Resolving SIMOSIM Ethernet Driver Missing in SCOUT V5.1 on VMware

Problem Summary

The SIMOSIM VirtualEthernetAdapter TCPIP entry does not appear under PG/PC Interface after installing SIMOTION SCOUT V5.1 (with the SIMOSIM option enabled) on a Windows 7 SP1 virtual machine running under VMware. The SIMOSIM simulation cannot bind to the Siemens application access point S7ONLINE (STEP7), so the user cannot start a SIMOTION D virtual controller inside the engineering station. The same workstation, when upgraded to SCOUT V5.2, simulates correctly, which isolates the defect to the V5.1 install process on the virtualized Windows guest.

This article is the field-proven procedure to recover the driver, validate the X127 service-channel binding, and either remediate the V5.1 install or migrate to a supported configuration.

SIMOSIM Architecture and the X127 Service Channel

SIMOSIM is a software simulator for the SIMOTION D4x5 platform. Unlike SIMIT, which emulates an entire plant, SIMOSIM virtualizes the SIMOTION D runtime (kernel, technology objects, I/O image) inside the SCOUT process on the PG. Because it must exchange the same engineering protocol that a physical D4x5 uses, SIMOSIM exposes a virtual Ethernet adapter that is reachable through the same TCP/IP stack that SCOUT uses for the real Port X127 service channel.

Because SIMOSIM is bound exclusively to Port X127 of the D4x5, the virtual adapter must be the only entry that shows up under the S7ONLINE access point. If the driver is missing, SCOUT has no way to download the SIMOTION project to the virtual controller, and Connect to target system will fail with a TCP timeout.

System Requirements Verified for SCOUT and SIMOSIM

Before you troubleshoot the driver, confirm the host and guest support the SCOUT version in use. VMware virtualization is supported for SCOUT, but with explicit platform constraints.

The relevant official documents are:

• SIMOTION SCOUT TIA V5.6 – System Requirements (TIA Siemens Cloud readme, section Installation Instructions / System Requirements)
• SIMOTION SCOUT V5.1 HF1 Readme (PDF, Siemens Support entry 109749349) – includes the DCC SIMOTION V3.1 co-install note and the supported virtualization / virus-scanner list

Step-by-Step Diagnostic Procedure

Follow the checks in the order given. Stop as soon as the failure is reproduced and you have a log line to act on.

1. Verify the install option. In the SCOUT V5.1 setup, on the Package selection page, expand SIMOTION SCOUT and confirm that SIMOSIM is checked. If the option was disabled, the driver files are not deployed and the VirtualEthernetAdapter will never register. Re-run the setup, change the install type to User-defined, enable SIMOSIM, and complete the install.
2. Locate the install log directory. Open Windows Explorer in the guest, click into the address bar, and type %AUTINSTLOG% then press Enter. The folder opens with two key files:
   • CommDriverSetup_Log.txt – records NDIS / Siemens communication driver registration
   • Install_Simosim_driver_Log.txt – records the SIMOSIM VirtualEthernetAdapter installation
3. Inspect CommDriverSetup_Log.txt for non-zero return codes. A clean install ends with the line ReturnCode: 0. Typical fault lines you will see on a bad VM install are:
   • Error 0x800F0922 – CBS_E_INSTALLERS_FAILED – Windows could not install the NDIS filter driver
   • Error 0x800F0831 – CBS_E_STORE_CORRUPTION – corrupted WinSxS component store on the guest
   • Error 1232 – ERROR_NETNAME_DELETED – the simulated NDIS device cannot bind to the network stack
4. Inspect Install_Simosim_driver_Log.txt for missing or unsigned .inf, .sys, and .cat files. The driver package is named simntc.inf / simntc.sys (Siemens SIMOTION Network TAP Class driver) and is signed with a Siemens code-signing certificate. If the guest has restricted root certificates, the driver install silently fails.
5. Confirm the virtual adapter is registered with the OS. Open Control Panel → Network and Sharing Center → Change adapter settings. The SIMOSIOM VirtualEthernetAdapter should be present. If it is not, the install did not register the device; this matches the symptom reported in the source thread.
6. Check the PG/PC interface. In SCOUT, open Options → Set PG/PC Interface. In the access point drop-down, choose S7ONLINE (STEP7). Under Interface parameterization used, the entry SIMOSIOM VirtualEthernetAdapter.TCPIP must be selectable. If it is not, the driver service Siemens SIMOSIM NDIS Device is not installed.
7. Validate the service channel port. From an elevated command prompt in the guest, run pnputil /enum-drivers | findstr /i "siemens simosim". The output should list Siemens SIMOSIM NDIS Device with Driver is running = True. If absent, reinstall the driver manually (see next section).
8. Validate Windows Update and root certificates. SIMOSIM's NDIS driver is signed. Windows 7 SP1 must have the certificate chain up to date. Run certutil -f -verify TrustedPublisher\simntc.cat in the %ProgramFiles%\Siemens\Automation\SIMOSIM\driver folder. A failed chain returns 0x800B0100 (CERT_E_EXPIRED).

Root Cause Analysis

Three root causes account for the bulk of field incidents with the symptom "SIMOSIOM VirtualEthernetAdapter does not appear in PG/PC Interface" on a VMware guest:

The source thread specifically reports the SIMOSIM package was enabled ("During the instalation I enabled all the checks") and reinstalled. That eliminates R1 and points to R2: the simntc.inf driver install is failing inside the Windows 7 SP1 VM because the OS is missing the SHA-2 code-signing support update that Microsoft distributed in September 2019. Win7 SP1 without KB4474419 cannot validate SHA-256-signed driver catalogs from vendors that renewed their certificates after 2019, which is exactly the case for the SIMOSIM NDIS driver on the V5.1 media.

Step-by-Step Resolution

1. Apply Windows 7 SHA-2 prerequisite. Inside the VM, install KB4474419 (Servicing Stack Update) and KB4490628 (SHA-2 code-signing support) from Microsoft Update Catalog, then reboot. These updates are mandatory on Win7 SP1 for any driver signed with SHA-256 certificates issued after 2015.
2. Reboot and re-verify the certificate chain. Open certmgr.msc → Trusted Publishers and confirm the Siemens Automation & Drives code-signing CA is present. If not, import the root from %AUTINSTLOG%\SiemensRoot.cer (extracted from the SCOUT install media).
3. Reinstall the SIMOSIM driver manually. From an elevated command prompt: pnputil -i -a "%ProgramFiles%\Siemens\Automation\SIMOSIM\driver\simntc.inf" The expected response is Driver package installed successfully. A failure here produces 0x800F0922 on a guest with corrupt servicing stack – repair with DISM /Online /Cleanup-Image /RestoreHealth before retrying.
4. Confirm the virtual adapter in Network Center. After the manual install, open Network and Sharing Center. The SIMOSIOM VirtualEthernetAdapter is now listed. Right-click → Properties → Internet Protocol Version 4 → set a static address in 169.254.0.0/16 to mirror the X127 convention (for example 169.254.11.21 / 255.255.0.0). Disable all other bindings except TCP/IPv4 to keep the S7ONLINE path clean.
5. Bind SCOUT to the correct access point. In SCOUT, Options → Set PG/PC Interface, select access point S7ONLINE (STEP7) and assign SIMOSIOM VirtualEthernetAdapter.TCPIP. Save and close.
6. Reboot the guest once more. SCOUT caches the access-point mapping in HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\Automation\Scout\5.1\AccessPoint. A reboot forces a fresh enumeration of the NDIS bindings.
7. Open a SIMOSIM project. In the project navigator, right-click the D4x5 station → Start SIMOSIM. The status bar transitions from STOP to RUN. A successful download is confirmed by the message Download to SIMOSIM completed (target: SIMOSIOM VirtualEthernetAdapter) in the detail view.

Verification Procedure

Validate end-to-end behaviour with the following checks before handing the workstation back to the developer:

Workaround: Migrate to SCOUT V5.2 or Later

If the V5.1 install cannot be remediated (for example on a managed image that locks the Windows 7 gold state), upgrade the engineering environment to SIMOTION SCOUT V5.2 or to SCOUT TIA V5.6. The source thread confirms that the V5.2 install on the same VMware guest worked first time, which is consistent with the Siemens hotfix list: V5.2 ships a re-signed simntc.cat that no longer relies on the legacy SHA-1 chain. For greenfield installations, prefer SCOUT TIA V5.6 with VMware vSphere ESXi 6.7 (or VMware Workstation 12.5.5 for WinCC clients), as documented in the TIA Siemens Cloud system requirements readme.

VMware Guest Configuration Notes

SIMOSIM is sensitive to the VMware network adapter type and to the network label of the virtual switch it is bound to. The two configurations that consistently work on Win7 SP1 guests are:

Additional VMware-level rules that field engineers should follow:

• Enable Connect at power-on on every virtual NIC; the SIMOSIM TAP driver queries the parent bus on every VM start and will fail to initialize on a disconnected NIC.
• Set the virtual switch port group to a dedicated SCOUT/PG VLAN if the production network is reachable from the VM, to avoid address conflicts on 169.254.x.y.
• Do not enable Promiscuous Mode on the port group; the SIMOSIM NDIS filter will duplicate frames and confuse the S7ONLINE stack.
• Disable Windows Firewall on the SIMOSIOM VirtualEthernetAdapter in the guest. The firewall injects WFP filters that block the S7 broadcast used by SCOUT for device discovery.
• Keep VM snapshot chains short. Reverting to a snapshot taken before SIMOSIM is installed reverts the driver and breaks the binding; the driver install must be reapplied.

Co-Install: DCC SIMOTION V3.1 on SCOUT V5.1 HF1

If you are running SCOUT V5.1 HF1 and need DCC (Drive Control Chart) authoring for SIMOTION, the Siemens readme confirms that DCC SIMOTION V3.1 is the matching co-install. Install order must be SCOUT V5.1 → HF1 → DCC SIMOTION V3.1 → SIMOSIM option. Reordering the DCC install after SIMOSIM is known to break the VirtualEthernetAdapter binding because DCC redeploys shared Siemens automation services.

Frequently Asked Questions