Preventing OS Project Editor from Overwriting Customized PCS 7 Faceplates

In SIMATIC PCS 7 OS (WinCC), customized faceplate graphics (e.g. @PG_Meas_Mon.pdl, @PG_APL_OA_Analog.pdl) are overwritten by factory defaults whenever the OS Project Editor runs because the editor updates system screens from base product templates. To protect custom modifications permanently, uncheck the modified graphics under the Basic Data tab of the OS Project Editor, store customized faceplates in a dedicated project library folder, or implement custom screen prefixes instead of modifying system template files directly.

The Role and Behavior of the WinCC OS Project Editor

In SIMATIC PCS 7, the OS Project Editor is a central system wizard responsible for configuring the WinCC Operator Station shell:
* It configures screen resolutions (e.g. 1920x1080, 1680x1050, multi-monitor multi-VGA spanning).
* It generates standard navigation banners, alarm lines, message windows, and horn configurations.
* It populates the WinCC project's GraCS directory with hundreds of standardized system graphics (@Overview1.pdl, @Buttons11.pdl, @AlarmOneLine.pdl) and library faceplates.

Whenever an engineer updates screen resolutions, changes monitor layout, or updates library versions, running the OS Project Editor is mandatory. However, by default, the wizard assumes all system files starting with @ belong to the factory distribution, systematically replacing existing project files with pristine copies from the Siemens software installation directory.

Why OS Project Editor Overwrites Custom Faceplates

Engineers frequently open standard faceplates—such as @PG_Meas_Mon.pdl (Classic library measured value monitor) or @PG_MonAnL.pdl (APL analog monitor)—in WinCC Graphics Designer to add custom customer branding, auxiliary trend buttons, or special interlocking notes.

After saving the modified file in \GraCS\:
1. The faceplate operates perfectly during immediate testing.
2. Weeks later, an engineer runs OS Project Editor to adjust alarm horn settings or screen resolution.
3. Upon opening the faceplate in runtime: All custom changes have vanished, replaced by the default factory design!
4. Root cause: In the OS Project Editor dialog, under the Basic Data tab, every standard system graphic has an active checkmark indicating that the file should be synchronized from the system template cache.

Anatomy of APL Faceplate Architecture in Graphics Designer

In the Advanced Process Library (APL), faceplates are modular composite structures rather than single monolithic screens:
* @PG_<BlockType>.pdl (Main Frame): The parent window providing the header bar, operating mode buttons, view selection tabs, and alarm banner.
* @PG_<BlockType>_Standard.pdl (Standard View): The default operational view displaying primary process values, setpoints, bar graphs, and manipulated variables.
* @PG_<BlockType>_Limit.pdl (Limit View): Displays alarm, warning, and tolerance limit configurations.
* @PG_<BlockType>_Trend.pdl (Trend View): Contains the embedded WinCC OnlineTrendControl plotting historical values.
* @PL_<BlockType>.pdl (Block Icon Callback): Intermediate layer managing tag prefix passing.

Knowing which component of the faceplate contains your custom graphics is vital for targeted protection.

Faceplate Customization and Protection Strategy Matrix

The following matrix compares methods for preserving customized faceplates in SIMATIC PCS 7:

Protection StrategyEffort RequiredSafety Across OS Project EditorSafety Across PCS 7 UpgradesDirect Edit in \GraCS (No Protection)LowestZero (Overwritten immediately)Zero (Overwritten)Uncheck in OS Project Editor Basic DataLow (Single dialog check)100% ProtectedRequires verification after upgradeDedicated Custom Faceplate PrefixesModerate (Script modifications)100% Protected (Never touched)100% Protected across versionsUser Typicals and Custom APL ViewsAdvanced100% Protected (Siemens Standard)Highest Stability

Step-by-Step Procedure to Protect Custom Faceplates

Follow this standardized procedure to protect customized faceplates from being overwritten:

Method 1: Uncheck Files in OS Project Editor (Recommended for Minor Modifications)

Open WinCC Explorer.
In the navigation tree, double-click OS Project Editor.
Navigate to the Basic Data tab.
In the table of system files, expand the list and locate the modified faceplate graphics (e.g. @PG_Meas_Mon.pdl or @PG_MonAnL_Standard.pdl).
Uncheck the checkbox next to each modified file.
- An unchecked box instructs the wizard: 'Preserve the existing file in the project \GraCS directory; do NOT copy from template'.
Click OK to execute the editor.

Method 2: Configure a Custom View in APL Block Properties

If adding an entirely new customized view (e.g. a specialized calibration tab):
1. In \GraCS\, create a new graphic named @PG_<BlockType>_Custom.pdl.
2. In the parent frame @PG_<BlockType>.pdl, assign the custom view to one of the user-definable view tabs.
3. Because @PG_<BlockType>_Custom.pdl does not exist in the factory Siemens library, OS Project Editor will never attempt to overwrite it.

Verification

Verify that customized faceplates survive OS Project Editor runs:
1. Make a visible benign modification to the custom faceplate (e.g. add a static text label [CUSTOM VERIFIED] in Graphics Designer).
2. Save the file.
3. Open OS Project Editor: Ensure the modified file is unchecked in Basic Data. Click OK to run the complete editor synchronization.
4. Open the faceplate in Graphics Designer and WinCC Runtime:
- Confirm that the [CUSTOM VERIFIED] label remains intact.
- Confirm that faceplate dynamics, script calls, and tag prefixes continue functioning normally.

Limitations and Operational Precautions

Unchecking files in OS Project Editor prevents those files from receiving official Siemens bug fixes or security patches included in library service packs; review custom faceplates manually after major library upgrades.
Never rename standard APL tag prefixes or script function calls within a faceplate; modifying core APL script logic can break process alarm acknowledgment.
Always maintain an offline backup directory of all customized .pdl graphics outside the WinCC project folder.

Engineer FAQ

Why did my modified file not appear in the Basic Data list of OS Project Editor?

Only files that exist in the factory Siemens template directory (<PCS7_Install_Path>\WinCC\options\pdl\base_data_pdl\) appear in the Basic Data list. If you created a brand-new file with a custom name, it is already automatically safe from OS Project Editor.

Can I customize the color scheme of standard APL faceplates?

Yes. APL faceplate color schemes are driven by global color palettes and central script headers (@APLColorPalettes.pdl). Customizing color palettes centrally alters all faceplates without modifying individual .pdl files.

What happens if I accidentally run OS Project Editor with my files checked?

The editor overwrites your customized files with factory defaults. The original files cannot be restored unless you have an offline backup or shadow copy.