Selecting STEP 7 and PLCSIM Versions for S7-300 PLC Programming

Overview: The STEP 7 and S7-300 Software Stack

The SIMATIC S7-300 was introduced in the mid-1990s as a mid-range modular PLC and remains one of the most widely deployed controllers in factory and process automation. While Siemens has shifted new development to the TIA Portal environment with the S7-1500 generation, the entire S7-300/400 installed base continues to be engineered and maintained with the classic STEP 7 V5.x toolchain and its companion offline simulator, S7-PLCSIM.

Selecting the correct combination of STEP 7, S7-PLCSIM, license model, and download path is a recurring engineering question for new integrators, students, and maintenance teams taking over legacy machines. The decision matrix is dominated by the following constraints:

• Target operating system (Windows 7 SP1, Windows 10 64-bit, Windows Server 2016/2019/2022)
• CPU firmware version and supported instruction set
• Existing project format (classic .S7P archive vs TIA Portal .ap16/.ap20)
• Required engineering extensions (S7-GRAPH, S7-SCL, S7-CFC, S7-PDIAG, S7-FLib)
• Whether offline simulation with PLCSIM is required
• Available license budget and licensing model (single, floating, trial)

This reference documents the supported combinations, installation sequence, license activation flow, and download procedures for both real CPUs and PLCSIM instances.

Prerequisites: Hardware and Operating System Requirements

Supported Operating Systems per STEP 7 Version

The latest legacy version, STEP 7 V5.6 SP1, is the only release that fully supports Windows 10 64-bit and Windows Server 2019/2022 out of the box. Earlier versions can be coaxed onto Windows 10 by enabling the .NET 3.5 compatibility layer and disabling driver signature enforcement, but that configuration is not recommended for production engineering workstations.

Minimum PC Hardware

• CPU: Intel Core i5 or equivalent, 2.4 GHz minimum
• RAM: 8 GB minimum, 16 GB recommended for projects larger than 50 program organization blocks
• Disk: 10 GB free for STEP 7, plus 4 GB for PLCSIM, plus project storage
• Display: 1920 x 1080 minimum for comfortable SIMATIC Manager workspace
• USB: One free port for the license key dongle or for the PC Adapter USB A2
• Optical drive or virtual mount for ISO images

S7-300 CPU Compatibility Matrix

STEP 7 V5.6 SP1 supports every S7-300 CPU family that uses the standard S7-300 backplane, from the oldest CPU 312 IFM up through the latest CPU 319-3 PN/DP. The complete compatibility list is read directly from the CPU MLFB (order number); firmware version is irrelevant for project creation but matters when downloading because newer firmware features are not visible in older STEP 7 versions.

STEP 7 Version Selection

The STEP 7 V5.x line ended at V5.6 SP1; no V5.7 is planned. After V5.6 SP1, new S7-300/400 development moves to TIA Portal V16 or later, which uses a different project format. For maintenance of legacy installations, V5.6 SP1 is the recommended target.

STEP 7 V5.5 SP4

Last stable release for Windows XP and Windows 7 32-bit. Use only when a project must be maintained on a pre-Windows-10 workstation or when legacy S7-300 CPUs (CPU 312 IFM, CPU 314 IFM) need to be programmed with their original firmware options. Does not support 64-bit SIMATIC Manager installation.

STEP 7 V5.6

First release certified for Windows 10 64-bit. Adds support for the CPU 31xT technology CPUs and improves OPC XML-DA export. Required for any new S7-300 project started on a Windows 10 engineering station.

STEP 7 V5.6 SP1

Latest legacy release. Contains bug fixes for hardware catalog updates, IPv4 routing through the integrated IE interface of CPU 31x-2 PN, and PLCSIM co-simulation timing. Siemens strongly recommends V5.6 SP1 for any new project and as the upgrade target from V5.5 SP4 or earlier.

Feature Comparison

S7-PLCSIM Version Selection

S7-PLCSIM is the offline simulator that emulates an S7-300 or S7-400 CPU on the engineering PC. It is licensed separately from STEP 7 and uses its own installation media and its own Automation License Manager key.

PLCSIM Versions and Compatibility

PLCSIM V5.4 SP9 is the matching simulator for STEP 7 V5.6 SP1. It runs as a Windows service called S7-PLCSIM Service and exposes a virtual MPI/TCP adapter that appears to STEP 7 as an MPI node at address 2 (default) or 0 (alternate). The simulated CPU is fully programmable, supports all STL/LAD/FBD blocks, and can be triggered by external signal simulation through the PLCSIM operator panel.

PLCSIM Limitations vs Real Hardware

• Process I/O: must be simulated manually via the PLCSIM I/O panel; no real field wiring
• Timing: OB1 cycle is exact but peripheral access to real I/O is emulated with zero latency
• Communication: PN/DP interfaces are simulated as virtual nodes; no physical port is exercised
• Diagnostic buffer: populated with simulated events only
• Web server: not available on the simulated CPU
• Memory reset / MRES: supported, but format card operations are no-ops
• Failsafe (F-CPU) blocks: not fully validated; use real F-CPU for safety acceptance

Licensing Options

STEP 7 and S7-PLCSIM use the Siemens Automation License Manager (ALM). The license model determines how many concurrent users can run the software and how the key is bound to a PC or a license server.

License Types

Trial License Activation

Siemens offers a 14-day trial of STEP 7 V5.6 SP1 that activates all programming languages and PLCSIM integration. The trial license is delivered as a software key; no physical USB dongle is required. Procedure:

1. Download STEP 7 V5.6 SP1 from the Siemens Industry Online Support portal (article ID 109751706)
2. Install the product; during installation, select Install without license key (trial mode)
3. Launch Automation License Manager from the Siemens program group
4. Select Edit → Install Trial License
5. Sign in with a Siemens account and accept the trial EULA
6. Restart SIMATIC Manager; the 14-day countdown is recorded in C:\ProgramData\Siemens\Automation\ALM\license.log

Step-by-Step: Install, Configure, and Download

Step 1 - Acquire the Software

1. Open support.industry.siemens.com
2. Search for article 109751706 ("STEP 7 V5.6 SP1")
3. Download the SIMATIC STEP 7 V5.6 SP1 DVD image (ISO, ~7.5 GB)
4. Mount the ISO or burn to dual-layer DVD
5. Download the matching S7-PLCSIM V5.4 SP9 image from article 109739098
6. Verify SHA-256 checksum against the value published on the Siemens article page before installing

Step 2 - Install STEP 7 V5.6 SP1

1. Run Setup.exe from the mounted ISO with administrator rights
2. Accept the license agreement and select User-defined installation
3. Enable the components you require:
   • SIMATIC Manager (mandatory)
   • S7-GRAPH (sequential control)
   • S7-SCL (Structured Control Language)
   • S7-CFC (Continuous Function Chart) - optional
   • S7-PDIAG (process diagnostics) - optional
4. Set the installation directory to C:\Siemens\Step7 (default)
5. Complete the installation and reboot when prompted

Step 3 - Install S7-PLCSIM V5.4 SP9

1. Mount the PLCSIM ISO and run Setup.exe as administrator
2. Select Install S7-PLCSIM V5.4 including SP9
3. Accept the path C:\Siemens\PLCSIM
4. Reboot when prompted; verify that the S7-PLCSIM Service is set to Automatic in services.msc

Step 4 - Activate Licenses

1. Start Automation License Manager from the Siemens program group
2. Connect the USB license dongle if a single license is used
3. For floating licenses, connect to the license server via Edit → Connect to License Server (default port 4410 TCP)
4. Verify that STEP 7, PLCSIM, and any optional packages (GRAPH, SCL) show a valid license state
5. If a yellow exclamation mark is shown, right-click the license and select Reactivate

Step 5 - Create the First Project

1. Open SIMATIC Manager
2. Select File → New → Project
3. Name the project (for example, S7_300_First_Project)
4. Right-click the project and select Insert New Object → SIMATIC 300 Station
5. Open Hardware and drag the required modules from the catalog:
   • PS 307 5A power supply (6ES7307-1EA01-0AA0)
   • CPU 315-2 PN/DP (6ES7315-2EH14-0AB0) - or any CPU matching your target
   • DI 32x24 V digital input (6ES7321-1BL00-0AA0)
   • DO 32x24 V digital output (6ES7322-1BL00-0AA0)
6. Assign rack and slot numbers, then Save and Compile the hardware configuration (Ctrl+S)

Step 6 - Download to PLCSIM

1. Start S7-PLCSIM; select CPU 315-2 PN/DP (or matching CPU) from the drop-down
2. Click Power On to start the simulated CPU
3. In SIMATIC Manager, select the SIMATIC 300 Station in the project navigator
4. Right-click and select Download → Hardware Configuration, or use the menu Target System → Download → to Target System
5. If prompted, set the PG/PC interface to PLCSIM (MPI/TCP) via Options → Set PG/PC Interface
6. Confirm the download; SIMATIC Manager reports Download successful in the status bar
7. Repeat for the S7 program blocks (OB1, FB1, DB1, etc.) via Target System → Download

The download procedure to PLCSIM and to a real CPU is identical from STEP 7's perspective; only the PG/PC interface selection changes. For a real CPU, use one of the interfaces below:

The hardware configuration download sequence is described in the official Siemens documentation for S7-300/S7-400 download procedures and applies identically to classic STEP 7 V5.x projects.

Verification: Confirming Successful Download

1. Open Accessible Nodes via Target System → Accessible Nodes
2. The simulated or real CPU should appear in the list with its MPI or TCP address
3. Open Online → Monitor/Modify on the OB1 block
4. Verify that the I/O addresses match the hardware configuration
5. Open the CPU diagnostic buffer via PLC → Diagnostic/Setting → Diagnostic Buffer; verify a Restart (cold start) event is logged
6. In PLCSIM, toggle inputs via the I/O panel and confirm OB1 execution in the monitor window
7. For real CPUs, verify the RUN LED is solid green and the STOP LED is off

Online Status Indicators

Troubleshooting Matrix

Migration Path: Classic STEP 7 to TIA Portal

If the engineering team decides to migrate an S7-300 project to TIA Portal V16 or later:

1. Open the classic project in STEP 7 V5.6 SP1 and archive it via File → Archive → User-defined Archive (.ARC)
2. In TIA Portal, select Project → Migrate project and point to the .ARC file
3. TIA Portal converts S7-300 stations automatically; CPU 31x-2 PN/DP stations retain their Ethernet configuration
4. Re-link any PC station (WinCC flexible, OPC server) since the migration does not preserve PC station configurations
5. Compile the converted project and download to either a real CPU or PLCSIM V16+
6. Run the migration report and resolve any warnings about unsupported blocks

FAQ