Limiting Faceplate Instances to a Single Active Window in SIMATIC PCS 7 WinCC

To restrict open faceplates so that only a single instance of any given technological block faceplate can be open simultaneously in SIMATIC PCS 7 WinCC, configure the faceplate runtime settings in the OS Project Editor. In WinCC Explorer, open the OS Project Editor, navigate to the 'Runtime window' tab, and check the option 'Open faceplate once' (or set 'Maximum number of identical faceplates' to 1). When this option is active, clicking an already-opened block icon brings the existing faceplate window directly to the foreground and sets focus, completely preventing duplicate window clutter across operator screens.

Executive Summary

In high-density industrial control rooms, operator workstation ergonomics depend heavily on structured window management. By default, standard SIMATIC PCS 7 WinCC configurations allow operators to open multiple instances of the same faceplate (e.g., repeatedly clicking a pump icon opens multiple overlapping pump faceplates up to the configured window ceiling). This behavior clutters screens, obscures critical process overviews, and can lead to operational confusion during alarms. Automation engineers frequently seek an elegant mechanism to enforce a strict single-instance policy: clicking a technological object must open its faceplate, but subsequent clicks on that same object should merely bring the open faceplate to the foreground rather than spawning duplicates. This setting is managed centrally through the WinCC OS Project Editor.

WinCC Faceplate Management Architecture: Multiple vs Unique Instances

When an operator clicks a block icon in WinCC Runtime, the script PCS7_OpenGroupDisplay_V6 or APL_OpenFaceplate queries the WinCC picture window management cache:

Unrestricted Multi-Instance Mode: Each click allocates a new picture window container (@Faceplate_1, @Faceplate_2, etc.) until the global maximum faceplate limit (e.g. 16 windows) is reached.
Single-Instance Enforcement Mode: WinCC maintains an internal lookup table of active tag prefixes (@ServerName::Plant/Unit/Motor). If a window container is already bound to the requested tag prefix, WinCC suppresses window instantiation and brings the existing window to the top of the z-order.

The OS Project Editor Window Management Framework

The OS Project Editor generates the fundamental system picture hierarchy (@screen.pdl, @overview1.pdl, @alarmline.pdl). Within its configuration interface:

Maximum number of faceplates: Sets the total ceiling of concurrent open faceplates across all technological blocks (e.g. 8 or 12).
Maximum number of identical faceplates / Open faceplate once: Controls whether multiple instances of the exact same technological block can exist concurrently.

Functional Mechanics of 'Open Faceplate Once'

Enabling Open faceplate once modifies the internal window allocation script in @screen.pdl. When a call arrives:

WinCC evaluates the tag prefix of the clicked icon.
It scans active picture windows (@Faceplate*).
If an active window matches the tag prefix, it sets property Visible = TRUE and invokes Windows API SetForegroundWindow.
If no match is found, it instantiates a new window in the next available slot.

Faceplate Window Management Strategy Comparison

The following table compares window management settings in the WinCC OS Project Editor:

Configuration ParameterSetting OptionOperational BehaviorOperator Ergonomics ImpactOpen faceplate onceChecked (Enabled)Exactly 1 window allowed per block; brings existing window to front.Clean screen; zero duplicate window clutter (Recommended).Open faceplate onceUnchecked (Disabled)Spawns multiple windows for the same block on repeated clicks.Cluttered desktop; overlapping duplicate windows.Max Number of FaceplatesRange 1 to 16Absolute limit of total concurrent faceplates open across plant.Prevents memory exhaustion on operator IPCs.Positioning ModeCentered / CascadeDetermines screen coordinates where new faceplates appear.Cascading provides clear multi-loop viewing.Close on Picture ChangeEnabled / DisabledDetermines whether faceplates close when navigating to a new area.Keeping open allows cross-area process monitoring.

Step-by-Step Configuration Procedure in OS Project Editor

Method 1: Enabling Single-Instance Faceplates in WinCC Explorer

Open the OS project in WinCC Explorer.
In the navigation pane, double-click OS Project Editor.
Select the Runtime window tab.
In the faceplate management section, locate the option labeled Open faceplate once (or Maximum number of identical faceplates).
Check the box Open faceplate once (or set the maximum identical value to 1).
Verify the Maximum number of faceplates is configured to a sensible limit (e.g. 8 or 12).
Click OK to re-generate the system window management scripts.
Activate WinCC Runtime to test the new window behavior.

Verification

To verify single-instance faceplate behavior:

Initial Click Check: In WinCC Runtime, click on a motor block icon (MotL). Confirm that the motor faceplate opens.
Duplicate Click Check: Without closing the open faceplate, click the exact same motor icon a second time. Confirm that NO secondary faceplate opens and that the existing faceplate remains in focus.
Different Block Check: Click a neighboring valve block icon (VlvL). Confirm that the valve faceplate opens alongside the motor faceplate smoothly.

Limitations and Operational Precautions

OS Project Editor System Regeneration: Running the OS Project Editor regenerates standard system pictures (@screen.pdl). Ensure that custom modifications were made in configured typical files rather than directly in @screen.pdl.
Multi-Monitor Workstations: On multi-monitor operator stations, the single-instance rule applies across all monitors; clicking an icon on Monitor 2 will bring the faceplate open on Monitor 1 to the front.
Server-Client Replication: For multi-client architectures, execute the OS Project Editor on the master Base OS Client and download changes to all clients.

Engineer FAQ

Can I allow two instances of a faceplate for side-by-side comparison while preventing infinite duplicates?

Yes, in OS Project Editor you can set 'Maximum number of identical faceplates' to 2, permitting side-by-side comparison while capping instances.

Does this setting apply to custom user-designed popups?

It applies to all pictures opened via standard PCS 7 faceplate calling scripts (PCS7_OpenGroupDisplay / APL_OpenFaceplate); custom C-script popups require custom window management.

Will running OS Project Editor reset my WinCC screen resolution?

It retains the selected resolution as long as you do not change the resolution radio button on the Layout tab.

Technical References

Related Tags

https://industrialautomation.net/search?query=simatic-pcs7
https://industrialautomation.net/search?query=wincc-scada
https://industrialautomation.net/search?query=os-project-editor
https://industrialautomation.net/search?query=faceplates

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Limiting Faceplate Instances to a Single Active Window in SIMATIC PCS 7 WinCC