This engineering brief describes how to build a trainer based on the Siemens S7-1200 Gen 2 safety PLC. The assembly shown in Figure 1 includes 24 VDC power distribution, user controls, and a motor starter along with a DigiKey-designed three-phase motor simulator. The parts list for the unassembled kit is included here.
Key Takeaways
-
The core controller is a Siemens S7-1200 safety PLC, which lets students work with both standard automation and functional safety concepts in the same system.
-
The trainer is best understood as a local control panel with expansion capabilities. This includes an HMI, IO-Link, and ET 200SP distributed I/O.
-
It is best suited to capstone-style training, where students need hands-on experience with wiring, startup, debugging, and programming on field-relevant hardware.
This article is part of the DigiKey Field Guide for Industrial Automation
Location: Teach It → Kits
Difficulty: 
Engineer — difficulty levels explained
Author: Aaron Dahlen | MSEE | Senior Applications Engineer, DigiKey
Last update: 24 Mar 2026
Figure 1: Image of the DigiKey Siemens PLC trainer.
Design Philosophy
The trainer is best viewed as a local control panel with expansion capabilities. Figure 2 suggests the possibilities with an HMI, safety modules, IO-Link, and distributed I/O with the ET 200SP. Students are encouraged to learn wiring and PLC fundamentals on the trainer and then branch out.
Components were chosen to reflect the logistics of a Siemens-focused panel shop. This includes the PLC, motor starter, as well as the selector switches and pushbuttons. You are encouraged to modify the list to best fit your curriculum needs.
Figure 2: PLC trainer on the workbench surrounded by an HMI, IO-Link master, and ET 200SP distributed I/O.
Education Content
DigiKey has published education material on industrial automation. We recommend starting with these introductory topics as they lay the foundation for industrial wiring before the PLC complexity is added.
- First Steps for DIN rail hardware
- Construct the Phase Dock base and DC power distribution block
- Fundamentals of industrial switches
- Relays and ladder diagrams
- Introduction to the Magnetic Motor Starter
In addition to hardware, DigiKey has articles on Siemens specific PLC programming.
Purchasing
The parts list for the unassembled kit is provided as a DigiKey MyList. Think of this as a starting point for building a Siemens PLC trainer. You are encouraged to review the individual components and make substitutions to best match your needs.
Hookup wire and wire ferrules are not included in the kit. We used these common shop supplies during assembly.
- Blue 22 AWG Alpha Wire 3053 BL001
- Blue with white stripe Alpha Wire 3053 WU001
- Ferrule Schneider Electric DZ5CE007
- Ferrule crimp tool Phoenix Contact 1213146
Wire Diagram
The simplified wire diagram for the trainer is shown in Figure 3. The previously mentioned Education Content documents how to construct the phase dock platform and the power distribution.
Power
The trainer requires 24 VDC at approximately 500 mA. An external bench power supply may be used.
Figure 3: Simplified wire diagram for the Siemens PLC trainer.
Siemens PLC Software
The TIA Portal PLC licenses come in basic or professional levels:
- S7 Basic — for S7-1200 family (Basic PLCs)
- S7 Professional — for S7-1500 family (Advanced PLCs) + S7-1200 is also included
- S7 Professional Combo — Everything included in S7 Professional + legacy devices
There are more licenses available for specific, advanced, or industry focus requirements. This includes advanced simulation or safety.
Trial License
When you first download TIA Portal on a computer and try to use a device for which you don’t have a license, the software will give you a 21-day free trial license to use.
Full Version License
There are three ways to acquire a full license:
- Purchasing a permanent floating license — doesn’t expire
- Subscription model — auto-renewal
- Renting a license — for short periods of time
Featured Components
Siemens S7-1200 Safety PLC
The trainer features the Siemens CPU 1212FC DC/DC/DC with the analog module. This offers several advantages:
-
The safety functionality allows students to explore Safety Integrity Level (SIL) and Performance Level (PL) applications using ET 200SP expansion modules.
-
Solid-state outputs allow pulse-width modulation experimentation.
-
The analog module features two inputs and two outputs for student experiments involving 4-20 mA or 01 to 10 VDC field devices.
We could have used CPU 1212C DC/DC/DC to save cost. However, this is not a safety PLC, which places significant limitations on advanced topics.
Banner S22 Touch Button
The Banner S22AMTSGRY3 incorporates a non-contact pushbutton and multicolor panel indicator lamp. It is programmable using the technique described here for the related Banner K50 touch button. With two control lines, four unique display patterns may be selected.
Programming is not required assuming we use the default off, red, yellow, green states as shown in Figure 4.
Figure 4: Default programming of the Banner S22 pushbutton.
Siemens 3RT2016 Motor Starter
The 3RT2016 is configured as a basic three-phase motor starter with accessories:
-
Thermal overload block is included. Students can activate the thermal overload using a DC power supply to gain a better understanding of the time vs current curves.
-
The clip-in surge suppressor, along with the external interposing relay allow students to better understand system-level aspects of PLC interfacing. This article describes the relationship between diode type and speed of contactor release.
-
A normally closed auxiliary contact block is included for state-based control of the contactor.
E-T-A Electronic Circuit Protector
An E-T-A electronic circuit protector is included. This provides fast current limiting to minimize the unfortunate student wiring errors. Note that this solid-state circuit breaker has near-instantaneous current limiting as opposed to a thermal/magnetic trip breaker which allows significant transient current.
Continue Exploring Industrial Control Systems
If this discussion was helpful, you may also want to explore:
DigiKey Navigation
- Full Catalog: Industrial Control & Automation
About This Author
Aaron Dahlen, LCDR USCG (Ret.), is a Senior Applications Engineer at DigiKey in Thief River Falls. His background in electronics and industrial automation was shaped by a 27-year military career as both technician and engineer, followed by over a decade of teaching.
Dahlen holds an MSEE from Minnesota State University, Mankato. He has taught in an ABET-accredited electrical engineering program, served as coordinator of an electronic engineering technology program, and instructed military technicians in component-level repair.
Today, he has returned to his home in northern Minnesota, completing a decades-long journey that began with a search for capacitors. Read his story here.