Safely Deleting Operator Station (OS) Objects from a SIMATIC PCS 7 Multiproject - Reorganizing the Project Database

When splitting a plant or modernizing legacy hardware (such as separating a PCS 7 V7 system into two autonomous facilities where an older section is decommissioned and modern units are migrated to V9.0), removing obsolete Operator Station (OS) objects from the Multiproject requires more than simply deleting the PC station in SIMATIC Manager. An OS object maintains extensive cross-references across NetPro S7 connections, Server Package distribution tables in multi-clients, and AS-OS compiler transfer registries. To remove an OS cleanly without corrupting the Multiproject: first detach server packages from all client stations, delete S7 connections in NetPro, delete the OS object in SIMATIC Manager Component View, and critically execute File -> Save As... with With Reorganization (Slow) to purge orphaned database pointers and defragment project indices.

Architectural Dependencies of OS Objects in a Multiproject

In SIMATIC PCS 7, an Operator Station (OS) is not a standalone graphic drawing; it is an integrated engineering entity. When an OS is created, the engineering database registers the station across multiple interdependent subsystems:

NetPro Connection Table: S7 Named Connections are established between the OS application and every Automation System (AS) controller in the plant.
Server Package Hierarchy: If the OS is a Server, it generates server data packages (.pck) that are imported by OS Clients to resolve picture paths, tag prefixes, and alarm archives.
AS-OS Engineering Database: The central Sybase/SQL engineering database binds CFC block instance messages (MsgEvId) to the specific OS project container.

If an engineer abruptly deletes an OS object from SIMATIC Manager without unlinking these dependencies, orphaned pointers remain embedded in the database, causing future OS compilations to crash or report non-existent partner stations.

Systematic Deletion Workflow: Clients, NetPro, and the OS Object

To decommission and remove an OS object cleanly from a Multiproject, follow this step-by-step procedure:

Decommissioning PhaseAction in SIMATIC Manager / NetProPurposePhase 1: Multi-Client UnlinkingOpen OS Clients; select Server Data; unload/delete package from retired OSPrevents clients from attempting to resolve offline server archivesPhase 2: NetPro Connection PurgeIn NetPro, select the retired OS PC station; delete all S7 connections; recompileClears AS communication buffers and connection table entriesPhase 3: Hardware Config DeletionDelete the SIMATIC PC Station object in SIMATIC Manager Component ViewRemoves the station container and WinCC project directoryPhase 4: Database ReorganizationExecute File -> Save As... with With Reorganization (Slow)Mandatory: Rebuilds relational tables and purges orphaned keys

After Phase 2, compile and download NetPro changes to the physical S7-400 CPUs during a maintenance window so the controllers cease broadcasting diagnostic keep-alive packets to the retired station.

The Mandatory Role of 'Save As with Reorganization (Slow)'

When objects (charts, blocks, or PC stations) are deleted in SIMATIC Manager, the underlying database does not physically erase records; it simply marks them with a deletion tombstone. Over years of plant modifications, deleted objects accumulate, creating index fragmentation and ghost database locks.

Executing File -> Save As... with With Reorganization (Slow) performs a complete, deep-level database defragmentation:

It reads every active record sequentially, skipping tombstoned and deleted items.
It rebuilds the entire relational structure into a clean, newly created project folder.
It recalculates internal cross-reference IDs, eliminating phantom server references and preventing compile crashes.

Depending on project size, reorganization may take between 5 and 30 minutes, but it is an absolute engineering necessity before promoting a modified project to production.

Verification

Verify that the OS object was cleanly purged without lingering cross-reference corruption:

NetPro Consistency Check: Open NetPro. Select Network -> Check Consistency. Confirm that the network topology and remaining connection tables compile with 0 Errors and 0 Warnings.
OS Client Server Data Audit: Open any remaining OS Client in WinCC Explorer. Open Server Data. Verify that the package for the deleted OS no longer appears in the list.
AS-OS Compilation Validation: On the Engineering Station, execute an OS Compile -> Changes Only for the remaining active OS servers. Confirm that compilation completes successfully without searching for the deleted station.

Limitations and Operational Precautions

When removing OS stations from a multiproject, observe these operational safeguards:

Backup Prior to Deletion: Always create a compressed Multiproject ZIP archive (File -> Archive) before deleting any station object.
Physical Hard Drive Purging: Deleting an OS object in SIMATIC Manager deletes the database entry, but depending on configuration, the physical WinCC folder on disk may remain. Inspect the project directory and delete any orphaned WinCC project directories manually.
Redundant Server Pairs: If deleting one node of a redundant OS pair, the remaining partner server must be converted to a Single Station in WinCC Redundancy properties before compiling.

Engineer FAQ

What is the difference between normal 'Save As' and 'Save As with Reorganization (Slow)'?

Normal 'Save As' executes a simple file-copy of the project folder, preserving all fragmented space and deleted records. 'Save As with Reorganization (Slow)' analyzes every record, purges all deleted objects, and rebuilds database indices from scratch.

Will deleting an OS object delete the CFC charts in the AS?

No. The Automation System (AS) and Operator Station (OS) reside in separate project folders within the Multiproject. Deleting an OS has zero impact on CFC charts, block logic, or hardware configurations.

Why does NetPro still show connections to a deleted OS?

If NetPro was not saved and compiled after deleting the PC station, connection routing tables retain the old endpoints. Always open NetPro and execute Save and Compile after station modifications.