Resolving Missing Status Displays and Font Corruption in Drive Faceplates on Specific OS Clients

When drive faceplates fail to display operating status or render corrupted characters (such as '????') on one specific OS Client station (OS01) while functioning normally on all other clients, the defect is localized to the client operating system environment rather than the PCS 7 multiproject. The primary causes are unregistered WinCC ActiveX/OCX faceplate controls, mismatched Windows System Locale (non-Unicode language) settings, or missing Windows user group permissions. To resolve this, execute 'Register-DLL.bat' from the WinCC bin folder as Administrator, align the Windows Region and Language settings with healthy client OS02, ensure the user belongs to the local 'SIMATIC HMI' group, and restart OS01.

Diagnostic Localization: Client-Specific vs Project-Wide Faults

In a multi-station SIMATIC PCS 7 environment (Engineering Station, redundant OS Servers, and multiple OS Clients), establishing the boundary of failure is the first diagnostic step:

If drive faceplates fail on all stations, the defect lies in the AS technological block, CFC compilation, or OS server package.
If drive faceplates function perfectly on OS02 but fail exclusively on OS01, the project data, AS logic, and server packages are 100% healthy. The issue resides strictly in the local operating system, runtime libraries, or user permissions of workstation OS01.

Root Causes: Unregistered OCX Controls vs Regional Locale Mismatch

Two distinct local anomalies typically cause blank or corrupted faceplate displays on isolated clients:

Unregistered WinCC ActiveX / OCX Controls: Standard APL drive faceplates (@PG_MotL.pdl, @PG_MotRevL.pdl) utilize specialized WinCC controls (such as CCAxControl, SIF_APL.ocx, and FaceplateControls.ocx) to render status words, mode badges, and operating buttons. If anti-virus software quarantined or failed to register these controls during client setup, the container picture window opens, but the status pane remains completely blank.
Windows System Locale / Language Mismatch ('????' Text): If static labels or dynamic text display as question marks (????), the Windows Language for non-Unicode programs (System Locale) on OS01 differs from the engineering station. For example, if the project text library was compiled under German (Germany) or English (United States), but OS01 is set to an unsupported international locale, the WinCC font subsystem cannot map string character encodings.

Why Copying WinCC Projects Between Clients Fails to Fix OS01

Copying the WinCC project directory from healthy OS02 to OS01 does not resolve the issue because:

The project folder contains only project-specific files (graphics .pdl, server references .pck).
It does NOT contain the Windows OS system registry entries, DLL/OCX binary registrations, or Windows user group policies responsible for rendering faceplate controls.

Step-by-Step Remediation Workflow for OS01

Follow this sequence directly on workstation OS01:

Re-Register WinCC COM and OCX Controls:
- Open an elevated Command Prompt (Run as administrator).
- Navigate to C:\Program Files (x86)\Siemens\WinCC\bin.
- Execute Register-DLL.bat.
- Ensure all registrations report DllRegisterServer in ... succeeded.
Harmonize Windows Regional and Language Settings:
- Open Windows Control Panel > Clock and Region > Region.
- Open the Administrative tab and click Change system locale....
- Ensure the System Locale matches OS02 (e.g. English (United States)).
- Uncheck the beta option Use Unicode UTF-8 for worldwide language support if present.
Verify Windows Security Group Memberships:
- Open Computer Management (compmgmt.msc) -> Local Users and Groups > Groups.
- Confirm the logged-on user account is an active member of SIMATIC HMI and SIMATIC NET.
Restart Workstation: Restart OS01 to reload system fonts, registry hives, and DCOM security tokens.

Troubleshooting Matrix for Client Faceplate Rendering Failures

The table below details diagnostic symptoms and remedies on isolated OS clients:

Observed PhenomenonUnderlying Root CauseVerification MethodCorrective Engineering ActionFaceplate status area blankUnregistered SIF_APL.ocx controlCheck Windows registry on OS01Run Register-DLL.bat as AdministratorText displays as '????'Windows System Locale mismatchCheck Administrative Region tabAlign system locale with ES and rebootFaceplate displays 'No Connection'DCOM security / missing SIMATIC HMIInspect Event Viewer security logAdd user to SIMATIC HMI groupDistorted or clipped buttonsWindows Display DPI scaling > 100%Check Windows Display SettingsSet display scaling strictly to 100%Faceplate fails to open entirelyMissing GraCS pictures on clientCheck <OSC_Proj>\GraCSPerform Target OS Client Download from ES

Verification

Verify normal drive faceplate operation on OS01:

Launch WinCC OS Runtime on OS01.
Click a drive block icon (motor or valve) on an operational process screen.
Confirm that the faceplate window opens cleanly without blank areas or '????' text.
Verify that drive status indicators (Auto/Manual mode, Running/Stopped status, Interlock badges) display accurately.
Compare the visual rendering side-by-side with OS02; verify identical appearance and font clarity.

Limitations and Operational Precautions

Observe the following safeguards when administering OS clients:

Administrative Privileges: Running registration scripts and modifying Windows system locales requires local Administrator privileges.
Standardized Master Image: Use standardized IT master deployment images (or Siemens IPC Restore USBs) across all OS clients to prevent workstation-to-workstation software divergence.
Anti-Virus Exclusions: Ensure that Siemens-recommended anti-virus exclusions (excluding WinCC\bin and project paths) are configured in corporate endpoint protection agents.

Engineer FAQ

Why didn't copying the working WinCC project from OS02 fix OS01?

Because faceplate rendering relies on locally installed Windows operating system components, system font character sets, and registered WinCC ActiveX/COM controls in the Windows registry, which are not stored inside the WinCC project directory.

What causes text to appear as '????' in WinCC faceplates?

Question marks indicate that the Windows non-Unicode System Locale on the client cannot interpret the character encoding of the text library strings compiled on the Engineering Station.

What does Register-DLL.bat do?

Register-DLL.bat executes regsvr32 commands across all proprietary WinCC DLL and OCX components located in WinCC\bin, restoring broken COM registrations in the Windows registry.