Fixing Black APL Faceplates and Missing Color Palettes in PCS 7 WinCC Runtime

APL faceplates and block icons render with solid black backgrounds in WinCC Runtime when the OS project's central design palette lacks the standardized Advanced Process Library (APL) color palette. In PCS 7 V9.x, faceplate screens (e.g., PG_MotL_Standard.pdl) reference dynamic palette color indices rather than static RGB values; if the palette is uninitialized, the index evaluates to 0 (black). To restore faceplates, open the OS Project Editor in WinCC Explorer, select 'Update palette colors of Advanced Process Library', and execute 'Complete configuration'.

Color Palette Architecture in PCS 7 Advanced Process Library

In modern SIMATIC PCS 7 systems (V8.x, V9.x, and V9.1), the Advanced Process Library (APL) utilizes an indexed central color management system. Rather than hard-coding static RGB color codes into hundreds of faceplate graphic files (PG_*.pdl) and block icon scripts (@PCS7Typicals*.pdl), objects reference dynamic palette color indices.

This design enables:
* Uniform theme switching (e.g., standard industrial gray, high contrast, or dark mode).
* Compliance with ergonomic standards (such as ISA-101 and NAMUR NE107).
* Consistent color representation for operational states across all motor, valve, analog, and sequence blocks.

These colors are stored inside the WinCC Project Palette file (APL_ColorPalette.xml) and registered in WinCC Explorer under Computer Properties -> User Interface and Design -> Palette.

Root Cause of Solid Black Faceplates and Missing Palettes

When an engineer generates a new OS project or migrates a project across PCS 7 versions, faceplates (such as PG_MotL_Standard.pdl) can render completely black:
1. Uninitialized Project Palette: If the OS was created as a standalone WinCC project outside the PCS 7 wizard, or if the initial project editor run failed, the project database contains only default classic WinCC colors. The specific Advanced Process Library Palette is entirely absent.
2. Palette Index Evaluation Failure: When an APL faceplate opens in runtime, its graphic shapes query the missing APL color index. Because the index cannot be resolved, WinCC defaults to color integer value 0, which evaluates to RGB (0, 0, 0)—rendering the faceplate background, tabs, and status areas solid black.
3. System PDL Discrepancy: Opening the system PDLs in Graphics Designer directly reveals black backgrounds because the development environment also cannot locate the referenced APL palette definition.

Step-by-Step Restoration Procedure

To inject the standard APL color palette and restore correct faceplate rendering:

Launch OS Project Editor:
* Open the affected OS project in WinCC Explorer.
* In the navigation tree, double-click OS Project Editor.
Configure Palette Update Options:
* In the OS Project Editor dialog, select the Basic Data tab.
* Under the Update palette colors section, ensure the check box Update palette colors of Advanced Process Library is selected.
* Under configuration options, select Complete configuration (no changes possible). This forces the editor to reconstruct all standard PCS 7 template graphics and palette definitions.
Execute Configuration Run:
* Click OK.
* The editor extracts standardized APL graphics, updates the @ system screens, and imports the master APL_ColorPalette.xml into the WinCC project directory.
Verify Project Palette Registration:
* Right-click the computer icon in WinCC Explorer and select Properties.
* Go to User Interface and Design.
* Confirm that the Advanced Process Library palette appears in the palette drop-down menu with all standard gray, blue, green, and alarm color swatches populated.

Verification

In WinCC Graphics Designer, open PG_MotL_Standard.pdl. Confirm that the background now renders in the standard industrial soft gray tone rather than solid black.
Launch WinCC Runtime.
Click on a motor or valve block icon to open its faceplate.
Confirm that the faceplate header, control buttons, status indicators, and analog trend tabs display proper contrast, crisp typography, and standard APL color styling.

Limitations and Operational Precautions

Executing a "Complete configuration" in the OS Project Editor will overwrite any customized files prefixed with @ in the GraCS directory. Ensure custom screens are backed up or properly named without @.
If the project structure itself has corrupted database tables (e.g., from an aborted OS migration), creating a fresh SIMATIC PC Station in SIMATIC Manager and compiling the OS cleanly may be required.
Ensure that the installed PCS 7 APL version matches the installed WinCC version. Never install older APL library versions (e.g., V8.2) on top of newer PCS 7 systems (e.g., V9.1 SP1).

Engineer FAQ

Why did the faceplates work in another project on the same VM?
The other project was created using the standard PCS 7 Multiproject Wizard, which automatically initializes the APL palette during project creation, whereas the broken project missed the initial OS Project Editor execution.
Does separating the AS and OS into different projects in a multiproject cause black faceplates?
No. Storing AS and OS stations in separate user projects within a multiproject is standard Siemens engineering practice for large systems and has no impact on WinCC palette management.
Can I manually import the APL color palette XML file?
Yes. In WinCC Explorer -> Computer Properties -> User Interface and Design, you can use the palette import feature to import APL_ColorPalette.xml directly from the PCS 7 installation directory.

Technical References

SIMATIC PCS 7 Advanced Process Library (APL) Function Manual (A5E43360408-AA).
SIMATIC PCS 7 OS Process Control System; Graphic Objects and Faceplates Manual.
Siemens Industry Online Support Entry ID 109801081: Restoring APL Color Palettes in WinCC Runtime.