Managing System '@' Pictures in SIMATIC PCS 7 WinCC: OS Project Editor Regeneration vs Custom GrACS Preservation

In SIMATIC PCS 7 WinCC, graphic files beginning with '@' (such as @SCREEN.PDL, @TOP.PDL, and @Overview1.pdl) are standard system pictures generated by the OS Project Editor and reside physically in the OS project's GraCS subfolder. They are hidden by default from the SIMATIC Manager project tree to prevent accidental alteration. If '@' pictures are missing or corrupt, running the OS Project Editor regenerates them to factory defaults. However, running the OS Project Editor with default settings will overwrite any custom script or layout modifications made to @ pictures; to preserve custom work, use the OS Project Editor 'Complete Configuration' options with selective file overwrite rules or backup customized files first.

Architecture of WinCC '@' System Pictures in SIMATIC PCS 7

In SIMATIC PCS 7, the human-machine interface adheres to a standardized plant visualization model defined by the OS Project Editor. Rather than building process screens and navigation bars from a blank canvas, PCS 7 utilizes a modular screen hierarchy where the main operating desktop is divided into functional frames:

@TOP.PDL: Top navigation bar containing area selection buttons, plant overview navigation, and operator messages.
@SCREEN.PDL: The root layout container that embeds the overview, working area, and alarm line.
@BOTTOM.PDL: Bottom taskbar providing alarm horn acknowledgment, faceplate recall buttons, and system time.
@OVERVIEW1.PDL: Plant hierarchy display container holding process pictures.

All files prefixed with @ are managed exclusively by the system. They reside in the OS project's graphic directory (<ProjectPath>\<OS_Name>\GraCS\), where they provide the underlying runtime infrastructure.

Why '@' Pictures Are Filtered in SIMATIC Manager

When engineers browse the WinCC OS project within SIMATIC Manager (Component View > OS > Pictures), only user-created process pictures (e.g., Reactor_Area.pdl, Water_Treatment.pdl) are displayed. All @ pictures are intentionally hidden from this view.

Siemens filters these files in SIMATIC Manager to prevent engineers from accidentally deleting or renaming vital system templates. To view and edit @ pictures, an engineer must open WinCC Explorer directly and browse via Graphics Designer or inspect the physical GraCS directory in Windows File Explorer. In Graphics Designer, all @ pictures appear in the file list unless an active view filter (*.pdl without @) is enabled in the filter toolbar.

The Role of the OS Project Editor in Picture Generation

The OS Project Editor is the automated commissioning engine that configures screen resolution, monitor count (single, dual, quad-monitor layouts), message line formatting, and horn integration.

When you run the OS Project Editor:

It reads the target screen resolution (e.g., 1920x1080, 1280x1024) and monitor layout from its settings tab.
It copies template .pdl files from the Siemens system directory (<Siemens_Path>\WinCC\Options\PDL\BaseData\ and Faceplates\) into the local project's GraCS folder, prepending or updating the @ prefix.
It creates and updates internal WinCC system variables (such as @CurrentUser, @ServerNames, @CurrentArea).

Preserving Customizations vs Restoring Factory Defaults

A major hazard occurs when an existing plant has modified @ pictures (for example, embedding a company logo into @TOP.PDL or altering button actions in @BOTTOM.PDL). If an engineer runs the OS Project Editor to fix a missing screen without adjusting the overwrite settings, all customized @ files are overwritten by factory templates.

To safely restore missing pictures without losing customizations:

Perform a Complete Backup of GraCS: Copy the entire GraCS directory to a temporary backup folder prior to launching the editor.
Configure OS Project Editor Overwrite Rules: Open the OS Project Editor. In the Basic Data tab, inspect the list of system pictures. Deselect specific modified pictures or choose 'Do not overwrite' / 'Only update missing files'.
Manual File Extraction: Alternatively, manually extract only the missing @SCREEN.PDL from the Siemens delivery directory and paste it into the project's GraCS folder, avoiding the OS Project Editor entirely.

Standard '@' System Picture Catalog and Functionality

The following table describes critical standard @ pictures and their architectural roles in PCS 7 WinCC:

File NameDisplay LocationPrimary Architectural FunctionRisk Level on Overwrite@SCREEN.PDLRoot Display ContainerHosts top, working, and bottom picture windowsHigh (Resets resolution and monitor layout)@TOP.PDLHeader Bar (Top of Screen)Displays area selection keys, alarm summary, user loginHigh (Overwrites custom logos and header buttons)@BOTTOM.PDLFooter Bar (Bottom of Screen)Displays alarm horn silence, faceplate recall, system timeMedium (Resets button functions to default)@1001.PDLWorking Area ContainerThe picture window into which user process screens loadLow (Pure display container)@ALARMVIEW.PDLBottom Alarm BannerShows the latest incoming unacknowledged high-priority alarmMedium (Resets alarm columns and colors)@PG_*.PDLFloating WindowStandard faceplate templates for APL / CEMAT block typesHigh (Removes custom faceplate modifications)

Verification

Verify system picture availability and layout stability through the following steps:

Open the project in WinCC Explorer. Select Graphics Designer and ensure the filter shows all files (*.* or *.pdl).
Verify that @SCREEN.PDL appears in the list and can be opened in Graphics Designer without file not found errors.
In WinCC Explorer, right-click the OS computer name, select Properties, and check the Graphics Runtime tab.
Confirm that Start Picture is set to @SCREEN.PDL.
Activate WinCC Runtime. Confirm that the top navigation bar, main process area, and bottom alarm line initialize cleanly without grey 'Picture not found' placeholders.

Limitations and Operational Precautions

Consider these operational rules when managing system pictures:

Never Rename @SCREEN.PDL in Start Picture: Renaming the start picture breaks the PCS 7 window manager and picture tree navigation scripts, causing faceplates and alarms to fail.
Multi-Monitor Layout Changes: Changing monitor layout (e.g., from 2 screens to 4 screens) in OS Project Editor requires regenerating @SCREEN.PDL and recompiling the OS; do not attempt to resize @SCREEN.PDL manually in Graphics Designer.
Version Migration Rules: During PCS 7 version upgrades (e.g., V8.0 to V8.2), running the OS Project Editor is mandatory to update internal C-scripts inside @ pictures to match new runtime DLLs.

Engineer FAQ

How do I add a corporate logo to @TOP.PDL permanently?

Edit @TOP.PDL in Graphics Designer, insert the logo, and save it. Then create a backup copy in a safe directory so it can be restored if the OS Project Editor is re-run in the future.