Troubleshooting SFC Faceplate Opening Failures on Web Navigator Clients in PCS 7 V9.1 SP2

In SIMATIC PCS 7 V9.1 SP2 UC1 environments, SFC faceplates failing to open on WinCC Web Navigator clients—despite opening correctly on the Web Server—is caused by missing client-side SFC Visualization ActiveX plugins, incomplete web publishing of server data (@pictures), or blocked Internet Explorer / WebViewer permissions. Resolving this issue requires deploying the SFC Visualization Web Plugin from the server download page, registering active OCX controls, and verifying publication scope.

Architecture of SFC Visualization Across PCS 7 Web Navigator

Sequential Function Chart Visualization (SFV) enables control room operators to monitor step sequences, evaluate branch conditions, and acknowledge step transitions dynamically:
* On standard OS clients, SFC faceplates render via local WinCC runtime components and the installed SIMATIC PCS 7 SFC Visualization software package.
* On WinCC Web Navigator thin clients, process mimics are displayed in Microsoft Internet Explorer or the standalone WinCC WebViewer.
* To render interactive SFC diagrams, step transition matrices, and operating mode toolbars remotely, the Web Client relies on dedicated ActiveX controls (such as CSfcBlockViewer.ocx and SfcOcx.ocx) that must be installed locally on the client workstation.

Root Causes: Client Plugin Deficiencies vs. Web Publishing Scope

When SFC faceplates open smoothly on the Web Server but completely fail to respond when clicked on a remote Web Client:
* Missing SFC Visualization Web Plugin: Following an upgrade to PCS 7 V9.1 SP2 UC1, the Web Server received updated SFV binaries, but client workstations were not updated with the matching client plugins.
* Incomplete Web Publication: The Web Publishing Wizard was executed for user graphics, but system screens (@pg_sfc*.pdl, @pcs7_sfc*.pdl) and standard C-scripts were omitted from the publication package.
* ActiveX Execution Blocking: Windows security policies, User Account Control (UAC), or Internet Explorer security zones block the execution of unregistered ActiveX controls on the client PC.

Step-by-Step Recovery Procedure: Installing SFV Plugins and Re-registering OCX

To restore SFC faceplate operation on remote client workstations:
1. Access Web Server Plugin Portal:
* On the Web Client PC, open Internet Explorer or WinCC WebViewer.
* Navigate to http://<Web_Server_IP>/WebNavigator/.
* Log in using valid Windows / WinCC credentials.
2. Download and Install SFC Plugins:
* In the left-hand navigation pane, click Download Plugin.
* Locate the SIMATIC PCS 7 SFC Visualization (SFV) Web Plugin package corresponding to PCS 7 V9.1 SP2.
* Download the setup file and execute it as Administrator.
3. Manual ActiveX Registration (if automated registration fails):
* Open Windows Command Prompt as Administrator on the client PC.
* Navigate to the plugin directory (typically C:/Program Files (x86)/Siemens/WinCC/WebNavigator/Client/bin/).
* Execute manual registration commands:
cmd regsvr32 SfcOcx.ocx regsvr32 CSfcBlockViewer.ocx
* Confirm that each registration returns "DllRegisterServer in ... succeeded".

Correct Web Publishing Sequence for SFC Faceplates and Scripts

On the WinCC Web Server, ensure the SFC visualization assets are completely published:
1. Open WinCC Explorer on the Web Server and launch the Web Publishing Wizard.
2. Under Select Pictures:
* Ensure the option Publish all pictures completely is selected.
* Verify that all files starting with @pg_sfc*, @pcs7_sfc*, and @sfc* are selected.
3. Under Select Functions:
* Check all project functions, standard functions, and SFC runtime scripts.
4. Complete the wizard. The publishing engine regenerates compressed XML and zip assets in the Web Server web directory.
5. On the Web Client, clear the browser cache or delete the temporary WebViewer cache folder under C:/Users/<User>/AppData/Local/Siemens/WinCC/WebNavigator/Client/Cache/.

Verification

Launch the Web Navigator client session from the remote machine.
Navigate to a process graphic containing an active SFC block icon.
Click the SFC block icon: verify that the SFC faceplate opens smoothly within 1 second.
Verify that active steps highlight in green, transition conditions display dynamic boolean statuses, and operating buttons (Start, Hold, Resume) are enabled according to operator privileges.

Limitations and Operational Precautions

Installing client plugins requires local administrative privileges on the remote client workstation.
When upgrading the Web Server with updates or hotfixes (e.g., from SP2 to SP2 UC1), client plugins must be reinstalled to ensure binary parity between server and client.
Standard modern browsers (Google Chrome, Microsoft Edge) must run in Internet Explorer Mode or use the WinCC WebViewer application to support ActiveX components.

Engineer FAQ

Why do SFC faceplates open on the Web Server but not on remote Web Clients?
The Web Client is missing the required SFC Visualization ActiveX plugins installed locally.
Where are the Web Navigator client plugins downloaded from?
From the Web Server's integrated web download page under the 'Download Plugin' section.
What ActiveX controls are used for SFC Visualization on the Web Client?
Controls including SfcOcx.ocx and CSfcBlockViewer.ocx render the sequence graphics.
Does SFC Visualization on Web Navigator require an additional license on the client?
No, clients utilize concurrent Web Navigator server licenses; no local license is required on the client machine.
How do I clear the local cache of the WinCC WebViewer application?
Delete the contents of AppData/Local/Siemens/WinCC/WebNavigator/Client/Cache/ on the client PC.
What browser application is recommended for PCS 7 V9.1 Web Clients?
The standalone WinCC WebViewer application (WinCCWebBrowser.exe) or Microsoft Edge in IE Mode.
What happens if system pictures starting with @ are not published?
Standard faceplates and SFC pop-ups will fail to load or display missing picture errors.
Can an operator control an SFC sequence from a Web Client?
Yes, provided the user account has Process Controlling authorization in the WinCC User Administrator.
How can an engineer verify that the SFC OCX registered successfully?
Run regsvr32 from an elevated command prompt; a success dialog confirms proper registry entry.
Is an AS compile required to fix Web Client SFC opening failures?
No, this issue is strictly localized to the WinCC Web Server publishing and client-side ActiveX plugin installation.

Technical References

SIMATIC Process Control System PCS 7 Web Option for OS Manual (V9.1)
SIMATIC PCS 7 SFC Visualization (SFV) Operating Manual
Siemens Industry Online Support Entry: SFC Faceplate Behavior on Web Navigator (Entry ID 299191)
SIMATIC HMI WinCC Web Navigator Operating Instructions