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

Configuring Local Tag Logging and Trend Visualization Without Process Historian in PCS 7

Configuring Local Tag Logging and Trend Visualization Without Process Historian in PCS 7

To view historical process trends in SIMATIC PCS 7 without a Central Archive Server (CAS) or Process Historian, configure local Tag Logging on the OS Server and display the data using the WinCC OnlineTrendControl in Graphics Designer. On the OS Server, configure process values in Tag Logging Fast (for acquisition cycles under 1 minute) or Tag Logging Slow (for cycles over 1 minute), define circular disk archive segment sizes, and assign the archive tags to trend curves on operator process screens.

Table of Contents

Executive Summary

Small to medium-sized SIMATIC PCS 7 installations often operate without a dedicated Central Archive Server (CAS) or enterprise Process Historian server due to cost or footprint constraints. Engineers must configure historical trend recording directly on local OS Servers to enable operators to review past batch runs, troubleshoot upsets, and evaluate process tuning. This guide explains the architecture of WinCC Tag Logging, the functional distinction between Fast and Slow archives, disk sizing calculation methods, and step-by-step trend curve configuration.

Architecture and Fundamental Mechanics

Tag Logging Architecture and Archive Mechanics on Local OS Servers:

  • WinCC Tag Logging Archive Tiers:
  • Tag Logging Fast: Optimized for high-speed cyclic data acquisition (cycles from 100 ms up to 1 minute). Stores data in binary compressed cache before committing to Microsoft SQL Server segment databases.
  • Tag Logging Slow: Designed for slower continuous variables (acquisition cycles > 1 minute, calculated averages, or event-driven archiving).
  • Circular Archive Segment Architecture:
  • Tag logging data is written into circular SQL database segments (.mdf and .ldf files) covering configured time intervals (e.g., 1 day per segment).
  • Oldest segments are automatically purged or overwritten once total disk storage allocation is reached, preserving continuous local operation without manual disk management.
  • Trend Display Mechanics:
  • Trends are rendered on OS Clients and Single Stations using the WinCC OnlineTrendControl ActiveX/.NET control.
  • The control connects via the OS Server Data package directly to the local Tag Logging SQL database, retrieving historical samples dynamically.

Step-by-Step Implementation Procedure

Step-by-Step Procedure to Configure Local Tag Logging and Trends:

  1. Enable Archiving on Technological Blocks in CFC:
    - In CFC, open the technological block (e.g., MonAnL - FB1845).
    - Open the properties of the process value output (PV_Out) -> select 'Archiving' -> choose 'Long-term archiving'.
    - During the next OS Compile, WinCC automatically creates the archive tag in Tag Logging.
  2. Configure Archive Cycles in WinCC Tag Logging:
    - Open WinCC Explorer -> open 'Tag Logging'.
    - In the tree, review 'Tag Logging Fast' and 'Tag Logging Slow'.
    - Set the acquisition cycle (e.g., 1 second) and archiving cycle (e.g., 1 second or on-demand).
  3. Configure Archive Sizing and Retention Limits:
    - In Tag Logging, right-click 'Archives' -> select 'Archive configuration'.
    - For Tag Logging Fast/Slow: Set max segment size (e.g., 500 MB) and max total size of all segments (e.g., 50 GB).
    - Set the time period covered by all segments (e.g., 30 days).
  4. Configure WinCC OnlineTrendControl in Graphics Designer:
    - In Graphics Designer, open the process graphic where trends are to be displayed.
    - From the Object Palette -> Controls -> insert 'WinCC OnlineTrendControl'.
    - In TrendControl Properties -> 'Trends' tab:
    • Add Trend 1 (e.g., 'Reactor Temperature').
    • Set Source Type to 'Archive tag'.
    • Browse and select the archive tag from Tag Logging.
    • Configure trend color, line width, and engineering unit scaling.
  5. Save Graphic and Test in Runtime:
    - Activate WinCC Runtime; open the picture.
    - Use the Trend ruler tool, zoom functions, and time range pickers to inspect live and historical curves.

Verification

To verify local trend archiving:
1. Activate WinCC Runtime on the OS Server or Client.
2. Allow the process to run for several minutes; verify that trend curves draw continuously from right to left.
3. Use the time-range button on the WinCC OnlineTrendControl toolbar to step back 1 hour; confirm historical data points display accurately.
4. Verify SQL database generation: check Windows Explorer under <ProjectDir>\ArchiveManager\TagLoggingFast to confirm .mdf/.ldf database segments are created.

Limitations and Operational Precautions

Operational precautions:
- Local OS Server Tag Logging should not be used as an infinite long-term repository; storage beyond 500 GB or 1–2 years can degrade OS Server runtime performance.
- For enterprise-wide, multi-year compliance archiving (e.g., FDA or environmental regulatory compliance), deploy a dedicated Process Historian.
- OS Archive licenses: Ensure the OS Server possesses sufficient 'WinCC / PCS 7 OS Archive' tag licenses in ALM (e.g., 512, 1500, or 5000 archive tags); exceeding license limits triggers periodic license deficit warnings.

Engineer FAQ

Can PCS 7 archive process tags without Process Historian?

Yes. The local OS Server contains a built-in Microsoft SQL Server Tag Logging database that logs historical values within configured circular storage limits.

What is the difference between Tag Logging Fast and Tag Logging Slow?

Tag Logging Fast is for high-speed acquisition cycles under 1 minute; Tag Logging Slow is for slower cycles equal to or exceeding 1 minute.

What control displays historical trends in WinCC?

The WinCC OnlineTrendControl, available in the Graphics Designer control palette.

What happens when local Tag Logging disk storage becomes full?

WinCC automatically deletes or overwrites the oldest database segment in circular fashion, maintaining continuous logging without crashing.

Do archived tags consume extra licensing?

Yes, archived tags consume WinCC / OS Archive licenses (configured in blocks of archive tags in Automation License Manager).

Technical References

Related Articles

Related Tags

  • Tag Logging
  • OnlineTrendControl
  • Historical Trends
  • Tag Logging Fast
  • Process Historian
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