Resolving Missing Tag Values in SIMATIC Information Server Reports with Process Historian V8.1

In SIMATIC PCS 7 systems pairing redundant OS servers with a standalone Process Historian (PH) and Information Server (IS) V8.1, when IS web reports display 'No record found' for historical analog tags despite the PH dashboard showing active tag logging throughput (e.g. 6 values/sec) and alarm reports functioning normally, the root cause is corrupted or desynchronized OS archive metadata catalogs in the Process Historian database. Resolving this issue requires resetting the historical archive link, performing an 'Entire OS Compile with Memory Reset' on the Engineering Station, downloading the complete OS project to the runtime servers, and re-registering the OS archive packages in the Information Server administration portal.

Process Historian and Information Server Data Flow Architecture

In SIMATIC PCS 7 enterprise reporting architectures:
1. WinCC OS Servers:
- Collect real-time process values and store short-term segments in ArchiveManager\TagLoggingFast and TagLoggingSlow.
- The Process Historian Ready (PH-Ready) service running on each OS Server streams completed database segments across the terminal bus to the central historian.
2. SIMATIC Process Historian (PH):
- Aggregates long-term plant data in a high-capacity Microsoft SQL Server enterprise database.
- Maintains separate storage tables for Alarm History and Tag Logging Time-Series Data.
3. SIMATIC Information Server (IS):
- A web-based reporting framework (Microsoft SQL Server Reporting Services / IIS).
- Queries the PH database via authenticated web service calls to generate scheduled PDF, Excel, and Word reports.
- Relies on internal metadata catalogs that map human-readable tag names (e.g. TIC_101.PV_Out#Value) to internal SQL variable IDs (VariableID).

Why Historical Alarms Work While Analog Tag Reports Display 'No Record Found'

The discrepancy where alarm reports succeed but tag reports fail stems from fundamentally different storage schemas:
- Alarm Data Independence:
* Alarm records carry complete self-contained text payloads (Date, Time, Message Number, Event Text, Area). Information Server queries alarm tables directly using simple date-range SQL filters.
- Tag Logging Metadata Dependency:
* Analog tag archiving utilizes relational variable mappings. When an engineer selects a tag in the IS web interface, IS interrogates the metadata catalog to resolve the tag's unique GUID and ArchiveID.
* If an OS project underwent incomplete delta compilations or server re-installations, the VariableID in the WinCC OS Tag Logging catalog diverges from the VariableID registered in the Process Historian database.
* Although PH actively logs raw binary value blocks (showing 6 values/s on the dashboard), Information Server's query fails to correlate the tag string with the stored time-series points, returning:
text No record found.

Step-by-Step Restoration and OS Metadata Resynchronization

Follow this procedure to re-establish complete metadata alignment between OS Servers, Process Historian, and Information Server:

Purge Corrupted Database Catalogs in Process Historian:
- On the Process Historian server, open Process Historian Management Console.
- Stop the PH service.
- If the historian database has corrupted schema tables, perform an official database reset using the Siemens PH_ResetDatabase.exe utility (or restore from a clean baseline backup).
- Restart the Process Historian service; verify status displays Active / Ready.
Execute Complete OS Compilation with Memory Reset:
- In SIMATIC Manager on the Engineering Station:
- Right-click the OS project and select Compile.
- In the wizard, select Entire OS.
- Check the box With memory reset.
- This wipes all orphaned tag IDs, re-indexes every Tag Logging variable, and creates a synchronized metadata catalog.
Download Complete Project to OS Servers:
- Download the entire project to the redundant OS Servers (OS_Server1 and OS_Server2).
- Launch WinCC Runtime.
- The PH-Ready service automatically detects the new project GUID, transmits the updated metadata catalog to the Process Historian, and begins streaming historical data.
Synchronize Information Server Web Application:
- Open Internet Explorer and navigate to the Information Server administration portal: http://localhost/InformationServer_Admin.
- Under Projects / Data Sources, select the OS project and click Update Metadata (or Re-register Data Source).
- Wait for the synchronization bar to complete: Metadata update successful.
- Open the Reports > Tables / Trends template, select the analog tag, and execute a preview query.

PH and IS Diagnostic Status and Troubleshooting Table

The following table details diagnostic checks across Process Historian and Information Server:

Diagnostic IndicatorObserved BehaviorRoot CauseCorrective ActionPH DashboardShows 'Active' (e.g. 6 values/s)OS is streaming data to PH successfullyIngestion healthy; issue isolated to IS query layerIS Tag Report'No record found' for valid time windowTag metadata GUID mismatch between OS and PHRecompile OS with Memory Reset; re-sync IS metadataIS Alarm ReportReports generate successfullyAlarm tables do not rely on variable ID mappingConfirms SQL connectivity and reporting engine are intactPH-Ready ServiceStatus 'Disconnected' on OS ServerFirewalls blocking port 1433 or SIMATIC Shell issueCheck terminal bus NIC binding and Windows firewallIS Web Client'Data Source Not Available'Information Server application pool stopped in IISRestart IIS service (iisreset) and verify SQL reporting

Verification

To confirm that Information Server is generating tag trend and table reports:
1. Open the SIMATIC Information Server web client in Internet Explorer.
2. Navigate to Templates > Process Values > Table / Trend Report.
3. Select an analog process tag (e.g. TIC_101/PV_Out.Value).
4. Select a time interval encompassing the last 2 hours.
5. Click Preview:
- Confirm that the report renders with a populated data table listing timestamps and engineering values.
- Confirm that the trend graph renders continuous analog curves without gaps.
6. Schedule an automated daily PDF export and confirm receipt in the designated target directory.

Limitations and Operational Precautions

When managing Process Historian databases:
1. Never Manually Truncate SQL Tables: Do not execute raw SQL DROP TABLE or DELETE commands directly in SQL Server Management Studio against PH databases. Use only official Siemens PH administration utilities.
2. Version Compatibility: Ensure that the Information Server version (e.g. V8.1) precisely matches the Process Historian version. Running mixed service pack levels between PH and IS breaks web query WebMethods.
3. Archive Storage Sizing: Ensure the dedicated hard disk volume hosting Process Historian archive segments has at least 20% free space. If disk space drops below 10%, PH will stop accepting incoming OS tags to prevent database corruption.

Engineer FAQ

Why did alarm reports work when tag reports failed in Information Server?

Alarms store plain text attributes directly in the event record, allowing direct retrieval by date. Process tags rely on relational variable ID lookup tables; if the OS and PH metadata catalogs desynchronize, tag lookup fails.

What does 'Entire Compile with memory reset' do to WinCC Tag Logging?

It purges the existing internal tag database pointers in WinCC, re-indexes all variables from source CFC charts, and re-establishes a clean baseline for historian synchronization.

Can Information Server run on the same PC as Process Historian?

Yes. In small to medium architectures, Information Server and Process Historian can be co-installed on a single high-performance server PC. In large plants, dedicated separate servers are recommended.

Where can I verify that tags are actively entering the Process Historian database?

In the Process Historian Management Console dashboard, view the 'Incoming Process Values' counter, or inspect performance counters under Windows Performance Monitor (Process Historian\Values Written/sec).