Troubleshooting CEMAT Group Faceplate (C_GROUP) Opening Failures on OS Clients in SIMATIC PCS 7

When a SIMATIC PCS 7 CEMAT project (such as a cement plant application migrated from V6.0 through V7 to V8.0) allows group faceplates (C_GROUP) to open successfully on the Engineering Station and OS Servers but fails completely on OS Clients, the failure is typically caused by missing client-side CEMAT software installation, unregistered ActiveX controls, or missing CEMAT client runtime licenses. In CEMAT client-server architecture, C_GROUP faceplates rely on local OCX components (C_GROUP.OCX, CEMAT_CS) registered in the Windows operating system. If the CEMAT setup was not installed on the physical client station, or if the client lacks the mandatory CEMAT Client License (A1CEMC..), clicking group icons does not invoke the faceplate. Resolving the failure requires installing the CEMAT Client software, registering the OCX controls via regsvr32, transferring the client license via ALM, and reloading the OS Server package.

CEMAT Client-Server Architecture and Group Faceplate Dependencies

In cement, mining, and mineral facilities running the SIMATIC PCS 7 CEMAT standard, operational control is centered around technological groups (C_GROUP), routes (C_ROUTE), and drives (C_DRV_1D). When an operator clicks a group icon on an OS Client, WinCC executes a complex sequence: it reads the server tag prefix, queries the active server package, opens @PG_C_GROUP.PDL, and instantiates the C_GROUP ActiveX Control.

Unlike standard WinCC graphics that rely solely on basic shapes and native C-scripts, CEMAT relies on specialized compiled dynamic-link libraries (DLLs) and OCX components. If an OS Client was configured as a generic WinCC client without running the official CEMAT Client installation media, the necessary OCX components are missing from the client operating system.

Root Causes: OCX Registration, Local Client Files, and Licensing

Troubleshooting faceplate failures across client stations requires evaluating three distinct tiers:

Architectural TierSpecific Technical RequirementFailure Symptom on OS ClientClient Software TierC_GROUP.OCX and CEMAT_Faceplates.dll installed in C:\CEMAT_CS\Faceplate window opens completely blank or does not respond to clicksWindows Registry TierActiveX controls registered in 32-bit Windows subsystem via regsvr32Windows event log reports Class not registered (0x80040154)Licensing Tier (ALM)Active CEMAT Client License (A1CEMC..) in ALMFaceplate opens briefly and closes, or licensing warning dialog appearsServer Package TierCurrent Server Data (.pck) loaded on the OS ClientClient cannot resolve group tag references to the OS Server databaseGraphic Template Tier@PG_C_GROUP.PDL present in Server GraCS directoryWinCC reports picture file not found

Engineers frequently resolve licensing on the ES and OS Server (using server licenses A1CERT..) but overlook that CEMAT clients require independent client license keys (A1CEMC..).

Step-by-Step Procedure to Restore C_GROUP Faceplates on OS Clients

To restore full group faceplate functionality across all OS Client stations, execute the following technical workflow:

Install CEMAT Client Software: Insert the CEMAT V8.0 installation media on each physical OS Client station. Run Setup.exe and select the CEMAT Client installation package. This installs all local scripts, bitmaps, and OCX files.
Manually Register CEMAT OCX Controls (If Not Auto-Registered):
- Open an elevated Command Prompt (cmd.exe as Administrator).
- Navigate to C:\CEMAT_CS\BIN or C:\Program Files (x86)\Siemens\WinCC\bin\.
- Execute: regsvr32 C_GROUP.OCX and regsvr32 CEMAT_CS.ocx.
- Confirm that Windows reports: 'DllRegisterServer in C_GROUP.OCX succeeded'.
Transfer CEMAT Client License via ALM: Open Automation License Manager on the OS Client. Connect to the plant license server and transfer a valid CEMAT Client license (A1CEMC..) to the client's local drive C:.
Update Server Data on OS Server: On the Engineering Station, execute an OS compile. On the OS Server, generate server data via Server Data -> Generate in WinCC Explorer.
Reload Server Package on Client: On the OS Client, open WinCC Explorer. Open Server Data. Right-click the server package, select Update, or delete and re-import the .pck file.

Verification

Verify group faceplate operation on the OS Client using these diagnostic steps:

ActiveX Registration Audit: In PowerShell on the OS Client, run Get-ItemProperty HKLM:\Software\Classes\CLSID\* | Where-Object {$_.ProgID -like '*C_GROUP*'}. Confirm that the class GUID is registered in the Windows registry.
Client Faceplate Launch Test: In WinCC Runtime on the OS Client, click a C_GROUP block icon. Confirm that the faceplate opens instantly, displaying group operating modes (Automatic, Local, Single) and active interlock status.
Diagnostic Window Check: In the group faceplate, click the 'Diagnostic' button. Verify that the diagnostic sub-window renders all associated drive status bits without script errors.

Limitations and Operational Precautions

When deploying CEMAT across multi-client systems, observe these operational principles:

Version Parity Across Stations: Never mix CEMAT patch levels. If the ES and Server run CEMAT V8.0 Upd1, all OS Clients must run CEMAT V8.0 Upd1 to prevent interface collisions.
Legacy Block Compatibility: When migrating from V6.0 without updating technological blocks in CFC, ensure that the 'CEMAT Migration' faceplate templates are utilized rather than native V8 APL faceplates.
Commercial Procurement and Licensing Disclaimer: CEMAT Engineering, Server, and Client licenses are commercial add-on packages requiring valid MLFBs. Ensure distributor quotations account for every physical client terminal.

Engineer FAQ

Why did the faceplate work on the ES and Server but fail on the Client?

The Engineering Station and OS Server had the full CEMAT software suite installed (registering all OCX controls) and held server runtime licenses. The OS Client lacked local OCX registration and the dedicated CEMAT Client license.

Where is the C_GROUP.OCX file located in CEMAT?

Depending on the CEMAT version, it resides in C:\CEMAT_CS\BIN\, C:\Siemens\CEMAT\, or the WinCC bin directory.

Can I just copy the PDL pictures from the server to the client?

In a multi-client architecture, PDL pictures are referenced across the network from the OS Server package. While copying PDLs locally can work, it does not solve missing OCX registration or missing client licenses.