Resolving Blank White Screen on Maintenance Station System Overview in PCS 7 Web Navigator

In SIMATIC PCS 7 Web Navigator, encountering a blank white screen when opening the Maintenance Station System Overview picture (@MaintenanceStation.pdl or @Overview1.pdl) on a web client—while all other process graphics render correctly—indicates that the specialized Maintenance Station ActiveX controls are missing on the client or failed during Web View publishing. The System Overview relies on CCMaintenanceControl.ocx and complex diagnostic scripts. To resolve this, run the Web View Publisher on the Web Server with 'Convert all pictures' selected, verify that the Maintenance Station plug-in is deployed to the web client, and add the Web Server URL to Internet Explorer's Trusted Sites with ActiveX execution permitted.

Maintenance Station Web Architecture and ActiveX Controls

The SIMATIC PCS 7 Maintenance Station (MS) provides centralized plant asset management and hardware diagnostics integrated directly into WinCC. The primary diagnostic graphic—the System Overview (@MaintenanceStation.pdl / @Overview1.pdl)—displays the entire distributed hardware topology (AS controllers, redundant fieldbus networks, distributed I/O racks, and IPCs) using dynamic status rings and maintenance state icons.

When publishing the WinCC project for thin-client access via SIMATIC WinCC Web Navigator, standard WinCC shapes (rectangles, text, trends) are converted into optimized web graphics. However, the Maintenance Station System Overview is not a standard static graphic; it utilizes specialized WinCC ActiveX controls—primarily CCMaintenanceControl.ocx and pdl_ocx—to dynamically build the diagnostic tree at runtime. For a web client to display this screen, both the converted web data files and the client-side ActiveX components must be fully registered and permitted by Windows security.

Root Causes of Blank White Viewports on Web Clients

When a Web Navigator client displays a blank white screen upon navigating to the System Overview, technical investigation identifies four root failure modes:

Missing or Blocked ActiveX Plug-in on the Web Client: Unlike local OS stations where Siemens software packages are natively installed, Web Navigator clients operate through a web browser. If the client PC has not installed the PCS 7 Maintenance Station Web Plug-in, or if browser security zones block unsigned/unverified ActiveX controls, Internet Explorer cannot render the control container, presenting an empty white viewport.
Incomplete Web View Publishing on the Web Server: During initial deployment or after virtualizing the physical Web Server, the Web View Publisher wizard was executed with 'Convert changed pictures only' rather than 'Convert all pictures'. Consequently, the @MaintenanceStation.pdl graphic was omitted or corrupted during translation into web data.
DCOM and User Group Permissions on Virtualized Web Servers: Virtualizing a physical Web Server often modifies virtual network adapter identifiers. If the WebNavigator user lacks access to the WinCC diagnostic share (WinCC_Diagnose) or SIMATIC DCOM objects, diagnostic scripts fail silently.
Internet Explorer 11 Compatibility Mode and Enhanced Protected Mode: On Windows 10 web clients, 64-bit Enhanced Protected Mode (EPM) in Internet Explorer blocks 32-bit WinCC ActiveX controls from launching.

Web Navigator Components and Publishing Requirement Matrix

The following table summarizes the required components, client plug-ins, and security settings for Maintenance Station web display:

ComponentLocationRole in System Overview DisplayRemediation ActionCCMaintenanceControl.ocxWeb Client / Web ServerCore ActiveX control rendering diagnostic treeInstall via Web Client Plug-in pageWeb View PublisherWeb Server (WinCC Explorer)Converts @MaintenanceStation.pdl for webRun wizard with 'Convert all pictures'IE Security ZoneWeb Client BrowserAuthorizes ActiveX executionAdd server to Trusted Sites (Low-Medium)Enhanced Protected ModeWeb Client (IE Advanced)Blocks 32-bit legacy ActiveX controlsDisable EPM in Internet ExplorerWebNavigator User GroupWeb Server (Local Users)Grants access to web runtime sharesAdd user to SIMATIC HMI & WebNavigator

Step-by-Step Procedure to Restore System Overview on Web Clients

To resolve the blank white screen and restore the System Overview on Web Navigator clients:

Re-publish Web Graphics on the Web Server:
- On the PCS 7 Web Server, open the WinCC OS project in WinCC Explorer.
- Right-click Web Navigator and select Web View Publisher.
- Select Convert all pictures (do not select 'Convert changed pictures only').
- Ensure that all @MaintenanceStation*.pdl and @Overview*.pdl files are checked in the picture list.
- Complete the publishing wizard and confirm that 100% of files publish without conversion errors.
Install Maintenance Station Web Plug-in on the Web Client:
- On the client PC, open Internet Explorer (32-bit mode).
- Browse to the Web Server home page: http://<WebServer_IP_or_Name>/.
- Click the link Download Plug-Ins.
- Locate and download the PCS 7 Maintenance Station Client Plug-in (and standard Web Navigator client package).
- Run the installer as Administrator and complete installation.
Configure Internet Explorer Security and Compatibility Settings:
- In Internet Explorer, open Tools -> Internet Options.
- Under the Security tab, select Trusted Sites and click Sites.
- Add http://<WebServer_Name> (uncheck 'Require server verification https').
- With Trusted Sites selected, click Custom level....
- Enable: 'Download signed ActiveX controls' and 'Run ActiveX controls and plug-ins'.
- Switch to the Advanced tab; scroll to Security and uncheck Enable Enhanced Protected Mode.
Test Navigation in Web Navigator:
- Restart Internet Explorer and log into Web Navigator.
- Click the System Overview button in the picture tree.
- Confirm that the diagnostic topology tree renders cleanly with active diagnostic state icons.

Verification

Verify Maintenance Station web access:
1. In the Web Navigator client, navigate to the System Overview; verify that all AS controllers, CP cards, and ET 200M stations display with colored health rings (green = OK).
2. Click a controller rack icon; verify that the detailed rack view opens showing slot-level module states.
3. Simulate an I/O wire break in a test rack; confirm that the Web Navigator client reflects the maintenance alarm symbol within 3 seconds.
4. Check the client diagnostic log (C:\Program Files (x86)\Siemens\WinCC\Webnavigator\Client\diagnose.log); confirm zero ActiveX instantiation exceptions.

Limitations and Operational Precautions

Browser Compatibility Boundary: WinCC Web Navigator and Maintenance Station ActiveX controls require Internet Explorer 11 (or Microsoft Edge in IE-Mode). Chrome, Firefox, and native Edge do not support ActiveX.
Web Server Resource Allocation: When virtualizing a Web Server, allocate at least 4 vCPUs and 8 GB RAM to ensure smooth graphic conversion and client session handling.
Commercial Accuracy Disclaimer: Verify Web Navigator client licensing entitlements (6AV6371-...) in Automation License Manager on the central Web Server.

Engineer FAQ

Why does the System Overview show white on Web Navigator but works in local WinCC?

The local WinCC station has all PCS 7 Maintenance Station ActiveX controls pre-installed. The web client PC lacks the required CCMaintenanceControl.ocx plug-in.

Can I use Microsoft Edge to view the PCS 7 System Overview?

Yes, but Edge must be configured in 'Internet Explorer Mode' (IE-Mode) with Enterprise Mode Site Lists to allow ActiveX execution.

Where do I download the Maintenance Station Web Plug-in?

Web clients download plug-ins directly from the Web Server's default landing page under the 'Download Plug-Ins' link.

Why did publishing fail on the virtualized Web Server?

Virtualization may change computer names or user permissions. Rerun the WinCC Web Configurator to establish fresh IIS application pool bindings.

Technical References

Related Tags

Maintenance Station
Web Navigator
System Overview
ActiveX
CCMaintenanceControl
White Screen

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Resolving Blank White Screen on Maintenance Station System Overview in PCS 7 Web Navigator