Restricting Alarm Visibility, Message Lists, and Acoustic Horns by Plant Area in SIMATIC PCS 7

In SIMATIC PCS 7 V8.1, restricting alarm visibility and acoustic horns between user groups (e.g. Plant 1 vs. Plant 2) is achieved by assigning technological objects to distinct Plant Hierarchy Areas and configuring User Administrator monitoring authorizations. When an operator lacks monitoring rights for an area, WinCC Alarm Control automatically filters out those messages and suppresses associated acoustic horn triggers.

Operational Objectives and Alarm Segregation Principles

In multi-unit industrial facilities running SIMATIC PCS 7 V8.1 (such as combined utilities, chemical batch areas, or multi-train paper plants), control room operator consoles frequently serve different operational teams:
* User Group 1 (Plant 1 Operators): Must supervise and acknowledge alarms originating strictly from Plant Area 1.
* User Group 2 (Plant 2 Operators): Must supervise and acknowledge alarms originating strictly from Plant Area 2.

Plant management requires that when an operator logs in:
1. The WinCC Alarm Control message banner and alarm hit lists display messages solely for their authorized plant section.
2. The Acoustic Signaling Device (Horn) sounds only when an alarm occurs within their authorized plant area, eliminating unnecessary acoustic distraction caused by adjacent processes.
3. Higher-level area summary buttons in the overview area bar display alarm indications only for authorized areas.

In SIMATIC PCS 7, this segregation does not require custom C-scripts or SQL filter modifications; it is handled natively by the integration between the Plant Hierarchy, WinCC User Administrator, and WinCC Horn.

Plant Hierarchy Areas and User Administrator Authorization

The alarm filtering mechanism operates through three interconnected architectural layers:

Plant Hierarchy (PH) Area Allocation:
* In SIMATIC Manager Plant View, technological hierarchy folders are configured as Areas (e.g., folder Plant_1 has property Area = Plant_1).
* All CFC charts, technological blocks (e.g. MotL, MonAnL), and process graphics created inside that folder inherit the parent area identity.
* During Compile OS, the area names are automatically synchronized into the WinCC database and embedded into every message record as the internal message attribute Area.
WinCC User Administrator Authorization Levels:
* The OS compiler automatically creates area-specific authorization levels in WinCC User Administrator:
- Area Authorization 1000 (Plant_1 - Monitoring)
- Area Authorization 1001 (Plant_1 - Process Controlling)
- Area Authorization 1002 (Plant_1 - Higher Process Controlling)
- Area Authorization 1010 (Plant_2 - Monitoring)
- The basic permission Monitoring (Area - Monitoring) determines whether an operator can view pictures and receive alarms for that area.
Native Alarm List Filtering and Acoustic Horn Suppression:
* WinCC Alarm Control evaluates the Windows user token currently logged into the OS client. If the user lacks the Area - Monitoring permission for Plant_2, the alarm control automatically applies an internal filter suppressing all messages where Area = 'Plant_2'.
* WinCC Horn Integration: The WinCC Horn service processes incoming alarms to trigger sound cards or digital outputs. Horn triggers evaluate the active user's area permissions; alarms from unmonitored areas are suppressed and do not activate the horn.

Step-by-Step Configuration Workflow for Area Segregation

1. Verify Area Definitions in the Plant Hierarchy

In SIMATIC Manager, switch to Plant View.
Right-click the top-level folder for Unit 1, select Object Properties.
Under the Plant Hierarchy tab, confirm the folder is marked as an Area (e.g., named Plant_1).
Repeat for Unit 2 (e.g., named Plant_2).
Ensure all CFC charts and process pictures reside within their respective unit folders.

2. Execute OS Compilation to Synchronize Area Security Keys

In SIMATIC Manager Component View, select the OS station.
Select PLC > Compile and Download Objects.
Run OS compilation with scope Entire project (or changes).
This exports the area names into the WinCC project database.

3. Configure User Groups in WinCC User Administrator

Open the WinCC project on the OS Server in WinCC Explorer.
Double-click User Administrator.
Create user groups: Group_Plant_1 and Group_Plant_2.
In the Authorization Matrix for Group_Plant_1:
* Grant authorization 1000: Plant_1 - Monitoring.
* Grant authorization 1001: Plant_1 - Process Controlling.
* Deselect / Remove all monitoring and controlling permissions for Plant_2.
In the Authorization Matrix for Group_Plant_2:
* Grant authorizations for Plant_2.
* Deselect all authorizations for Plant_1.
Assign individual operator accounts to their respective groups.

4. Configure WinCC Horn Message Assignment

In WinCC Explorer, double-click Horn.
Select the Message assignment tab.
Configure message classes (e.g. Alarm, Warning, Tolerance) to target output signals (e.g. Horn_WAV_Sound1).
In the Authorization check settings, ensure Check operator authorization is enabled.
Save settings and close Horn configuration.

Area Authorization and Alarm Behavior Matrix

Logged-In UserArea Authorization ConfiguredWinCC Alarm Control DisplayAcoustic Horn BehaviorArea Overview Bar StatusOperator Plant 1Plant_1 (Monitoring = YES) / Plant_2 (NO)Displays alarms from Plant_1 onlySounds only for Plant_1 alarmsFlashes only on Plant_1 area buttonOperator Plant 2Plant_1 (NO) / Plant_2 (Monitoring = YES)Displays alarms from Plant_2 onlySounds only for Plant_2 alarmsFlashes only on Plant_2 area buttonShift SupervisorPlant_1 (YES) and Plant_2 (YES)Displays combined alarms across all unitsSounds for alarms from both unitsFlashes on all affected area buttonsNo User Logged InDefault guest permissions (Monitoring = NO)Displays empty message list or public viewHorn suppressed completelyDisplays public overview without alarms

Verification

In WinCC Runtime, log in as Operator_Plant_1.
Generate a test process alarm in Plant_2 (e.g. simulate high level on tank TK_201).
Verify that the alarm does NOT appear in the incoming alarm list on the Operator_Plant_1 station.
Confirm that the acoustic horn does NOT sound on the Operator_Plant_1 station.
Log in as Operator_Plant_2 on the adjacent console; verify the alarm appears immediately in the alarm list and triggers the horn.
Acknowledge the alarm on the Plant_2 console; verify the acoustic horn silences immediately.

Limitations and Operational Precautions

Shared Common Utilities: Equipment shared between plants (such as a shared emergency firewater pump or common flare header) must be assigned to a dedicated common area (e.g. Common_Utilities), and both operator groups must be granted monitoring rights to that area.
Never Modify SQL Alarm Filters Manually: Do not attempt to write custom SQL scripts to filter alarms by user in the underlying @AlarmView PDLs; standard PCS 7 updates will overwrite manual script alterations.
Server Package Synchronization: In distributed multi-client architectures, user administrator settings must be maintained consistently across redundant servers or managed centrally via SIMATIC Logon.

Engineer FAQ

Can an operator see process pictures of an area if they cannot see its alarms?

No. In standard PCS 7, the permission Area - Monitoring controls both picture navigation and alarm visibility. Revoking monitoring rights hides both process pictures and alarms.

How do I silence the acoustic horn without acknowledging alarms?

PCS 7 provides a dedicated Horn Acknowledge button in the top navigation area bar. Clicking it silences the sound immediately while leaving the alarms in the unacknowledged state.

Can I manage operator group authorizations using Windows Active Directory?

Yes. By installing SIMATIC Logon, WinCC User Administrator groups can be mapped directly to Windows Domain Active Directory user groups, centralizing user management.