Resolving 'No Network Adapter' Fault in Siemens Primary Setup Tool (PST)

The Primary Setup Tool (PST) is the Siemens commissioning utility used to discover, configure, and program the S7-200 SMART CPU family and associated SMART signal boards/modules over Ethernet. A recurrent commissioning complaint is the fault string "No network adapter" (sometimes surfaced as "No network adapters found") raised by the PST Browse dialog or under Settings > Communications. The tool reports no selectable NIC even though the same Windows host can browse the internet or connect to STEP 7 / TIA Portal with no problems. This reference walks through the validated recovery path: from verifying the operating system stack, to realigning the PG/PC interface assignment, to the registry-level integrity check, to a clean PST reinstall.

1. Problem Definition and Symptom Matrix

The "No network adapter" fault is a client-side discovery failure inside the PST communications layer. The PST hosts a small Winsock-based scanner that enumerates local NICs to send UDP discovery packets to the S7-200 SMART CPU (default UDP port 2366, the ISO-on-TCP / S7-200 SMART discovery port) and to bind the TCP connection used for project upload/download. When the scanner returns an empty list, the dialog disables the Find CPUs button and the Settings combo box under Communications is blank.

2. Root Cause Analysis

Five independent root causes reproduce this fault. They are ordered by frequency seen in field escalations:

1. PG/PC interface access point not bound. PST relies on the Siemens Set PG/PC Interface control panel applet to bind a logical access point (e.g., S7ONLINE) to a physical NIC plus protocol. If the access point is unassigned, PST reports no adapter even though Windows sees the NIC.
2. TCP/IPv4 protocol stack not bound to the NIC. PST uses the standard Winsock 2 provider. If the user has unchecked Internet Protocol Version 4 (TCP/IPv4) in the NIC's properties pane (often done to "force" a static address), the PST scanner returns zero adapters because the protocol that PST binds to is missing.
3. Winsock catalog corruption. Windows update, VPN client install/uninstall, or aggressive network troubleshooting scripts can corrupt the Winsock LSP catalog. Result: the NIC exists in Device Manager and the registry but is invisible to user-mode Winsock consumers like PST.
4. Registry enumeration discrepancy. The HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards sub-tree holds the canonical record of installed NICs. If the registry tree is missing entries (often after a Windows repair upgrade or a NIC driver clean-sweep utility), PST receives an empty list. Microsoft documents this exact failure mode in Network Adapters Not Displayed in Advanced Network Settings.
5. PST installation profile corruption. PST stores its last-known access point under %APPDATA%\Siemens\Primary Setup Tool and the per-adapter diagnostics cache under %PROGRAMDATA%\Siemens\Automation\PST. A broken profile can mask the NIC list on next launch until the profile is reset or PST is reinstalled.

3. Solution Path A — Verify the Operating System Sees the Adapter

Before touching PST, confirm Windows itself is presenting the NIC to user-mode applications.

3.1 Check Device Manager

1. Right-click Start > Device Manager.
2. Expand Network adapters. The expected Intel/Realtek/Broadcom NIC must be present with no yellow bang.
3. If the device has a yellow bang, right-click → Update driver → Search automatically for drivers. Reboot.

3.2 Verify the NIC Has a Valid L2/L3 Stack

1. Open Settings > Network & Internet > Status > View hardware and connection properties (Windows 10/11). The NIC should show a valid IPv4 address, subnet mask, and a default gateway reachable via ping.
2. From an elevated command prompt run ipconfig /all. Capture the description string — PST matches the description field, not the friendly name.

3.3 Confirm TCP/IPv4 Is Bound

1. Open Control Panel > Network and Sharing Center > Change adapter settings.
2. Right-click the NIC → Properties.
3. Verify that Internet Protocol Version 4 (TCP/IPv4) is checked. This is the single most common reason the PST scanner returns empty.
4. Optionally click Configure... > Advanced > Link Speed & Duplex and force 100 Mbps / Full Duplex if the switch port is fixed. The S7-200 SMART CPU's Ethernet port auto-negotiates to 100 Mbps / Full.

4. Solution Path B — Configure the PG/PC Interface Access Point

Once the OS sees the NIC, align the Siemens access point.

1. Launch Start > Siemens Automation > Set PG/PC Interface (or search PGPC).
2. In the Access Point of the Application dropdown, select S7ONLINE (used by PST and STEP 7 Micro/WIN SMART).
3. In the Interface Parameter Assignment Used list, select the physical NIC plus TCP/IP → (your NIC description). The exact description string must match what ipconfig /all reported in §3.2.
4. Click OK. Windows may prompt to allow; click Allow access.
5. Click Diagnostics > Test. The expected result is OK for both Read and Write on the selected interface.

5. Solution Path C — Repair the Winsock Catalog

If the NIC is visible to Windows but PST still reports none, reset the Winsock catalog. This is a non-destructive operation; it rewrites the LSP database and re-registers base Winsock providers.

1. Open Command Prompt (Admin).
2. Run netsh winsock reset. A reboot is required.
3. After reboot run netsh int ip reset to rebuild the IP interface table.
4. Confirm with netsh winsock show catalog that the expected TCP/IP provider is present.
5. Re-open PST. The combo box should now enumerate the NIC.

6. Solution Path D — Verify the NetworkCards Registry Tree

When Steps 3 and 5 succeed but PST still shows nothing, validate the registry enumeration that PST uses internally. Microsoft documents this path in Network Adapters Not Displayed in Advanced Network Settings.

1. Run regedit as Administrator.
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards.
3. Confirm that sub-keys exist for each physical NIC. Each sub-key contains Description (REG_SZ) and ServiceName (REG_SZ) entries that point to the matching driver service key under HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Adapters.
4. If a NIC is missing, the device is registered at the driver level but the NetworkCards enumeration is corrupted. Repair by right-clicking the affected NIC in Device Manager, choosing Uninstall device (check Attempt to remove the driver for this device), rebooting, and letting PnP re-enumerate the card. Windows re-creates the NetworkCards entry on the next boot.

7. Solution Path E — Reinstall or Repair the Primary Setup Tool

When the NIC is fully functional but the PST profile is corrupted, a clean reinstall resolves the issue. This was the original escalation path that closed the field case.

1. Close all Siemens applications.
2. Open Control Panel > Programs and Features.
3. Locate Siemens SIMATIC Primary Setup Tool (or STEP 7 Micro/WIN SMART). Right-click → Uninstall.
4. Delete residual profile folders:
   • %APPDATA%\Siemens\Primary Setup Tool
   • %PROGRAMDATA%\Siemens\Automation\PST
   • %LOCALAPPDATA%\Siemens (PST subtree only)
5. Reinstall from the original media or download the current version from the Siemens Industry Online Support portal. Confirm the installer is Run as administrator.
6. Reboot. Launch PST. The NIC list is now re-populated from the live OS enumeration.

8. Verification Procedure

After applying any of the solutions above, validate the fix end-to-end.

1. Open PST and select Communications. The NIC must appear in the combo box.
2. Click Find CPUs (or Browse). The S7-200 SMART CPU on the same subnet must appear with its IP and MAC.
3. Select the CPU and click OK. PST should connect and load the project tree.
4. From the same host, ping the CPU: ping 192.168.0.1 (default S7-200 SMART IP). A 1 ms response confirms the L3 path.
5. Run Set PG/PC Interface > Diagnostics > Test. A green OK on both Read and Write confirms the Siemens access point is bound to the correct physical interface.

9. Preventive Checklist

• Document the access point binding. After every PG/PC Interface change, screenshot the dialog and store it in the project folder.
• Disable third-party security suites only during the first install of PST. Some endpoint protection products block the UDP discovery port 2366 used by the S7-200 SMART CPU. Allow PST.exe through the firewall.
• After every major Windows feature update, run netsh winsock reset and re-validate PST discovery. This is a 30-second insurance policy.
• Avoid removing the TCP/IPv4 protocol from any physical NIC. Static addressing is achieved inside the IPv4 properties, not by removing the protocol.
• Keep the S7-200 SMART firmware and PST version matched. Refer to the compatibility list in the Siemens Industry Online Support portal for the S7-200 SMART CPU entry.

10. Quick-Reference Recovery Matrix

FAQ