Resolving OS Compile Warning 'Chart Folder of S7 Program Has Not Been Compiled' in PCS 7

In SIMATIC PCS 7 V9.0, receiving the OS compilation warning 'The chart folder of S7 program AS01\AS01_Prog has not been compiled' indicates that the WinCC OS compiler was executed before the Continuous Function Charts (CFC) in the controller were compiled into executable machine code. The OS compilation wizard scans the S7 program database to extract technological tags, message definitions, and operator faceplate linkages. If the CFC chart folder has not been compiled, or if changes remain uncommitted, the database contains stale or missing block instances, leaving the OS tag dictionary incomplete. To resolve this, compile the CFC charts with module drivers generated, verify Plant Hierarchy assignments, and recompile the OS.

PCS 7 OS Compilation Architecture and Data Exchange

The core engineering strength of SIMATIC PCS 7 is its unified engineering database. Unlike traditional SCADA systems where PLC tags and HMI addresses are configured independently, PCS 7 employs the OS Compiler to automatically transfer technological information from the automation controller (AS) to the operator station (WinCC OS).

When an engineer designs control logic in Continuous Function Charts (CFC), technological function blocks (such as MotL, VlvL, or PIDConL) contain parameters marked with the system attribute S7_m_c := 'true'. When CFC compilation is executed (Chart -> Compile -> Changes Only / Entire Program), the CFC compiler translates the graphical charts into S7 machine blocks (FBs, FCs, and DBs) and builds an internal relational cross-reference database in the project's S7 program folder.

During OS Compilation, WinCC queries this S7 program database, creates WinCC internal and external tags, configures Alarm Logging message servers, and populates Picture Tree hierarchy nodes. If the OS compiler detects that the CFC charts have never been compiled or that chart edits have made the database out of date, it halts tag generation for that station and logs: 'Warning: The chart folder of S7 program ... has not been compiled'.

Root Causes of Uncompiled Chart Folder Warnings

Technical evaluation reveals three primary project conditions that trigger this OS compilation warning:

Execution Sequence Inversion: In newly created projects or after restoring archived multiprojects, engineers frequently run the Compile OS wizard without first compiling the S7 program. The OS compiler detects an empty or uninitialized block container and issues the warning.
Unassigned or Misaligned Plant Hierarchy: The OS compiler relies on the Plant Hierarchy (TH) to map charts to OS pictures and areas. If the Plant Hierarchy folder properties have not been formally assigned to an S7 program and a target OS, the compiler fails to establish the technological link to the chart folder.
CFC Compilation Errors in Delta State: If an engineer previously initiated a CFC compilation that terminated with errors (e.g., missing block types, unaddressed module drivers, or syntax faults), the compiler leaves the chart folder in an 'uncompiled / invalid' state flag. Even if the charts appear intact in the editor, the database flag suppresses OS compilation.

CFC and OS Compilation Sequence and Diagnostic States

The following table summarizes compiler states, data dependencies, and corrective actions in PCS 7:

Compiler StepPrerequisiteOutput ArtifactSymptom if Step SkippedHW Config CompileHardware addresses assignedSystem Data Blocks (SDBs)Driver generator fails to link I/O addressesCFC Chart CompileHW Config compiled cleanlyMachine code DBs & Tag DBOS Compiler logs 'Chart folder not compiled'Module Driver Gen'Generate module drivers' checked@... driver blocks in CFCQuality codes report bad/fault on OSOS CompilationCFC chart compiled cleanlyWinCC Tags, Alarms, ArchivesMissing tags, greyed-out faceplatesBlock Icon WizardOS compiled cleanlyProcess picture block iconsMissing or unlinked block icons

Step-by-Step Procedure to Resolve OS Compile Warnings

To resolve the warning and establish a clean, error-free OS compilation:

Compile the Hardware Configuration:
- In SIMATIC Manager, open HW Config for the target AS controller.
- Select Station -> Save and Compile.
- Ensure that hardware compilation completes with zero errors.
Compile the CFC Chart Folder:
- In SIMATIC Manager, browse to the target CPU's S7 Program -> Charts folder.
- Double-click any CFC chart to launch the CFC editor.
- Select Chart -> Compile -> Entire Program (or Changes Only if compiling subsequent modifications).
- In the compile options dialog, ensure the checkbox Generate module drivers is checked.
- Click OK and verify that compilation finishes with 0 Errors and acceptable warnings.
Verify Plant Hierarchy Assignment:
- Switch to Plant View in SIMATIC Manager.
- Right-click the top-level plant folder and select Object Properties.
- Select the AS-OS Assignment tab.
- Ensure that the assigned S7 Program matches your controller (e.g., AS01\AS01_Prog) and the assigned OS matches your operator station project.
Recompile the Operator Station (OS):
- In Component View, right-click the OS project and select Compile.
- In the OS Compile wizard, select your target S7 program and check Tags and messages and SFC Visualization.
- Select Entire project (or Changes Only) and click Compile.
- Confirm that the compilation log finishes with: 'The compilation was completed with 0 errors, 0 warnings'.

Verification

Verify OS tag and communication integrity:
1. Open the OS project in WinCC Explorer.
2. Open Tag Management; expand the SIMATIC S7 Protocol Suite and verify that tag groups for the AS program (e.g., AS01) are populated with technological tags.
3. Open Alarm Logging; verify that messages for all CFC blocks are populated with appropriate alarm texts and message classes.
4. Start WinCC Runtime and confirm that block icons display live controller values without yellow warning triangles or disconnect flags.

Limitations and Operational Precautions

Sequential Dependency: Never attempt to compile an OS project while a CFC chart compilation is in progress, as database locking will corrupt cross-references.
Delta OS Compilation Restrictions: Changes to block types, structure tags, or message attributes require an 'Entire OS' compilation and cannot be updated via delta compile.
Multi-AS Coordination: If an OS project communicates with multiple S7 controllers, ensure that all assigned AS chart folders are compiled before launching OS compilation.

Engineer FAQ

Why does the OS compiler require CFC compilation first?

The OS compiler extracts tags, alarm texts, and attributes from the compiled S7 database. Without CFC compilation, the database does not contain current block structures.

Can I ignore this warning if I only made changes to WinCC graphics?

If you only edited WinCC graphics, OS compilation was not required. However, if OS compilation was run, ignoring this warning means controller changes were not transferred.

What happens if I compile the OS while the CFC chart has compilation errors?

The OS compiler skips the faulted charts, resulting in missing tags, unlinked faceplates, and dead process values in WinCC Runtime.

Does compiling CFC Entire Program stop the CPU?

Compiling the entire program does not affect the running CPU. However, downloading the entire program requires placing the CPU in STOP mode. Delta downloads can be performed in RUN.