Siemens PLC Training: A TIA Portal Guide From S7-1200 to S7-1500

Siemens PLC training means learning to program SIMATIC controllers, mostly the S7-1200 and S7-1500, in TIA Portal, Siemens' engineering software. The core skills are hardware configuration, ladder and SCL, program structure with blocks, PROFINET and testing in S7-PLCSIM. You can learn the whole route free in the TIA Portal trial, with no PLC needed.

In this lesson by Instrumentation Tools, you get an introduction to Siemens TIA Portal and the software packages that make it up. It comes from the free TIA Portal in Three Hours course. Watch it first, then read on for how those packages fit together in a real project.

What TIA Portal is

TIA Portal (Totally Integrated Automation Portal) is one engineering environment for several Siemens products. In a single project you configure the PLC hardware, write the PLC program, build the HMI screens and set up drives and networks. The parts you will use most are:

• STEP 7 for the PLC. On its STEP 7 product page, Siemens describes STEP 7 Professional as able to configure, program, test and diagnose all generations of SIMATIC controllers, with STEP 7 Basic as a lower-priced subset. In practice, Basic covers the S7-1200 and Professional adds the S7-1500, S7-300 and S7-400.
• WinCC for operator panels and PC visualisation.
• S7-PLCSIM, which runs your program on a simulated CPU.
• Startdrive for SINAMICS drives, and STEP 7 Safety for fail-safe CPUs.

You do not need to buy any of it to learn. Our guide to the TIA Portal free trial and licences explains what the trial includes and when to install it, and TIA Portal V21: what's new covers the latest release.

Which Siemens controller to learn on

Start with the S7-1200. It is small, it is everywhere on machines, and everything you learn carries over to the S7-1500. Siemens' S7-1200 product page now leads with the second-generation S7-1200 G2, but the programming ideas in this guide apply to both generations. The S7-1500 is the larger family for bigger machines and process lines, with more memory, faster processing, more languages, built-in trace and motion features. You will also meet the older S7-300 and S7-400 in existing plants, often still programmed in STEP 7 V5.x (SIMATIC Manager), and the LOGO! logic module on small jobs.

How a TIA Portal program is organised

Siemens programs are made of blocks, and understanding them is most of the difference between a beginner and someone who can read a real project.

• Organisation blocks (OBs) are called by the operating system. OB1, "Main", runs every cycle. OB100 runs once at startup. Cyclic interrupt OBs (OB30 onwards) run at a fixed interval, which suits PID control. Other OBs handle hardware interrupts and errors.
• Functions (FCs) are blocks without memory. Given the same inputs they produce the same outputs, which suits calculations.
• Function blocks (FBs) have memory, held in an instance data block for each use. A motor FB called for ten motors keeps ten separate sets of timers and states.
• Global data blocks (DBs) hold data that several blocks share, such as recipes or setpoints.
• PLC data types (UDTs) define a structure once, for example everything about one valve, and reuse it in DBs, FBs and HMI faceplates.

On S7-1200 and S7-1500, blocks use optimised block access by default, which lets the CPU arrange data efficiently and means you address data by symbolic name rather than by byte offset. Some older communication methods still need standard access, and you will learn when.

A clean project reads like a table of contents: OB1 calls one block per machine station, each station is an FB, and each FB uses the same motor and valve blocks. The free Build a Machine course is built around exactly this structure.

Languages in TIA Portal

• LAD (ladder) for bit logic and interlocks. Most machine code is written in it.
• FBD for the same logic drawn as boxes, which some engineers find easier for analog.
• SCL (Structured Control Language), Siemens' structured text, for maths, loops, arrays and string handling.
• STL (statement list) on S7-1500 and S7-300/400, mainly for maintaining older code.
• GRAPH on S7-1500 and S7-300/400 for step sequences, with built-in supervision and interlocks.

Learn LAD first, then SCL. They cover most of what you will write.

PROFINET basics you will need

PROFINET is the Ethernet network, maintained by PROFIBUS & PROFINET International, that links a Siemens PLC to its remote I/O, drives, HMIs and other devices. Three ideas cover most beginner problems:

1. Every device has a device name as well as an IP address. The PLC finds its devices by name, so a new or replaced device must be given the right one.
2. Third-party devices are added to the hardware catalogue with a GSDML file from the manufacturer.
3. The topology view records which port connects to which, and lets the PLC detect a device plugged into the wrong place.

The free Industrial Communication course covers PROFINET, Modbus and OPC UA in more depth. For how PROFINET compares with Rockwell's network, read PROFINET vs EtherNet/IP.

Testing without hardware

S7-PLCSIM runs your program on a simulated S7-1200 or S7-1500. With it you can download, go online, watch ladder rungs change colour, use watch tables to change values, and check cross-references to find every place a tag is used. PLCSIM Advanced adds a virtual S7-1500 that other software, such as 3D machine simulators, can connect to over the network. Our first S7-1200 program in TIA Portal and PLCSIM walks through a first project from the new-project screen to a running rung.

A learning order that works

Most learners who follow this order can read and modify a typical S7-1200 machine program in six to eight weeks of regular evenings. For a week-by-week version, see how long it takes to learn PLC programming.

Free Siemens PLC training: which course to take

EDWartens has many Siemens courses, so it helps to know where to start:

• Complete beginner: Siemens TIA Portal, from what a PLC is to a simulated S7-1200 program with an HMI. For the HMI half, your first WinCC HMI screen in TIA Portal is a step-by-step companion.
• Reference-style instruction tour: S7-1200 with TIA Portal: The Tutorial Series goes through every everyday instruction group.
• A full project: TIA Portal: Build a Machine takes a bottling line from functional description to hand-over.
• Next level: S7-1500 Advanced Programming covers optimised access, libraries, GRAPH, SCL and trace.

The Siemens engineer path puts thirteen of the Siemens courses in order, including HMI, PID, safety, WinCC SCADA and the S7-300, and the Siemens courses page lists them with their levels. If you want to know how a completion certificate compares with Siemens' own certification, read are free PLC certificates worth it.

What it costs

Learning is free in full: video lessons by independent YouTube creators (credited on every course page), written notes with worked examples, a practice task per module and one final assessment of 15 questions, 60% to pass, three attempts, then a 24-hour wait and a fresh paper. You need a free account so your progress is saved.

The optional EDWartens Certificate of Completion is a small one-off fee, US$8.99 for a beginner course such as Siemens TIA Portal and a little more for an intermediate course such as S7-1500 Advanced. It can be checked by code at edwartens.com/verification. It is not a Siemens certification, and it is not accredited.

Take the free course

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Siemens TIA Portal

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Siemens S7-1200 with TIA Portal: The Tutorial Series

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Siemens S7-1500 Advanced Programming in TIA Portal

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TIA Portal: Build a Machine