Key Takeaway
The main software used for programming S7-300 PLCs is SIMATIC Step 7 Classic (V5.x series).
This includes:
Hardware configuration
Ladder Logic (LAD), Function Block Diagram (FBD), Statement List (STL) programming
Networking configuration (MPI, Profibus)
Diagnostics and troubleshooting tools
Later versions of TIA Portal (V13 onward) also support S7-300 programming and configuration, enabling easier project integration with newer hardware like S7-1200 and S7-1500.
However, older plants mainly use Step 7 Classic.
Hardware support and spare parts for S7-300 will continue for many years, despite Siemens announcing product lifecycle end dates for new production.
Overview of STEP 7 Classic for S7-300
If you’re just stepping into the world of Siemens S7-300 PLCs, the very first thing to understand is that this series is mainly programmed using STEP 7 Classic (SIMATIC Manager). This software has been the backbone of Siemens automation for years and is deeply trusted in the industry.
Think of STEP 7 Classic as the veteran engineer in your plant — reliable, robust, and deeply experienced. It was specifically developed for the S7-300 and S7-400 PLCs and became the standard tool for configuring hardware, writing logic, and handling diagnostics.
It gives users full control over programming using LAD (Ladder Logic), FBD (Function Block Diagram), and STL (Statement List). And yes, this is exactly the software you’ll find running on legacy systems across thousands of industries. If your factory still runs on S7-300s, STEP 7 Classic is most likely in your toolkit.
Features and Programming Tools
What makes STEP 7 Classic so popular among seasoned engineers? It’s the sheer number of built-in tools it provides. From hardware configuration to diagnostics, it handles everything in a single environment.
You can:
Configure and address I/O modules
Program logic in multiple languages
Upload/download logic to PLCs
Perform online diagnostics and force signals
It also supports symbolic programming — meaning, you can name your I/O with easy-to-read tags like “Pump_Start” instead of using raw addresses like I0.0. This makes life easier, especially when troubleshooting or handing over your program to someone new.
And let’s not forget about function blocks, libraries, and modular programming — a must-have when you’re working on large projects that need structure and repeatability. If you’re building complex automation sequences, STEP 7 gives you that modular edge.
Support in TIA Portal (Limited Compatibility)
Now comes the twist. Siemens launched TIA Portal (Totally Integrated Automation Portal) to unify programming across all their hardware. It’s modern, user-friendly, and very powerful. But — and this is important — S7-300 is not natively designed for TIA Portal.
Some later S7-300 CPUs can be used in TIA Portal, but support is limited. TIA Portal is mainly designed for S7-1200, S7-1500, and newer devices. So if you try importing an older STEP 7 Classic project into TIA, it might not fully work.
Does that mean S7-300 is outdated? Not really. Many industries still run on these systems due to their stability and long lifecycle. But if you’re planning a future-ready setup, moving to S7-1500 with full TIA support is worth considering.
In short — yes, you can use TIA Portal for some S7-300 CPUs, but STEP 7 Classic remains the recommended tool.
Licensing and Software Requirements
Let’s talk logistics. STEP 7 Classic isn’t free software — it comes with a licensing model. You’ll need a valid license key to unlock full functionality.
There are different versions, but STEP 7 Professional is the most common for S7-300 programming. It includes:
SIMATIC Manager
Programming languages (LAD, FBD, STL)
Hardware configuration
Networking tools (for PROFIBUS/PROFINET)
Make sure your system meets the requirements. STEP 7 Classic typically runs on Windows 7 or older — newer Windows versions might require compatibility tweaks or virtualization.
Also, the license is tied to your PC’s hardware. So, if you’re changing systems, make sure to transfer your license properly using Siemens’ Automation License Manager.
TIP: Always use genuine Siemens software. Cracked versions are not only illegal but can also cause major headaches during project deployment.
Installation and Configuration Process
Installing STEP 7 Classic isn’t too complex, but it’s not plug-and-play either. First, ensure your PC matches the system requirements. Then follow these steps:
Insert the installation media or download from Siemens’ official site (with login).
Install the Automation License Manager.
Install STEP 7 Classic and activate the license.
Launch SIMATIC Manager.
Once you’re inside SIMATIC Manager, you can create a new project, define your CPU model, and start configuring the hardware. It’s critical to match the exact CPU and module types — even one wrong selection can cause communication errors.
The environment is old-school, yes — but once you get used to it, it becomes a powerful workspace. You’ll find project folders, cross-references, and even tools for comparing logic versions.
If you’re working on a networked setup (like PROFIBUS), make sure you understand how to configure network addresses and device IDs. This is often where beginners get stuck.
Conclusion
So, what’s the verdict?
If you’re working with a Siemens S7-300 PLC, your go-to software is STEP 7 Classic. It’s reliable, time-tested, and packed with tools designed specifically for the S7-300 family. While TIA Portal offers a modern interface and better integration, its support for S7-300 is limited.
For professional automation engineers — and even for newcomers — learning STEP 7 Classic is still a valuable skill. It’s like knowing how to drive a manual car: once you master it, you’ll understand the core of industrial automation deeply.
Whether you’re programming, debugging, or expanding an old system, mastering STEP 7 Classic will make you stand out as an engineer who truly knows their tools.