Resolving SIMIT PLCSIM Coupling Error with TIA Portal V15

Resolving SIMIT PLCSIM Coupling Error with TIA Portal V15

Problem Description

Engineers integrating Siemens SIMIT with TIA Portal V15 for virtual commissioning frequently encounter the following error when attempting to connect to S7-PLCSIM or PLCSIM Advanced from the SIMIT PLCSIM Coupling component:

Simulation cannot be open. The PLCSIM program is not running. Please start PLCSIM first and then start the simulation.

The error is reported by the SIMIT runtime when the PLCSIM Coupling (or PLCSIM Advanced Coupling) component cannot establish a session with a running PLCSIM instance, even when:

1. A PLCSIM Coupling has been added to the SIMIT chart.
2. S7-PLCSIM V15 (or PLCSIM Advanced) has been launched first.
3. SIMIT is started after the PLCSIM window is visible.

This issue is most common in projects that target an S7-1500 CPU, simulate a robot cell using ABB RobotStudio, and rely on SIMIT for the process/PLC-in-the-loop emulation. The root cause is almost always a product selection or coupling-type mismatch, not a defective installation.

Product Architecture

Understanding the three components in the stack is required to diagnose the failure correctly.

SIMIT acts as the orchestrator. It reads/writes tags from PLCSIM using a coupling component and exposes the same tags to RobotStudio, OPC UA clients, or a PROFINET device.

Compatibility Matrix

Reference: SIMIT V10.0 and STEP 7 (TIA Portal) Getting Started on Siemens SiePortal.

Root Cause Analysis

The error "The PLCSIM program is not running" is reported when the SIMIT coupling cannot locate a registered PLCSIM runtime. The five most common underlying causes, ordered by frequency in field reports, are:

1. PLCSIM version mismatch. The TIA project contains an S7-1500 but the user has only S7-PLCSIM (classic) installed. The classic instance cannot be detected by SIMIT, so the coupling reports the program is not running.
2. Wrong SIMIT coupling type. The user added a classic "PLCSIM Coupling" instead of a "PLCSIM Advanced Coupling" in the SIMIT chart. Classic PLCSIM uses a Windows process handle; PLCSIM Advanced uses the PLCSIM Advanced API on TCP port 102 (S7) plus the PLCSIM Advanced service bus.
3. PLCSIM Advanced service not running. The "PLCSIM Advanced" Windows service (display name: PLCSIM Advanced Virtual Ethernet Service) is required for PLCSIM Advanced to publish its instances. If disabled, the instance starts locally but is invisible to SIMIT.
4. Instance name not matching. The instance name entered in PLCSIM Advanced (e.g., "S71500_1") must match exactly the instance name declared in the SIMIT coupling configuration. Mismatches are case-sensitive.
5. Download order reversed. TIA Portal must download the project to the running PLCSIM Advanced instance before SIMIT can connect. Starting SIMIT against a PLCSIM Advanced instance that has no project loaded still reports the program as not running.

Diagnostic Procedure

Run the following checks before changing configuration. Each takes less than 30 seconds and isolates the failure domain.

1. Identify the CPU family. In TIA Portal, open Project tree → Devices → [CPU] and read the catalog name. If the catalog begins with "6ES7 5xx-\*" (S7-1500 family), PLCSIM Advanced is mandatory.
2. Confirm installed simulation product. Open Control Panel → Programs → Programs and Features. Look for either "S7-PLCSIM V15" (classic) or "PLCSIM Advanced" (advanced). Both may be installed simultaneously without conflict.
3. Check the PLCSIM Advanced service. Run services.msc and locate the service. It must show status "Running" and startup type "Automatic".
4. Validate the virtual Ethernet adapter. In Device Manager → Network adapters, look for "Siemens PLCSIM Advanced Virtual Ethernet Adapter". If it is missing, the PLCSIM Advanced installation is incomplete.
5. Test PLCSIM Advanced in isolation. Start PLCSIM Advanced, create an instance named "TEST", start the instance, then download a minimal TIA project to it. If this works, the SIMIT issue is a coupling misconfiguration rather than a PLCSIM Advanced defect.

Resolution: Step-by-Step

Prerequisites

• Windows 10 64-bit (1809+) or Windows 11 64-bit.
• Administrator rights on the engineering workstation.
• TIA Portal V15 (or later) with STEP 7 Professional installed.
• PLCSIM Advanced V2.0 or later installed and licensed.
• SIMIT V10.0 or later installed and licensed.
• ABB RobotStudio (any recent version).

Step 1 — Install or Verify PLCSIM Advanced

1. Download PLCSIM Advanced from the Siemens SiePortal (search for "PLCSIM Advanced V2.0").
2. Run the installer as administrator.
3. Select the option to install the virtual Ethernet adapter; allow the driver installation prompt.
4. Reboot the workstation when prompted.
5. Activate the license via the Automation License Manager.

Step 2 — Configure the PLCSIM Advanced Service

1. Open Windows Start → Administrative Tools → Computer Management → Services and Applications → Services.
2. Locate PLCSIM Advanced.
3. Right-click → Properties → set Startup type to Automatic.
4. Click Start if the service is not running.
5. Click OK and leave the service running.

Step 3 — Start the PLCSIM Advanced Instance

1. Launch PLCSIM Advanced from the Windows Start menu.
2. In the Instance field, type a unique name (e.g., S71500_SIMIT). Do not include spaces or special characters.
3. Set the Path of project files to a writable folder (e.g., C:\SIMIT\PLCSIM_Advanced\S71500_SIMIT).
4. Leave Local checked for single-workstation use.
5. Click Start. The status column should change to Running.

Step 4 — Download the TIA Project to the Instance

1. In TIA Portal V15, open your project.
2. Select the S7-1500 CPU in the project tree.
3. Go to Online → Extended download to device.
4. In the Target device dropdown, select PLCSIM Advanced.
5. In the Instance field, enter the exact instance name from Step 3 (S71500_SIMIT).
6. Click Search. TIA should find the instance.
7. Select the instance and click Load.
8. Confirm the dialogs. The CPU in PLCSIM Advanced should switch to RUN or STOP (depending on the project configuration).

Step 5 — Add the Correct SIMIT Coupling

1. Open the SIMIT project.
2. Open the chart editor.
3. Delete any existing PLCSIM Coupling components.
4. Drag a PLCSIM Advanced Coupling from the component catalog into the chart.
5. Double-click the coupling to open its configuration.
6. Enter the same instance name (S71500_SIMIT) used in Step 3.
7. Configure the IP address: 127.0.0.1 for local-only coupling, or the virtual Ethernet adapter's IP if coupling with a remote PLCSIM Advanced.
8. Set the rack/slot to match the CPU configuration in TIA Portal (default rack 0, slot 1 for S7-1500).
9. Map the required tags (DBs, M, I, Q) between SIMIT and PLCSIM.
10. Save the SIMIT project.

Step 6 — Verify the Connection

1. Confirm PLCSIM Advanced shows the instance as Running and the TIA project loaded.
2. In SIMIT, click Start simulation.
3. Open the coupling's status dialog. It should display Connected.
4. Force a tag value in PLCSIM Advanced and observe the corresponding SIMIT tag change.
5. If Connected is displayed, the error is resolved.

Configuring SIMIT for ABB RobotStudio

After the PLCSIM Advanced coupling is verified, connect SIMIT to RobotStudio using one of the following methods.

For the typical RobotStudio / SIMIT handshake (handshake bits, gripper commands, conveyor encoder):

1. Define tags in SIMIT that mirror the PLC DBs involved in the cell handshake (e.g., DB100.DBX0.0 = "Cell_Ready", DB100.DBX0.1 = "Cycle_Start").
2. Expose these tags via the SIMIT OPC UA server (endpoint: opc.tcp://<SIMIT_PC>:48000 by default).
3. In RobotStudio, add an OPC UA Client add-in (or a custom RAPID module using the PC SDK) and subscribe to the same tags.
4. Map RobotStudio I/O signals to the OPC UA tags using the I/O Configuration panel.
5. Start the RobotStudio virtual controller in Virtual mode.

Advanced Configuration

Remote PLCSIM Advanced

To run PLCSIM Advanced on a different PC and couple SIMIT to it:

1. On the PLCSIM Advanced PC, allow inbound TCP port 102 and the PLCSIM Advanced service port (default 49152-65535) in Windows Firewall.
2. Start the instance with the virtual Ethernet adapter assigned to the workstation's subnet.
3. On the SIMIT PC, configure the PLCSIM Advanced Coupling with the remote instance's IP address.
4. Ensure both PCs are on the same subnet or have a route between them.

Multiple Instances

PLCSIM Advanced V2.0+ supports multiple instances on the same workstation. Each instance must:

• Have a unique name.
• Use a unique virtual Ethernet IP.
• Be assigned to a unique SIMIT coupling.

The total number of concurrent instances is limited by the PLCSIM Advanced license (counted as "PLCSIM Advanced Instances" in the Automation License Manager).

Performance Tuning

Error Code Reference

Service and Network Verification

Use the following commands in an elevated Command Prompt to verify the runtime environment:

REM Check PLCSIM Advanced service
sc query "PLCSIM Advanced"

REM Verify virtual Ethernet adapter
ipconfig | findstr "Siemens"

REM Test PLCSIM Advanced TCP port (local)
powershell Test-NetConnection -ComputerName 127.0.0.1 -Port 102

REM Check PLCSIM Advanced API process
tasklist | findstr "PLCSIMAdvanced"

REM Verify Automation License Manager
almserver -status

All four checks should return positive results. If the port test fails, the firewall is the most likely cause.

Field-Proven Caveats

Verification Checklist

1. PLCSIM Advanced service is Running.
2. PLCSIM Advanced instance is Running with the correct name.
3. TIA project downloaded successfully to the instance.
4. SIMIT coupling is the PLCSIM Advanced Coupling (not classic).
5. Instance name in the coupling matches the PLCSIM Advanced instance exactly.
6. SIMIT simulation status shows Connected.
7. Tag values update in both directions (PLCSIM ↔ SIMIT).
8. RobotStudio OPC UA subscription receives expected updates.
9. RobotStudio cycle start/stop commands are visible in the TIA program.
10. No error messages in the SIMIT log viewer.

References to Official Documentation

For deeper details, consult:

• SIMIT V10.0 and STEP 7 (TIA Portal) Getting Started — SiePortal
• PLCSIM Advanced Function Manual — SiePortal
• PLCSIM Advanced Installation Guide — SiePortal
• SIMIT V10.0 Manual Collection — SiePortal

Frequently Asked Questions