Managing Chart-Based Runtime Groups in SIMATIC PCS 7 V8.2: Resolving Auto-Created Runtime Groups

In SIMATIC PCS 7 V8.2, inserting blocks creates unwanted new runtime groups instead of placing them into existing groups when legacy projects with custom runtime group names conflict with the new 'Chart-based runtime group management' feature. Resolve this by standardizing runtime group names to match the format ChartName[ChartName] using the chart-based migration tool, or setting the project property to non-chart-based management and explicitly marking the predecessor insertion position.

The Paradigm Shift: Chart-Based Runtime Group Management in V8.2

Starting with SIMATIC PCS 7 V8.2 (incorporating CFC V8.2), Siemens introduced a fundamental architectural enhancement to the execution model: Chart-based Runtime Group Management (planbasierte Ablaufgruppenverwaltung).

In previous versions (PCS 7 V8.0, V7.1, and earlier):
* Runtime groups inside CPU organization blocks (OB30 to OB38) were loosely coupled to CFC charts.
* Engineers could manually create runtime groups with arbitrary names (e.g. Pumps_OB35, Fast_Control), distribute blocks from a single chart across multiple runtime groups, or assign custom insertion positions.

In PCS 7 V8.2:
* To optimize multi-user engineering, selective downloads, and automated chart deletion/movement, CFC binds each chart to a dedicated, unified runtime group container named ChartName[ChartName].
* Whenever a block is added to a chart, CFC automatically places the block into the chart's unified group.

However, when engineers migrate or copy-paste legacy projects from PCS 7 V8.0 into V8.2, a persistent glitch arises:
* Inserting any new block into an existing CFC chart—whether from the library or by copying an existing block—ALWAYS creates a brand new, isolated runtime group in the OB, rather than placing the block into the chart's existing runtime group!
* Even explicitly right-clicking a block and selecting Predecessor for Insertion Position (Einbau-Position) fails to prevent the creation of new groups, turning routine chart editing into a frustrating maintenance burden.

Root Cause Analysis: Why Inserting Blocks Creates Spurious Runtime Groups

The creation of unwanted runtime groups stems from naming discrepancies and unmigrated database metadata:

Name Mismatch Between Chart and Legacy Runtime Group:
* Chart-based management relies on exact string correspondence. The runtime group must match the chart name and contain the chart identifier in brackets: ChartName[ChartName].
* In legacy projects, groups were often manually renamed (e.g. Group1, Motor_Logic).
* When a new block is inserted in V8.2, the CFC editor searches the target OB for a group matching ChartName[ChartName]. Failing to find an exact match, the editor concludes that no runtime group exists for this chart and automatically creates a new one!
Copied Charts vs. Migrated Projects:
* Simply copying (Copy & Paste) charts or block folders from a V8.0 project into a V8.2 project bypasses the internal project migration engine.
* As a result, the internal project attribute flag for runtime group management remains in an ambiguous state: the project is flagged for chart-based management, but the individual chart containers retain legacy database pointers.
Renaming Legacy Groups Manually Fails:
* If an engineer manually renames a runtime group to ChartName, CFC does not automatically append the internal system bracket binding [ChartName]. Without this internal relational tag, the compiler continues to treat the group as non-chart-based, perpetuating the auto-creation of new groups.

Step-by-Step Resolution and Migration Procedure

Method 1: Execute Formal Migration to Chart-Based Management (Recommended)

Close all open CFC and SFC chart editors.
In SIMATIC Manager, switch to Component View and select the Charts folder of the target AS.
In the main menu, select Options > CFC > Chart-based Runtime Group Management... (or check project properties).
Run the automated migration wizard:
* The utility scans all charts, aligns runtime groups, renames them to ChartName[ChartName], and consolidates scattered blocks into coherent, chart-aligned containers.
Once migration completes, open any CFC chart and test block insertion.

Method 2: Disabling Chart-Based Management (Reverting to Legacy Behavior)

If plant engineering guidelines require preserving custom, hand-crafted runtime groups:
1. In SIMATIC Manager, select the Charts container.
2. Select menu Options > Customize > CFC....
3. In the CFC Settings dialog, locate the option Chart-based runtime group management.
4. Uncheck this option (or select Non-chart-based runtime group management).
5. Click OK.
6. Open the chart, press Ctrl + F9 to open the Run Sequence editor.
7. Right-click the desired custom runtime group and select Predecessor for Insertion Position (Vorgänger für Einbauposition).
8. New blocks inserted in the chart will now obey the manual insertion pointer without creating new groups.

Method 3: Consolidating Orphaned Runtime Groups Manually

If unwanted groups have already proliferated:
1. Press Ctrl + F9 in the CFC editor to open the Run Sequence window.
2. Expand the affected cyclic interrupt OB (e.g. OB35).
3. Identify the spurious auto-created runtime groups.
4. Drag all blocks from the spurious groups into the primary chart runtime group.
5. Select and delete the empty orphaned runtime groups.
6. Right-click the primary runtime group and select Predecessor for Insertion Position.

Runtime Group Management Modes Comparison

Feature / BehaviorChart-Based Runtime Groups (V8.2 Standard)Non-Chart-Based Runtime Groups (Legacy Mode)Naming ConventionStrictly enforced: ChartName[ChartName]Custom user names permitted (e.g. Pumps_OB35)Block Insertion BehaviorAutomatically placed into the chart's unified groupPlaced at configured 'Predecessor for Insertion Position'Multi-User EngineeringHighly optimized; prevents runtime group conflictsSusceptible to insertion pointer collisionsChart Movement / DeletionDeleting chart automatically purges runtime groupDeleting chart can leave empty orphaned groups in OBMigration RequirementRequires running migration utility on legacy projectsNative behavior for pre-V8.2 projects

Verification

Open an existing CFC chart in the migrated PCS 7 V8.2 project.
Press Ctrl + F9; verify the runtime group in OB35 is formatted as ChartName[ChartName].
Drag a new block (e.g. Add_R or Pcs7AnIn) from the catalog onto the chart canvas.
Press Ctrl + F9; confirm the new block is inserted directly into ChartName[ChartName].
Verify that zero new runtime groups were created in OB35.
Execute Chart > Compile > Changes only; confirm clean compilation with 0 Errors.

Limitations and Operational Precautions

Execution Order Verification: When migrating legacy projects to chart-based runtime groups, verify the execution sequence of interdependent blocks. If a chart contains blocks that were intentionally split across OB35 and OB32, ensure the migration preserves necessary multi-OB task assignments.
Avoid Copy-Pasting Across Major Versions: Avoid copying raw chart folders across differing PCS 7 major versions over Windows Explorer. Always utilize official project retrieval (File > Retrieve...) and execute formal library update wizards.
Run Sequence Optimization: After consolidating runtime groups, execute Options > Optimize Run Sequence in CFC to ensure blocks are sorted logically by signal flow, eliminating unnecessary dead-time delays.

Engineer FAQ

Why did Siemens introduce Chart-based Runtime Group Management in V8.2?

To eliminate the administrative overhead of manually organizing runtime groups and to support enhanced multi-user engineering, selective chart compilation, and advanced project comparisons in Version Cross Manager (VXM).

Can a single chart still have blocks executing in different OBs under chart-based management?

Yes. If blocks within a single chart are assigned to different OBs (e.g. OB32 and OB35), CFC creates two chart-based groups: ChartName[ChartName]_OB32 and ChartName[ChartName]_OB35.

What does the bracket notation Chart(1)[Chart(1)] mean?

The text outside the bracket is the runtime group name, and the text inside the brackets is the linked parent CFC chart name. This bracketed link enables automated lifecycle synchronization.