Troubleshooting LOGO! Soft Comfort Network Lag on Wireless Adapter

1. Problem Statement

Engineers report the following reproducible symptom on Windows 10 and Windows 11 engineering workstations:

• LOGO! Soft Comfort V8.x launches normally and the program editor is responsive.
• Selecting Tools → Transfer → Options or any menu that triggers a hardware probe delays the UI by 20-30 seconds.
• Disabling the wireless adapter (or the entire network stack) in Network Connections makes the latency disappear immediately.
• Re-enabling the adapter restores the delay within the same session; no LOGO! restart is required.
• CPU usage does not spike, no exception is thrown, and the LOGO! base module (LOGO! 8.FS4 or LOGO! 8.3) is reachable via ping with < 5 ms latency on the local subnet.

The fault is independent of the LOGO! firmware revision (tested on 8.FS4 firmware V1.82.01 and V1.82.02, per the Siemens LOGO! product support page), and it persists across clean reinstalls of LOGO! Soft Comfort if the conflicting Java-based utility remains installed.

2. Affected Versions and Environment

The current production release of the engineering software is documented in the Siemens LOGO! Soft Comfort V8.4 system manual (entry ID 109751419). The Java-based hardware browser inside that release still relies on javaw.exe for menu actions that touch the network stack.

3. Root Cause Analysis

LOGO! Soft Comfort shells out to a bundled javaw.exe helper whenever a menu action requires a network probe (for example: Tools → Options → Ethernet, Online → Test, or File → Properties → Hardware). The helper attempts a TCP connection to the IP and port last written into its configuration cache. The cache is shared with any other Java-based utility installed on the same workstation through a user.home properties file located at %USERPROFILE%\.siemens\logosof\connection.properties.

When a co-resident utility (Weintek pass-through, in the field-verified case) is configured for a different target IP/port — for example, 192.168.30.5:2000 for an HMI panel — the LOGO! helper inherits that entry. With the network adapter disabled, the OS returns WSAENETUNREACH (10051) almost instantly and the helper bails out. With the adapter enabled, the helper performs a full TCP SYN → SYN-ACK → RST dance against the wrong host. The retransmission timer on a closed port is governed by the TcpMaxDataRetransmissions registry value (default 5) and the initial retransmission interval of 1 second, which yields the characteristic 20-30 second hang before the menu returns control to the user.

The wireless adapter is therefore an innocent bystander. Disabling the adapter is simply the fastest way to force the helper to fail fast. The actual defect is the IP/port collision in the Java configuration cache.

4. Diagnostic Procedure

1. Reproduce the fault. Launch LOGO! Soft Comfort, connect to a LOGO! 8 base module, and open Tools → Transfer → PC ↔ LOGO!. Time the delay. A value of 20-30 s confirms this specific class of fault.
2. Capture the process tree. Open Task Manager → Details, add the Command Line column, and reproduce the menu action. Note the javaw.exe PID spawned under LOGOComfort.exe.
3. Capture network traffic. Use Microsoft Network Monitor 3.4 (legacy, still available from the Microsoft Download Center, KB 933741) or any modern equivalent such as Wireshark. Filter on tcp.port == 2000 || tcp.port == 10005 || tcp.port == 8443 and start a capture before opening the menu.
4. Inspect the destination. Identify the destination IP and TCP port. If the IP is not the LOGO! base module address (default 192.168.0.1, 192.168.1.220, or DHCP-assigned), the diagnosis is confirmed: the Java helper is targeting a foreign device.
5. Locate the conflicting utility. On the captured packet row, right-click the destination IP, choose Copy → Summary, and run netstat -ano | findstr "<PID>" from an elevated command prompt. The owning process reveals which Java-based tool registered the socket.
6. Read the configuration cache. Open %USERPROFILE%\.siemens\logosof\connection.properties in Notepad. The file is plaintext and contains entries such as target.host=192.168.30.5 and target.port=2000. Cross-check against the LOGO! module address in Tools → Options → Ethernet.

5. Resolution: Eliminating the Java/Port Conflict

5.1 Point the foreign utility at the LOGO! module

This is the field-proven fix that resolves the fault without touching LOGO! Soft Comfort at all.

1. Open the conflicting utility (for example, Weintek Pass-Through Configuration).
2. Change the target IP from the HMI panel address (192.168.30.5) to the LOGO! base module address (192.168.1.220 or whatever is set in Tools → Options → Ethernet in LOGO! Soft Comfort).
3. Leave the TCP port at the value the utility expects (2000 for Weintek pass-through, 10005 for some cMT Viewers, 8443 for HTTPS-based helpers).
4. Save and close the utility.
5. Restart LOGO! Soft Comfort to force the helper to re-read connection.properties.
6. Re-time the menu action. The delay should fall to < 200 ms.

5.2 Edit the connection.properties cache directly

If the foreign utility refuses to accept the LOGO! address, edit the cache file directly. Close LOGO! Soft Comfort first; the helper rewrites the file on every menu probe.

# %USERPROFILE%\.siemens\logosof\connection.properties
target.host=192.168.1.220
target.port=10005
protocol=TCP
timeout.ms=2000

Save the file with ANSI encoding (the helper does not parse UTF-8 BOM), re-launch LOGO! Soft Comfort, and verify.

5.3 Isolate the Java helper with a firewall rule

For permanent isolation without touching any other tool, add a Windows Defender Firewall outbound rule:

netsh advfirewall firewall add rule name="Block LOGO Helper Foreign Port" \
  dir=out action=block program="%ProgramFiles%\Siemens\LOGOComfort\jre\bin\javaw.exe" \
  remoteip=<foreign-utility-ip> remoteport=2000 protocol=tcp

This forces the helper to fail fast (sub-second) and prevents the 20-30 s TCP retransmit timer from blocking the UI.

6. Wi-Fi Adapter Optimization

Even after the Java/port conflict is resolved, a sluggish wireless link can amplify any remaining latency in the LOGO! Soft Comfort Online Test or Data Log views. The two authoritative reference points for adapter tuning are the Dell knowledge base article 000132395: Change Intel Advanced Wi-Fi Adapter Settings and the Microsoft Q&A thread My laptop randomly has slow Wi-Fi connection. Apply the following subset that is relevant to engineering workstations running LOGO! Soft Comfort.

6.1 Disable Windows Update and Store delivery optimization

Windows 10/11 uses the wireless link as the default Delivery Optimization peer. A single Windows Update in progress can starve the LOGO! helper of bandwidth. Disable delivery optimization on the engineering workstation:

1. Open Settings → Windows Update → Advanced options → Delivery Optimization.
2. Toggle Allow downloads from other PCs to Off.
3. Pause Windows Update on the engineering workstation during commissioning windows (Pause updates for 5 weeks).

6.2 Tune Intel Wi-Fi adapter advanced properties

Open Device Manager → Network Adapters → Intel Wi-Fi 6 AX200 → Properties → Advanced and set the values above. Reboot the workstation. On non-Intel adapters (Realtek, Qualcomm, MediaTek), the same property names appear with vendor-specific labels; map accordingly.

6.3 Pin the LOGO! base module to a static IP

DHCP lease churn on the wireless link can also re-trigger the Java helper timeout. Assign a static IP to the LOGO! 8 base module through LOGO! Soft Comfort → Tools → Options → Ethernet → Configure Network or directly on the LOGO! display (the procedure is documented in section 4.2 of the LOGO! Soft Comfort V8.4 system manual). Reserve the address in the DHCP server so it does not collide with the engineering laptop.

7. Verification

1. Menu timing test. Open Tools → Transfer → PC ↔ LOGO! ten times. Record the elapsed time with a stopwatch. Each menu must return control in < 1 s.
2. Network capture. Repeat the Microsoft Network Monitor 3.4 capture from Section 4. Confirm that the only javaw.exe traffic targets the LOGO! base module IP and the expected port (default 10005 for LOGO! 8).
3. Process tree. Confirm that no second javaw.exe instance is spawned. With the fix applied, only one helper PID should appear under LOGOComfort.exe.
4. Wireless latency test. From an elevated command prompt run ping -t <LOGO_IP> for 60 s while simultaneously opening menus. Round-trip times must remain < 10 ms and packet loss must be 0%.
5. Reboot test. Reboot the workstation, re-launch LOGO! Soft Comfort, and repeat the menu timing test. The fix is durable only if the timing remains < 1 s after a clean boot.

8. Prevention and Best Practices

• One engineering utility per workstation. Do not co-install Weintek EBPro, cMT Viewer, and LOGO! Soft Comfort on the same Windows profile. If unavoidable, use separate Windows user accounts (fast user switching preserves isolated %USERPROFILE% trees).
• Document the LOGO! IP in the project header. Place a comment block at the top of every LSC diagram: // Target: 192.168.1.220:10005, FW V1.82.02. This prevents a future engineer from guessing at the address and re-triggering the collision.
• Pin the wireless profile. Save the engineering SSID as a Connect automatically profile and disable Connect to suggested open hotspots in Windows. The helper fails fast when the adapter is in a known idle state.
• Schedule Windows Update outside commissioning windows. Set Active Hours to the working shift and Pause updates to 5 weeks. Re-enable updates only when the station is offline.
• Back up connection.properties. After a clean configuration, copy %USERPROFILE%\.siemens\logosof\connection.properties to the project archive. A clean restore takes seconds; diagnosing the collision takes an hour.

9. Frequently Asked Questions