Unified for HMI testing.

Where our browser simulator fits

We are not PLCSIM. We do not pretend to be. We give you something different and complementary. Our simulator runs in a browser tab, with no installation, on any laptop or Chromebook with a current Chrome or Firefox. The scan engine matches IEC 61131-3 semantics — rung-by-rung evaluation, instance-data persistence on function block calls, deterministic timer behaviour, and the same race conditions you would see on a real CPU when scan order matters.

What you get from us is ladder logic reflexes, IEC 61131-3 semantics, and pattern fluency. By the time you sit in front of TIA Portal for the first time, you already know how a TON behaves when the rung goes false mid-timing, how a sealed-in start-stop reads on the input scan, and how scan order affects an SR latch when the set and reset rungs are written in the wrong sequence. You will still need to learn TIA Portal's own UI and the S7-specific instructions — MOVE, BLKMOV, FILL_BLK, the SCALE_X and NORM_X scaling functions, the PID_Compact technology object and the PID_Temp variant for heat-exchanger control. We do not replace that. We build the underlying programming brain so that the Siemens-specific layer takes weeks instead of months.

The wiring track and sensor school are the bridge content for Siemens learners specifically. The wiring track shows you a labelled SM 1223 signal module and walks you through wiring a 24 V DC sensor (PNP), a dry-contact pushbutton, and a 4-20 mA transmitter through an SM 1231 channel. The sensor school covers the 22 sensor types most common on local petrochem and water plants, with the engineering-unit scaling you would set in a NORM_X / SCALE_X pair.

The Siemens cert path — what's worth doing

Siemens runs an official training programme called SITRAIN. The South African branch lists courses through the European catalogue, with on-site delivery in Midrand and Cape Town. Course list and pricing live at siemens.com/sitrain. A typical SITRAIN course in South Africa runs between R18 000 and R45 000 for a four or five-day classroom session, depending on whether it is the basic ST-7PRO1 (TIA Portal fundamentals) or the more advanced ST-PROSAFE (failsafe programming) or ST-PROAS (advanced process automation).

The honest take. SITRAIN is the gold standard if your employer is paying. The instructors are real Siemens engineers, the lab racks are real S7-1500 hardware, and the certificate carries weight in interviews specifically because it is expensive — hiring managers know your employer thought you were worth the investment. For a self-funded learner, SITRAIN is an expensive way to learn syntax. Forty-five thousand rand for five days of TIA Portal fundamentals is hard to justify when you can get the same syntactic coverage from the official Siemens manuals (free) and a simulator subscription (a few hundred rand a month) over six months of self-paced practice.

For a self-funded learner who wants a cert that carries weight internationally, the ISA CCST (Certified Control Systems Technician) is the better bet. It is vendor-neutral, which is a feature not a bug — South African instrumentation people who get hired in Saudi Arabia or Australia carry the CCST, not a SITRAIN certificate. The CCST also costs around USD 600 for the exam, which is roughly the price of one SITRAIN classroom day.

Deep dives on Siemens

The brand pillar above is the overview. The pages below are the topic-by-topic deep reads — written for someone who has already decided Siemens is their primary platform and now needs the specifics. Each one is a single-topic page with worked examples and the kind of detail that takes a working programmer past the surface.

1. Siemens TIA Portal basics: project tree, devices, and tags — the practical orientation read for anyone opening TIA Portal for the first time.
2. Siemens TIA Portal FB instance DBs vs Allen-Bradley AOIs — for techs crossing over from Rockwell who need the mental-model translation.
3. Siemens S7-1200 vs S7-1500: when each platform is the right pick — the platform-pick page for greenfield projects and panel-shop quotes.
4. Siemens WinCC Unified screens: tag binding and faceplate basics — the HMI side of the Siemens stack, with the screen-tag plumbing newcomers always trip on.
5. Migrating from STEP 7 Classic to TIA Portal: the practical path — for the brownfield S7-300 and S7-400 sites that still need a migration plan.

Where you'd work with Siemens

Siemens job density in South Africa is lopsided. The platform owns the petrochem corridor and the refining belts, which means the cities worth a brand-specific page are the ones that sit on top of that infrastructure. Two are worth reading before you commit a learning plan.

In KwaZulu-Natal, Siemens PLC training in Durban is the page for anyone working the south basin refining and petrochem cluster — the panel doors there open onto S7-300 brownfield and S7-1500 retrofits more often than any other platform, and the local instrumentation managers hire on TIA Portal fluency over generic ladder experience.

Inland, Siemens PLC training in Sasolburg is the page for the petrochem and specialty-chemicals corridor that runs from Sasolburg through Secunda. The installed base there is overwhelmingly S7-400 with a slow migration to S7-1500 over the next replacement cycle, which means a Sasolburg technician spends real time on classic Step 7 alongside TIA Portal — and that combination is where the rates are highest.

What we don't claim

This page is going to be honest about what we are and aren't. We are not a Siemens-authorised training provider. We have no commercial relationship with Siemens. We do not represent SITRAIN, we do not issue SITRAIN certificates, and we do not have access to Siemens proprietary courseware. Our completion certificates are course-level only and have no regulatory standing — not in South Africa and not internationally. We are not SAQA-registered or nationally accredited, and we have not pursued QCTO accreditation or MerSETA registration.

What we are: an independent simulator and curriculum that helps you build the reflexes you need before you spend SITRAIN money or sit a CCST exam. The formal vendor cert is a separate purchase from a separate vendor. We are honest brokers. If you specifically need a SETA-aligned learnership for B-BBEE skills development reasons, we are not the right product.

How to start

Five steps. Sandbox first — open the simulator, drag a contact and a coil, write your name across the screen in rungs. Then the start-stop module — write the classic three-wire control with a sealed-in start, a stop button, and an output to a virtual contactor. Then the seal-in motor with overload — add a thermal overload contact, model the contactor's auxiliary feedback, and learn what a "field check" interlock pattern looks like before you write one on a real Siemens project. Then a TON-driven sequencer — five-step bottle-filling cycle, with the timer behaviour and the step-transition logic that maps directly to GRAPH in TIA Portal. Finally, port the same logic into TIA Portal once you have access to a copy, and watch how little of the work has to be redone.

Free tier first — no credit card. Spend a weekend on the sandbox and the first few lessons. If the format works, move to Basic at $12 a month. Most learners reach the start of the brand-specific Siemens content in three to four weeks of part-time practice.