Resolving LOGO! 8 to WinCC Runtime Advanced Communication Failure in TIA Portal V13

Establishing a stable Ethernet connection between a Siemens LOGO! 8 (firmware FS:04) and WinCC Runtime Advanced under TIA Portal V13 frequently fails on first integration. The runtime may start, the alarm log may show repeated connect/disconnect events, and tag values stay at their initialization value (typically 0). In nearly every case, the engineering workstation, not the LOGO! 8 hardware, is the source of the fault. This reference isolates the precise settings that must be applied on the PC, in the TIA project, and on the LOGO! 8 BM so that an S7 connection can be established and verified end-to-end.

1. Problem Description

Engineers integrating a LOGO! 8 logic module (6ED1052-1xxxx-xxxx series) with WinCC Runtime Advanced V13 typically report one of the following symptoms:

• The WinCC Runtime starts, the connection icon stays red or toggles between green and red.
• The HMI alarm log shows connection establishment and immediate termination, repeating at the configured polling interval.
• Output bits commanded from the HMI tags never change state on the LOGO! 8 outputs.
• The TIA Portal download to the LOGO! 8 works correctly, which confirms the Ethernet link itself is functional at Layer 2/3.

Because the TIA download path uses the same Ethernet cable and IP subnet as the HMI runtime, the failure is not a Layer 1 (cable, switch, port) or Layer 3 (subnet) fault. The root cause sits on the engineering PC in one of three places: the PG/PC interface assignment, the Windows firewall, or the privilege level under which the runtime is launched.

2. Affected Versions and Components

3. Root Cause Analysis

Four independent failure modes are commonly observed. Each must be eliminated before the next is investigated.

3.1 PG/PC Interface set to the wrong network adapter

The Windows S7ONLINE access point routes all S7 communication originated by Siemens applications (TIA Portal, WinCC Runtime Advanced, LOGO! Soft Comfort online) through one specific network interface. If the access point is bound to a wireless adapter, a Hyper-V virtual switch, or a disabled NIC, the runtime cannot open a TCP connection to the LOGO! 8 even though TIA Portal may appear to download successfully using a different route. The correct assignment on a single-LAN engineering PC is Ethernet TCP/IP (Auto) or Ethernet TCP/IP -> <your Intel/Realtek NIC>.

3.2 Windows Firewall blocks port 102

S7 communication uses ISO-on-TCP (RFC 1006) on TCP port 102. The Windows Firewall, particularly under a corporate domain policy, blocks inbound and outbound traffic on this port for non-authenticated processes. The runtime process CCRTAdvanced.exe is not pre-authorized in most Windows installations.

3.3 Runtime not launched with administrator rights

WinCC Runtime Advanced requires read and write access to several registry keys under HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\Automation\ and to the project storage folder. When launched as a standard user on a UAC-enabled system, the runtime silently fails to initialize the S7 channel driver and reports the connection state as "disconnected" without a meaningful error code.

3.4 Server connection not enabled in the LOGO! program

In LOGO! Soft Comfort, the Ethernet connection used by S7 communication is configured as a server connection. If no server connection is defined, or if the connection is configured as a client targeting a non-existent peer, the LOGO! 8 will accept TIA Portal downloads (which use a separate protocol on port 8080) but will reject the S7 connection request on port 102 from the runtime.

4. Solution A - Configure the PG/PC Interface

The PG/PC interface is the single highest-impact correction.

1. Close TIA Portal and any active WinCC Runtime instance.
2. Open Control Panel → Set PG/PC Interface (German: PG/PC-Schnittstelle einstellen).
3. In the Access Point of the Application dropdown, select S7ONLINE.
4. In the Interface Parameterization Used list, choose Ethernet TCP/IP (Auto) if only one physical NIC is active, or select the specific Intel/Realtek/Broadcom NIC that is cabled to the LOGO! 8 switch.
5. Click OK and confirm the dialog warning about overwriting the access point.
6. Reopen TIA Portal. The download and online dialogs will now use the assigned NIC.

5. Solution B - Verify IP Addressing

Both the LOGO! 8 BM and the engineering PC must reside in the same IP subnet with matching subnet masks. The default values for a LOGO! 8 are 192.168.0.10 / 255.255.255.0. The default gateway is left empty for point-to-point integration.

Set the LOGO! 8 IP through LOGO! Soft Comfort → Tools → Transfer → Ethernet Connection or directly via the LOGO! onboard display (ESC → OK → Network → IP Address). Disable any secondary virtual adapters (Hyper-V, VirtualBox host-only, VMware) before the test to eliminate asymmetric routing.

6. Solution C - Firewall and Runtime Privilege

1. Open Windows Defender Firewall with Advanced Security and inspect Inbound Rules for entries containing Siemens. Enable the rules for CCRTAdvanced.exe and S7DOS if present.
2. If no Siemens rule exists, create a new Inbound Rule allowing TCP port 102 for the profile matching the corporate network (Domain, Private).
3. Right-click the WinCC Runtime Advanced shortcut and select Run as administrator. For permanent elevation, open the shortcut properties → Compatibility → check Run this program as an administrator.
4. Repeat the test. The connection should establish within 2-3 seconds of runtime start.

7. LOGO! 8 Ethernet Connection Configuration

In LOGO! Soft Comfort, the S7 server connection must be explicitly created. The LOGO! 8 supports one active S7 server connection; additional partners are rejected.

1. Open the LOGO! program in LOGO! Soft Comfort.
2. Select Tools → Ethernet Connections.
3. Click Add and configure:
     - Connection type: S7 Connection
     - Local TSAP: 02.00 (default for LOGO! 8 server)
     - Remote TSAP: 03.01 (must match the HMI connection partner)
     - Remote IP: leave blank or specify the engineering PC IP to restrict access
4. Transfer the modified program to the LOGO! 8 BM and cycle power if the LOGO! requests a restart.

7.1 VM address mapping for LOGO! variables

LOGO! 8 exposes its process image through fixed VM addresses. Map your tags accordingly in WinCC:

For output control from WinCC, the HMI must write to the corresponding network input VM area in the LOGO! program, not directly to the Q area. Define a network input in LOGO! Soft Comfort and reference it in your FBD logic; the HMI then writes to that VM address which the LOGO! application routes internally.

8. WinCC RT Advanced Connection Setup

In the TIA Portal project, add the LOGO! 8 BM as a partner under HMI tags → Connections.

1. In the project tree, expand the HMI device and open Connections.
2. Double-click the existing connection (or add a new one) and configure:
     - Communication driver: S7-300/400/LOGO!
     - Partner (PLC): LOGO! 8 BM
     - Interface: PROFINET/Ethernet
     - Partner IP address: 192.168.0.10
     - Partner TSAP: 02.00 (must match the LOGO! server TSAP)
     - Local TSAP: 03.01
3. Compile the HMI project and start the runtime.

9. TIA Portal V13 Project Configuration

For the runtime to find the project at startup, the compiled RT file must be loaded into the configured runtime storage path:

1. Right-click the HMI device → Compile → Software (rebuild all).
2. Right-click → Start Runtime. TIA V13 will transfer the project to the local runtime directory and launch it.
3. For autostart, configure the runtime under HMI device → Runtime settings → Autostart.

The project file is stored under %ProgramFiles%\Siemens\Automation\WinCC RT Advanced\<project_name>\ by default. Verify the file <project_name>.rtf exists and has a recent timestamp matching the last compile.

10. Verification and Diagnostics

After applying the four corrections (PG/PC interface, IP subnet, firewall, server connection), verify the link in this order:

1. Ping test: ping 192.168.0.10 -t from the engineering PC. Reply time < 2 ms expected on a direct connection.
2. LOGO! Soft Comfort online test: Tools → Ethernet Connections → Go Online. The S7 connection row should show a green check.
3. Runtime status: Launch the WinCC Runtime. The connection indicator in the alarm log should turn green within 3 seconds and remain stable.
4. Tag live test: Add a WinCC tag mapped to a LOGO! flag VM address, place an I/O field on a screen, and toggle the value. The flag in the LOGO! Soft Comfort online view should change in real time.

10.1 Error code mapping

When the connection still fails, TIA Portal and the runtime produce the following hex error codes that map directly to corrective action:

10.2 Troubleshooting matrix

11. Forward Compatibility - Secure Communication (TIA V17 and later)

Beginning with TIA Portal V17, WinCC Runtime Advanced and WinCC Runtime Professional support secure communication to PLCs through X.509 certificates. The secure channel operates on top of the same TCP port 102 transport and is selected per connection in the HMI device configuration. In TIA Portal you configure the secure communication to the PLCs by means of a PLC certificate, which is generated by the TIA Portal project tree and transferred to the LOGO! along with the program. Secure communication requires a LOGO! 8 BM with firmware FS:04 or later; the configuration procedure and certificate lifecycle are documented in the official WinCC communication manual.

Secure Communication (RT Advanced, RT Professional) - WinCC / TIA Portal V20 documentation

12. Summary Checklist

• LOGO! 8 BM firmware FS:04, default IP 192.168.0.10, server TSAP 02.00.
• Engineering PC IP in the same /24 subnet, no conflicting virtual NICs.
• PG/PC interface S7ONLINE assigned to the wired Ethernet NIC.
• Windows Firewall rule allowing CCRTAdvanced.exe on TCP/102 (or firewall disabled for the test).
• WinCC Runtime Advanced started with administrator rights.
• S7 server connection defined in LOGO! Soft Comfort and transferred to the BM.
• WinCC connection partner TSAP set to 02.00, local TSAP 03.01.
• Tag address uses a LOGO! network input (NI) for write, flag (M) for bidirectional, or a digital input (I) for read-only.

With this configuration the LOGO! 8 establishes a stable S7 connection to WinCC Runtime Advanced in TIA Portal V13 within seconds, and the alarm log shows no further disconnect events.

Frequently Asked Questions