C135 PCS 7 (PCS7)
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Querying Long-Term Process Historian Archive Data in WinCC Controls Without Information Server in PCS 7

Querying Long-Term Process Historian Archive Data in WinCC Controls Without Information Server in PCS 7

SIMATIC WinCC Operator Stations in PCS 7 connect natively to the SIMATIC Process Historian (PH) database without requiring SIMATIC Information Server (IS). WinCC TrendControl and AlarmControl automatically query the Process Historian whenever an operator selects a historical time range that falls outside the short-term local archive buffer configured on the WinCC OS Server. Seamless long-term trend and alarm visualization operates transparently across the terminal bus, provided the Process Historian is active, configured within the central SIMATIC Manager multiproject, and synchronized with the redundant OS server pair.

Table of Contents

Architecture of Long-Term Archiving with Process Historian

In modern SIMATIC PCS 7 architectures, process data and alarm logs are segmented into two distinct operational horizons:

  • Short-Term Local OS Server Buffers: The WinCC OS Server pair maintains cyclic circular archives in Microsoft SQL Server (e.g., storing 1 to 6 months of process data and alarm segments locally in ArchiveManager). This buffer ensures rapid operator screen updates and local redundancy synchronization.
  • Long-Term Enterprise Archiving (Process Historian): A dedicated central server running SIMATIC Process Historian (PH) continuously ingests segmented archive swaps from all connected OS servers. The PH server stores years of historical telemetry in an optimized, multi-terabyte SQL Server database structure.
  • Role of SIMATIC Information Server (IS): Information Server is a web-based reporting application used to generate scheduled compliance documents, PDF reports, and executive dashboards. It is not a prerequisite for operators to view historical archive data on standard WinCC runtime stations.
+-------------------------------------------------------------------+
|               PCS 7 Process Historian Query Flow                  |
+-------------------------------------------------------------------+
|  WinCC Operator Client (TrendControl / AlarmControl)              |
|                             |                                     |
|                             v                                     |
|  Selects Time Range > 6 Months Ago (Outside Local OS Cache)       |
|                             |                                     |
|                             v                                     |
|  WinCC OS Server (Seamless OLE-DB Handshake)                      |
|                             |                                     |
|                             v                                     |
|  SIMATIC Process Historian Server (Central SQL Database)          |
|                             |                                     |
|                             v                                     |
|  Returns Historical Data Directly to WinCC Client Display         |
|  (No Information Server or Manual DB Attachment Required)         |
+-------------------------------------------------------------------+

Native WinCC OS Query Mechanisms Without Information Server

WinCC contains an integrated communication mechanism that connects the OS Server runtime transparently to Process Historian:

  1. Automatic Database Routing: When a client requests historical data from WinCC Tag Logging or Alarm Logging, the local OS server first checks its local segment directory. If the requested timestamps precede the oldest locally stored segment, the OS runtime automatically routes the query to the Process Historian across the Terminal Bus.
  2. Transparent Trend Streaming: The operator does not need to execute manual "Connect Database" or "Attach Archive" commands; WinCC TrendControl queries the PH SQL database via optimized internal stored procedures and streams the vectors directly into the trend graph.
  3. Journal List Queries: Similarly, WinCC AlarmControl seamlessly queries the PH database when displaying the long-term message journal.

Configuring Historical Time Ranges in WinCC TrendControl

To retrieve and display multi-year data from Process Historian on a WinCC client:

  1. In WinCC Graphics Designer, open the process graphic containing the WinCC TrendControl (or open the runtime trend window).
  2. Double-click the TrendControl to open its Properties dialog.
  3. Select the Time Axes tab:
    * Under Range, select Start/End time or Time range.
  4. In the runtime control toolbar:
    * Click the Select Time Range button (calendar icon).
    * Specify a start date that exceeds the local OS buffer (e.g., 12 months in the past) and define the end date.
  5. Click Apply.
  6. The WinCC OS Server forwards the query to Process Historian. Within seconds, the historical trend curve renders across the selected multi-month window.

Retrieving Long-Term Alarm Logs in WinCC AlarmControl

To view historical messages archived in the Process Historian:

  1. In WinCC Runtime, navigate to the standard Alarm system screen (@AlarmJour.pdl or custom alarm display).
  2. Select the Long-Term Archive List or Journal view.
  3. Click the Selection... button (funnel icon) in the AlarmControl toolbar.
  4. In the Selection criteria dialog:
    * Select the Date / Time criterion.
    * Define the query window: e.g., Set Date/Time < Current Time - 180 Days or specify an exact historical date range from the previous year.
  5. Click OK.
  6. WinCC AlarmControl queries the Process Historian and displays all matching historical alarms, including incoming timestamps, operator acknowledgments, and outgoing recovery timestamps.

Verification

Confirm that Process Historian queries execute successfully without Information Server:

  1. Process Historian Health Verification:
    * Open the Process Historian Management Console on the PH server.
    * Verify that the PH status indicates Active and that the OS server data ingestion state is Ready.
  2. WinCC Client Trend Interrogation:
    * In WinCC Runtime, open a trend control linked to an archived analog tag.
    * Shift the time window backward to a date where local OS segments have been deleted.
    * Confirm that the trend line continues to render historical samples retrieved from Process Historian.
  3. Network Traffic Inspection:
    * Inspect network activity on the Process Historian terminal bus adapter during a large historical query.
    * Confirm bidirectional data flow over TCP Port 1433 (SQL Server) or proprietary PH communication ports.

Limitations and Operational Precautions

  • Terminal Bus Bandwidth Constraints: Querying years of high-frequency archive tags (e.g., 100 ms samples over 12 months) transmits massive datasets across the Terminal Bus, potentially causing temporary client UI lag. Use reasonable time ranges and appropriate data compression.
  • Tag Logging Archive Licensing: Storing variables in WinCC and Process Historian requires appropriate Archive Tag licenses on the WinCC OS Server. Ensure sufficient archive tag capacity is licensed in Automation License Manager.
  • Process Historian Redundancy: In a redundant PH architecture, queries automatically fail over between PH Server 1 and PH Server 2 without operator intervention.
  • Local Archive Deletion Rules: Never manually delete local archive files (.mdf/.ldf) in Windows Explorer on the OS server to force queries to the PH; WinCC handles segment expiration automatically according to the configured circular archive sizing.

Engineer FAQ

  • Can WinCC display trends from Process Historian if Information Server is not purchased?
    Yes, WinCC TrendControl connects natively to Process Historian via the OS Server runtime to display long-term trends without requiring Information Server.
  • What is the primary purpose of SIMATIC Information Server if WinCC can query PH directly?
    Information Server provides automated, web-based reporting, scheduled email reports, and Excel/PDF report generation, which are separate from interactive operator runtime screens.
  • Does the operator have to manually attach Process Historian databases in WinCC?
    No, WinCC automatically routes queries to Process Historian when the requested time range is older than the locally stored WinCC circular archive segments.
  • How long does WinCC OS store data locally before routing queries to Process Historian?
    This depends entirely on the circular archive configuration in WinCC Tag Logging and Alarm Logging (typically configured between 1 month and 6 months).
  • Does querying Process Historian from WinCC require additional client licenses?
    No, standard WinCC RT clients utilize their existing OS client connection licenses to query historical data through the OS server.
  • Can I query Process Historian alarms using standard WinCC AlarmControl filters?
    Yes, using the Selection dialog in AlarmControl, operators can filter by date/time, message class, area, or tag name, and the query executes across the PH database.
  • What happens if the Process Historian server is temporarily powered down?
    WinCC continues to display data stored in its local circular buffers, but attempting to query historical time ranges preceding the local buffer will return blank curves.
  • Where is the connection to Process Historian configured in the PCS 7 project?
    In SIMATIC Manager, the Process Historian station is inserted into the Multiproject, and OS servers are linked via the 'Process Historian' tab in the OS Project Editor.
  • Does Process Historian support redundant server configurations?
    Yes, Process Historian supports hardware redundancy with a witness node, ensuring continuous data recording and query availability.
  • Can custom SQL queries or third-party tools access the Process Historian database directly?
    Yes, external applications can query Process Historian using OLE-DB, ODBC, or OPC HDA, provided appropriate database user credentials and read-only views are utilized.

Technical References

  • Siemens Industry Online Support (SIOS) Portal: SIMATIC Process Historian Administration and Operating Manual (Entry ID: 109744907).
  • SIMATIC PCS 7 Operator Station Engineering Guide, Siemens AG.
  • SIMATIC WinCC V7.4 / V7.5 Information System - Archiving Process Data.

Related Articles

Related Tags

PCS 7, WinCC, Process Historian, Information Server, Tag Logging, Alarm Logging, TrendControl, Long-Term Archiving

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