Resolving 'Matrix Stopped Executing - Frozen Value Cycle Count' in SIMATIC Safety Matrix WinCC Faceplates

The error 'Matrix Stopped executing - Frozen value cycle count, Probably F-STOP' appearing in SIMATIC Safety Matrix WinCC faceplates while the CPU is running indicates that WinCC has detected an unvarying cycle counter tag (CYC_CNT) from the Safety Matrix runtime block. If monitoring works inside SIMATIC Manager Component View, the AS safety program is running normally, and the fault is an OS-side tag database discrepancy. To resolve this error, execute an 'Entire OS Compilation with Memory Reset' in SIMATIC Manager to purge stale WinCC tag tables, recreate matrix tag structures, and synchronize the faceplate cycle monitor.

Safety Matrix Faceplate Architecture and Execution Monitoring

SIMATIC Safety Matrix (such as Safety Matrix V6.2 / V6.3 in PCS 7 v8.1 / v8.2) allows engineers and operators to visualize Cause-and-Effect logic running in fail-safe S7-400FH or CPU 410-5H controllers (6ES7410-5HX08-0AB0).

In the AS, the compiled matrix executes as a fail-safe Function Block (F_MA_...) inside the safety runtime group (OB35). In WinCC, the matrix is visualized using the @PG_F_MA_... faceplate. To ensure that operators do not make safety bypass decisions based on obsolete or frozen data, the WinCC faceplate script actively monitors the dynamic health of the safety controller.

Mechanism of the 'Frozen Value Cycle Count' Alarm

The Safety Matrix block increments a dedicated internal cycle counter output (CYC_CNT) on every execution of its fail-safe OB scan.
* Health Polling: When an operator opens the matrix faceplate in WinCC Runtime, an internal C-action continuously reads the CYC_CNT tag via the S7 Named Connection.
* Freeze Detection: If the faceplate observes that CYC_CNT remains completely static across multiple update intervals (typically 3 to 5 seconds), the script infers that the safety task has aborted.
* Visual Warning: The faceplate disables matrix grid interaction, overlays the banner 'Matrix Stopped executing', and displays the tooltip: 'Frozen value cycle count, Probably F-STOP'.

Diagnostic Differentiation - True F-STOP vs WinCC Tag Desynchronization

When this error appears, the engineer must immediately determine whether the safety controller has suffered an actual safety shutdown:

Diagnostic CheckActual F-STOP ConditionWinCC Tag Desynchronization (This Issue)CPU LEDsS7-400H INTF / EXTF illuminated; STOP modeCPU in solid RUN mode; safety program activeComponent View MonitoringCannot go online; safety program haltedOnline monitoring in SIMATIC Manager works perfectlyDiagnostic BufferContains Event 16#F980 "F-STOP asserted"Clean diagnostic buffer; 0 safety fault eventsSafety Matrix Faceplate"Matrix Stopped executing""Matrix Stopped executing"Root CauseActual logic trap, CRC error, or F-I/O faultStale DB offsets in WinCC tag database

Resolution Procedure - Entire OS Compile with Memory Reset

When Component View monitoring proves that the AS is actively executing the matrix, the fault is isolated to corrupted or misaligned WinCC tag mapping. A standard delta compile will not fix this condition.

Execute an Entire OS Compile with Memory Reset:

[SIMATIC Manager -> Component View]
   │
   ├─► Right-click OS Object -> Select: "Compile"
   ├─► In the OS Compilation Wizard:
   │     • Select Target OS and click Next
   │     • Select S7 Programs and click Next
   │
   ├─► In the "Select the network connections and compile data" step:
   │     • Scope: MANDATORY -> Select (•) "Entire OS"
   │     • Checkbox: MANDATORY -> [x] "With memory reset"
   │
   ├─► Click Compile
   └─► Wizard clears WinCC tag management cache and reconstructs all matrix tags

Upon completion, download the OS project to the target OS Server. The newly compiled tag image establishes clean communication with CYC_CNT, clearing the error immediately.

Verification

To confirm that the Safety Matrix faceplate error is resolved:
1. In WinCC Runtime, click on the Safety Matrix block icon to open the main matrix faceplate.
2. Confirm that the banner 'Matrix Stopped executing' and the tooltip 'Frozen value cycle count' have completely disappeared.
3. Verify that the matrix grid displays active dynamic status colors (green for active permissive, red for tripped causes, yellow for bypass).
4. Inspect the dynamic update of cause analog values and digital states within the faceplate; confirm they mirror live field transmitters.
5. In SIMATIC Manager Component View, verify that online monitoring continues to operate in parallel without communication degradation.

Limitations and Operational Precautions

An 'Entire OS Compile with Memory Reset' must be followed by an Entire OS Download to target runtime servers. Performing an entire OS download requires stopping WinCC Runtime on single-station systems or executing a coordinated redundant server failover (downloading standby server first, synchronizing, failing over, and then downloading the primary). Never perform an entire OS download without verifying server redundancy health.

Engineer FAQ

Why did monitoring in SIMATIC Manager work while WinCC reported 'Matrix Stopped'?

SIMATIC Manager reads data directly from the AS safety database using internal engineering protocols. WinCC reads data via the S7 Protocol Suite using tags generated during OS compilation. If an AS compile altered DB numbers without a full OS compile, WinCC reads obsolete memory.

What does 'With memory reset' do during OS compilation?

'With memory reset' instructs the compiler to completely wipe the existing WinCC tag management structures, variables, and cross-references for that AS before compiling fresh data, eliminating orphaned tag addresses.

Can regenerating C-script headers in WinCC fix this error?

Regenerating C-headers resolves script syntax compilation errors, but cannot fix an incorrect tag address pointer coming from the AS.

Does this error affect actual plant safety interlocks in the controller?

No. The Safety Matrix algorithm runs inside the fail-safe S7-400H/410 CPU independently of WinCC. Safety interlocks remain 100% active and protective even if the WinCC faceplate fails to monitor them.