Troubleshooting Blank or Empty SFC Visualization Faceplates in WinCC Runtime

When an SFC Visualization faceplate opens in SIMATIC WinCC Runtime but displays a blank, empty white screen with no steps, transitions, or sequencers—while the identical project displays normally on other workstations—the fault is caused by corrupted local SFC ActiveX controls, missing @sfc system screens in the local WinCC installation, or omitted compilation options. To resolve this on the affected computer without reinstalling Windows, run the OS Project Editor in WinCC Explorer with 'Complete configuration' to restore factory @sfc*.pdl screens, re-register the SFC ActiveX controls (sfcview.ocx and sfchart.ocx) using 32-bit regsvr32, and verify that the OS compile wizard had 'SFC Visualization' enabled.

SFC Visualization Runtime Architecture and ActiveX Controls

In SIMATIC PCS 7, SFC Visualization (6ES7658-2CX58-0YH0) allows plant operators to monitor and manipulate Sequential Function Charts directly within WinCC Runtime. When an operator clicks an SFC block icon or launches an SFC faceplate (@sfc.pdl), WinCC loads a specialized container picture containing two core Siemens ActiveX controls:

SFCView.ocx: Renders the dynamic graphical state diagram (steps, transitions, active step highlights, branch paths).
SFCControl.ocx / SFChart.ocx: Manages command execution (Start, Hold, Resume, Abort, Mode selection) and coordinates interlocking conditions between the OS client and the controller.

These ActiveX controls interface directly with compiled SFC server data (.sfc / .pck) and require valid local COM DLL registrations inside the Windows system registry.

Root Causes of Blank SFC Windows on Specific Workstations

When a project displays SFCs correctly on an Engineering Station or Server, but renders a completely blank window on a specific OS Client or secondary workstation, the failure is localized to that physical client PC:

Unregistered or Damaged SFC ActiveX Controls: Software updates, security patches, or registry cleaners unregistered or corrupted the COM class identifiers (CLSIDs) for sfcview.ocx in C:\Windows\SysWOW64\.
Missing or Corrupted @sfc*.pdl System Pictures: The project's local GraCS directory contains corrupted template pictures (@sfc.pdl, @pg_sfc_standard.pdl). If the OS Project Editor was not executed locally after software installation, the local client workstation lacks the screen files matching its installed software build.
Missing OS Compile SFC Options: During AS-OS compilation on the ES, the options SFC Visualization and With interconnection partner (SFC option) must be enabled; otherwise, the compiler omits the necessary communication tags.

Comparison of SFC Visualization Diagnostics Across Workstations

The following table compares diagnostic indicators between healthy and defective SFC client stations:

Diagnostic IndicatorHealthy WorkstationDefective Workstation (Blank Screen)Fault RemediationSFC Faceplate @sfc.pdlOpens with steps and active sequencerOpens as blank white/grey boxRun OS Project Editor with @sfc selectedsfcview.ocx RegistrationSuccessfully registered in SysWOW64Unregistered or missing COM entryRe-register via 32-bit regsvr32AS-OS Compile SFC TagsTags @SFC_* present in Tag ManagementPresent on server, but client failsDownload server package to clientWinCC System Log (WinCC_Sys.log)Clean runtime executionFailed to instantiate CLSID for SFCViewRe-install SFC Visualization packageSFC Command ButtonsStart / Hold / Mode activeCompletely absent or unclickableRe-register sfchart.ocx

Step-by-Step Procedure to Restore SFC Visualization Runtime

Follow this procedure on the affected computer to resolve blank SFC faceplates without reinstalling the operating system:

Re-Register SFC ActiveX Controls:
- Open Windows Command Prompt as Administrator.
- Navigate to the 32-bit Windows system directory:
cmd cd C:\Windows\SysWOW64
- Re-register the SFC ActiveX controls:
cmd regsvr32 sfcview.ocx regsvr32 sfchart.ocx regsvr32 sfcctrl.ocx
- Confirm that each command returns: DllRegisterServer in [file].ocx succeeded.
Restore System Screens via OS Project Editor:
- In WinCC Explorer, double-click OS Project Editor (OS-Projekteditor).
- Navigate to the Basic Data tab.
- In the file list, locate all screens prefixed with @sfc (e.g. @sfc.pdl, @sfc_section.pdl). Ensure they are selected to be replaced from template.
- Click OK to execute. This copies fresh, uncorrupted system screens from the Siemens installation folder into the project GraCS directory.
Verify OS Server Package on Client:
- In WinCC Explorer on the OS Client, expand Server Data.
- Right-click the server package and select Update to refresh server pointers.

Verification

Verify SFC visualization in WinCC Runtime:
1. Start WinCC Runtime on the repaired computer.
2. Click an SFC block icon or navigate to an SFC screen.
3. Verify that the faceplate @sfc.pdl loads immediately, rendering all active steps, transitions, and sequencer flow lines.
4. Confirm that the active step is highlighted in green/blue with live elapsed step time updating second-by-second.
5. Verify that operating mode buttons (Manual, Auto) and command buttons (Start, Hold) respond cleanly to operator clicks.

Limitations and Operational Precautions

32-Bit vs 64-Bit Registry Path: WinCC Runtime executes as a 32-bit application on 64-bit Windows. Always register ActiveX controls using C:\Windows\SysWOW64\regsvr32.exe, never the 64-bit System32\regsvr32.exe.
OS Project Editor Overwrite Risk: Running the OS Project Editor replaces customized system screens. Always back up custom scripts or modified faceplate templates before running the editor.
License Verification: Verify that the station possesses a valid SIMATIC PCS 7 SFC Visualization license in Automation License Manager; missing licenses will prompt periodic demo popups.

Engineer FAQ

Why did the SFC faceplate work on one PC but show nothing on another?

The project database is intact, but the local computer had unregistered or corrupted SFC ActiveX controls (sfcview.ocx), or missing @sfc*.pdl template files in its local WinCC installation.

How do I register sfcview.ocx manually?

Open Command Prompt as Administrator, change directory to C:\Windows\SysWOW64\, and run the command regsvr32 sfcview.ocx.

What does the OS Project Editor do for SFC visualization?

The OS Project Editor copies standard Siemens system screens (including all @sfc*.pdl pictures and scripts) from the PCS 7 installation directory into the project's GraCS folder, repairing corrupted screen files.