C135 PCS 7 (PCS7)
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6 Cielo Ciencia y Tecnología
·Publicada en C135 PCS 7 (PCS7)

Restoring Stalled Historical Tag and Alarm Updates in SIMATIC Information Server

Restoring Stalled Historical Tag and Alarm Updates in SIMATIC Information Server

In SIMATIC Information Server (IS), when reports and dashboards stop updating historical process values and alarms following a server network fault or reboot—even though the plant and WinCC/Process Historian operate normally—the issue is caused by stale connection handles in the Information Server data access layer or a stopped 'Process Historian Ready' (PH-Ready) service. To resolve this, open Windows Services on the Information Server host, restart the 'Information Server Service' and 'PH-Ready Service', verify that the Process Historian data source indicates 'Connected' in the IS web administration portal, and clear cached SSRS session pools.

Table of Contents

Executive Summary

SIMATIC Information Server (IS) provides critical regulatory reporting, batch documentation, and energy management reports by querying historical archives from SIMATIC Process Historian (PH) or WinCC OS Servers. Following a network disruption, server maintenance, or unexpected reboot of the archive host, engineers frequently encounter an operational blind spot: while WinCC runtime displays live alarms and Process Historian logs data normally, Information Server stops updating.

Reports generated in Information Server display flatlined curves, outdated alarm counts, or blank tables ending at the exact timestamp of the network interruption. Because the web portal remains accessible and displays no overt error messages, determining why data stopped flowing is challenging. This condition occurs because the Information Server background polling service and SQL Server Reporting Services (SSRS) connection pools lose their TCP/DCOM session state and fail to re-authenticate against Process Historian automatically. This guide details the diagnostics and service recovery procedures required to restore real-time reporting.

Architecture and Fundamental Mechanics

The communication architecture between Information Server and Process Historian operates through decoupled data pipelines:

  1. The Process Historian Ready (PH-Ready) Component:
    - Both Information Server and WinCC OS nodes install the 'PH-Ready' software agent.
    - PH-Ready establishes an authenticated, encrypted communication channel with the Process Historian server via TCP port 4840 (OPC UA) and SQL port 1433.
    - It buffers queries and synchronizes metadata (such as tag names, archive structures, and plant hierarchy areas).

  2. The Disconnect Stalling Phenomenon:
    - When the Process Historian server (CS1075SR01) restarts or drops network packets:

    • The SQL Server Reporting Services connection pool on Information Server (CS1075SR02) enters an orphaned state.
    • Subsequent report queries receive socket timeout errors that are suppressed in the web front-end, resulting in empty or stale datasets.
    • The background synchronization service on Information Server fails to detect that PH has recovered and does not initiate a re-login handshake without a service cycle.

  3. Administrative Data Source Health Verification:
    - Information Server maintains an internal data source status table in its web administration portal.
    - If the data source state is 'Disconnected', 'Authentication Error', or 'Connecting', report generation engines cannot fetch new archive segments.

Step-by-Step Implementation Procedure

Follow these steps to restore historical data updates in SIMATIC Information Server:

  1. Verify Physical Network and Port Accessibility:
    - On the Information Server PC (CS1075SR02), open Command Prompt.
    - Ping the Process Historian server (CS1075SR01):
    ping CS1075SR01
    - Verify TCP port connectivity using PowerShell:
    Test-NetConnection -ComputerName CS1075SR01 -Port 1433 (SQL Server)
    Test-NetConnection -ComputerName CS1075SR01 -Port 4840 (OPC UA)
    - Confirm that both ports report TcpTestSucceeded : True.

  2. Inspect and Restart Information Server Windows Services:
    - On the Information Server PC, press Win + R, type services.msc, and press Enter.
    - Locate and inspect the following services:

    • Information Server Service
    • Process Historian Ready Service (PH-Ready)
    • SQL Server Reporting Services (INFOSERVER)
    • Right-click each service and select 'Restart' (restart PH-Ready first, followed by Information Server Service).

  3. Verify Process Historian Server Health:
    - On the Process Historian PC (CS1075SR01), open the Process Historian Management Console.
    - Verify that the operational state is 'Active' (green icon).
    - Confirm that the Process Historian Data Access service is running.

  4. Reconnect Data Source in Information Server Web Portal:
    - Open Internet Explorer or Microsoft Edge and navigate to the Information Server portal (https://localhost/InformationServer).
    - Log on with Administrator credentials.
    - Navigate to 'Administration > Data Sources'.
    - Select the Process Historian data source (CS1075SR01).
    - Click 'Edit Connection' > verify credentials > click 'Test Connection'.
    - Confirm that the test reports 'Connection successful' and that the status indicator turns green ('Connected').

  5. Clear Cached Reporting Services Sessions:
    - In the Information Server portal, navigate to 'Administration > System Settings > Reporting'.
    - Click 'Clear Cache' to purge expired report datasets and forced stale renderings.
    - Regenerate the target report to confirm that recent tag and alarm data populate correctly.

Verification

  1. In Information Server, open a standard trend or message report covering the period of the outage.
  2. Verify that data curves and alarm records extend continuously up to the current minute without gaps.
  3. In Windows Task Manager on the Information Server host: observe that ReportingServicesService.exe actively processes SQL queries during report execution.
  4. Confirm that scheduled automated reports resume normal dispatch via email or file share.

Limitations and Operational Precautions

If Process Historian was offline for an extended duration, ensure that WinCC OS Servers have completed their store-and-forward buffer flush to PH before expecting data in Information Server. Verify that Windows user accounts and passwords used for the Information Server service account have not expired. Software maintenance agreements and license packages should be verified through an authorized Siemens distributor or the Siemens Industry Mall.

Engineer FAQ

Why did Information Server stop updating while WinCC runtime was fine?

Because WinCC displays live runtime data directly from controllers, whereas Information Server queries historical databases on Process Historian, which suffered a broken session connection.

What service manages communication between Information Server and Process Historian?

The Process Historian Ready Service (PH-Ready) and Information Server Service.

What network ports must be open between Information Server and Process Historian?

TCP port 1433 (Microsoft SQL Server) and TCP port 4840 (OPC UA).

Does restarting Information Server affect active plant control?

No. Information Server operates strictly as a supervisory reporting tier and has zero impact on controller or WinCC runtime execution.

Where can I check the data source connection status?

In the Information Server web portal under 'Administration > Data Sources'.

Technical References

Related Articles

Related Tags

  • Information Server
  • Process Historian
  • Data Sources
  • PH-Ready
  • Stalled Updates
  • PCS 7 V9.1
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