WinCC Tag Logging: Locating the Archive Database and Exporting to CSV

WinCC does not write tag logging values to comma-separated text files. From the legacy V6.x runtime up through the current WinCC Unified (TIA Portal V20) line, the historian is implemented as a Microsoft SQL Server database. Operators who need a portable artifact for reporting, statistical analysis, or hand-off to MES layers must deliberately export that data to CSV (or Excel). This reference describes exactly where the raw archive lives, which SQL files are touched, the export mechanisms shipped with each major version, and the license and configuration constraints that determine which path is available on a given project.

1. WinCC Tag Logging Architecture Overview

Tag Logging is split into two acquisition cycles, each persisted in its own SQL Server database:

• Tag Logging Fast – acquisition and archive cycle in the millisecond-to-second range. Used for fast-changing process values (pressures, flows, currents).
• Tag Logging Slow – acquisition and archive cycle in the seconds-to-minutes range. Used for slowly changing values (temperatures, counters, setpoints).

Both databases are created and maintained by the WinCC ArchiveManager service. The runtime writes via SQL Server, segments the tables over time, and rotates the on-disk files. Tag Logging in WinCC V6/V7 is a SQL Server Express or full SQL Server backend; the exact storage location is configurable in the project properties.

2. Where the Archive Files Live (V6 / V7)

The default path is inside the WinCC project directory, under the ArchiveManager subfolder:

C:\Siemens\WinCC\<ProjectName>\ArchiveManager
   ├── TagLoggingFast\
   │     ├── CC_LoggingFast.mdf
   │     └── CC_LoggingFast_log.ldf
   └── TagLoggingSlow\
         ├── CC_LoggingSlow.mdf
         └── CC_LoggingSlow_log.ldf

3. Verifying the Storage Path in the Project

Confirm the path that the active project is using:

1. Open the WinCC Explorer on the engineering or server station.
2. Right-click Computer → Properties → Graphics Runtime tab.
3. Note the Start picture and the Project path.
4. Right-click Tag Logging → Properties (or open the Tag Logging editor).
5. Open Archive Configuration → Timelines / Archives. The Storage location and per-archive path fields are shown here; in V7 the path can be redirected to a UNC share.

For a quick check from the command line:

dir /s "C:\Siemens\WinCC\<ProjectName>\ArchiveManager\*.mdf"
dir /s "C:\Siemens\WinCC\<ProjectName>\ArchiveManager\*.ldf"

If you do not see CC_LoggingFast.mdf/CC_LoggingSlow.mdf, the project is using a custom path or the runtime has not yet started archiving. Trigger an acquisition cycle (set a tag with archive=1 and wait one cycle) and re-check.

4. Why You Will Not Find a CSV on Disk

There is no .csv file written by Tag Logging in any version of WinCC. The runtime does the following with a logged tag value:

1. Stores the raw value into the in-memory archive buffer of the Tag Logging runtime.
2. Flushes the buffer at the configured archive cycle to the SQL segment table for the current time slice.
3. Closes and creates new segments as time progresses (segmentation is configured in the Archive Configuration editor).

Anything you can open in a text editor (*.csv, *.txt) must be produced by an explicit export step – either interactively in the operator faceplate, via the WinCC DataMonitor, via the WinCC OLE-DB provider, or via a user-written VBScript/C script in the runtime.

5. Exporting to CSV – Method Matrix

6. Interactive CSV Export from the OnlineTrendControl (V6.2 SP2+)

The fastest path. From WinCC V6.2 SP2 onward, the OnlineTrendControl offers a built-in export:

1. Open the WinCC Runtime containing the configured OnlineTrendControl picture.
2. Right-click inside the trend window.
3. Select Export Data → CSV File (or Export Data… in localized builds).
4. In the dialog, set:
   • Time range (Start/End – based on the trend's visible time base).
   • Columns (the curves currently assigned to the trend control).
   • Decimal separator and field separator (comma or semicolon – critical for European locales where Excel expects semicolons).
5. Choose the destination path (network share or local).
6. Confirm with OK. The runtime writes the CSV and opens it in the associated application.

Resulting file (header depends on curve names and timestamp format):

Timestamp;TagA;TagB;TagC
2024-05-12 08:00:00.000;12.34;0.987;1450
2024-05-12 08:00:01.000;12.36;0.989;1451

7. WinCC DataMonitor Export

WinCC DataMonitor is the web-based client for trend and alarm views. On V6.0 SP2 a DataMonitor client can connect and request a CSV export of a trend view. The data path is the same archive; the export is a server-side action.

1. Install the DataMonitor server component on the WinCC server (separate installation media in the WinCC setup).
2. Activate the DataMonitor web page in the WinCC project (Web Navigator / DataMonitor server settings).
3. Open the DataMonitor URL in Internet Explorer/Edge: http://<WinCCServer>/DataMonitor/
4. Log in with a user that has the DataMonitor – View and Export authorization.
5. Open Trends & Alarms → Trends.
6. Add the archive tags you want to export to a trend view.
7. Click Export → CSV. The browser downloads the file.

8. Scripted / Scheduled CSV Export (V6 / V7)

For unattended export – e.g. a daily CSV per shift – use VBScript inside a Global Action or a C action. The OnlineTrendControl exposes an Export method.

Setup prerequisites

• Configure a picture with an OnlineTrendControl bound to the desired archive tags.
• Open the picture in the runtime at least once to instantiate the control (it can be on a hidden start picture).
• Configure a time range; Export exports the currently displayed time range.

VBScript example – daily export

' Global action, triggered daily via scheduler
Dim sFile, sRange, oTrend, oTimeRange

Set oTrend = ScreenItems("MyTrendControl")

' Define a 24 h time range ending "now"
Set oTimeRange = CreateObject("TrendTimeRange")
oTimeRange.TimeBase = 1            ' vbSecond = 0, vbMinute = 1, etc.
oTimeRange.Begin = DateAdd("h", -24, Now)
oTimeRange.End   = Now

sFile = "D:\Exports\<ProjectName>_" & _
        Year(Now) & Right("0" & Month(Now), 2) & _
        Right("0" & Day(Now), 2) & ".csv"

oTrend.Export sFile, oTimeRange, 0   ' 0 = CSV
Set oTrend = Nothing

C-script variant (WinCC V7) – use the ExportCSV() method exposed on the IWinCCTrendControl COM interface. See the WinCC V7 Information System under Working with WinCC > VBA for Automated Configuration > Examples > Exporting Data from the WinCC OnlineTrendControl.

9. Direct Database Access via the OLE-DB Provider

Power users, Excel Power Query authors, and reporting tools such as SSRS or Power BI connect to the archive using the WinCC OLE-DB provider. This is the only method that does not require the data to be displayed in a picture first.

1. Confirm the WinCC AS-OS Engineering (a.k.a. Connectivity Pack) license is installed on the server.
2. Build a connection string:

Provider=WinCCOLEDBProvider.1;
Catalog=CC_LoggingSlow_<ProjectName>_<TimeStamp>;
Data Source=.\WinCC;
User Id=<WinCCUser>;
Password=<Password>;

3. Use the CC_READTABLE stored procedure or a direct SELECT against the dbo.TAG table (column VALUE, TIMESTAMP, QUALITY).
4. Push the result set to CSV from the consumer (e.g. bcp, Power Query's Export to CSV, or SSRS subscription).

Catalog names follow the pattern CC_<ArchiveType>_<ProjectName>_<YYYY-MM-DD hh-mm-ss-fff>. The catalog is created on first archive start and stays for the lifetime of the project unless explicitly re-created.

10. WinCC Unified (TIA Portal V20) – Logging Tags

From TIA Portal V16 onward, WinCC Unified is the new generation runtime. Tag Logging is configured in the HMI Tags editor of the Unified device, under Logging. The runtime persists values to a built-in SQLite or PostgreSQL store (project- and version-dependent). The Configuring logging tags (RT Unified) – TIA Portal V20 documentation describes the editor, the compression options, and the export from a trend control.

Key differences versus classic V6/V7:

• Logging tags are configured in the project tree under Runtime settings > Logging; there is no separate Tag Logging editor in Explorer.
• Cascading logging tags (a logging tag whose Source is another logging tag via the Compression setting) become invalid after certain project modifications and must be re-defined. The TIA Portal V20 documentation explicitly notes: "If you are using cascading logging tags by having defined a source under 'Compression', the reference becomes invalid due to the copy process. Redefine the [source]."
• Export is done from the Unified Trend Control: right-click → Export data → CSV/XLSX.
• The underlying database is not exposed by default; for external reads use the Unified OLE-DB / OPC UA Historical Access interface.

11. License Requirements Summary

12. Troubleshooting Matrix

13. Field-Proven Best Practices

• Pin your archive path. Always redirect Tag Logging to a dedicated, excluded-from-antivirus volume. Real-time virus scanning of .mdf/.ldf files can stall archive writes and corrupt the transaction log.
• Configure segmentation. Default behaviour keeps a single growing segment per archive; on long-running projects this produces huge .mdf files. Set a segment size (e.g. weekly or 200 MB) to keep individual files manageable and to make CSV exports bounded.
• Back up the archive periodically. The ArchiveManager is a live SQL Server. Use the SQL Server Agent job (or a script calling BACKUP DATABASE) to take a daily differential. A copy of the .mdf alone is not a recoverable backup without the .ldf.
• Standardize the CSV schema. Document the column order and the timestamp format (always use ISO 8601, yyyy-MM-dd HH:mm:ss.fff) in the export script. Consumers (Power BI, Python pandas) parse ISO 8601 without locale settings.
• Author VBScript exports with a fallback path. If CreateObject("TrendTimeRange") fails on a non-default browser station, the export silently produces an empty file. Wrap the call in On Error Resume Next and write an error line into the CSV.
• Use the OLE-DB provider for big exports. For ranges longer than 24 h, the OnlineTrendControl export runs out of memory. Stream from the OLE-DB provider with a chunked SELECT TOP n loop instead.

14. Quick Reference – File Locations by WinCC Version

15. Verification Checklist

After configuring a CSV export, run this checklist on the operator station:

1. Trigger the export and confirm the file appears at the configured path.
2. Open the CSV in Notepad – confirm the expected header and the locale-correct separator.
3. Open the CSV in Excel – confirm the columns parse into separate cells.
4. Compare the row count against the SQL source: SELECT COUNT(*) FROM dbo.<ArchiveTable>. They must match within one segment boundary.
5. Verify the timestamp column is in ISO 8601 form (or matches the documented export format).
6. If scripted: open the WinCC Global Script diagnostics and confirm no Runtime error line was logged.
7. On a Unified station: recompile, download, and re-run the export to rule out the broken-cascading-source case.

FAQ