Exporting WinCC Tags to Excel: VBScript and Data Logging Methods

Overview of WinCC-to-Excel Data Export Paths

Siemens WinCC provides three documented paths for moving runtime tag values into Microsoft Excel or a structured CSV file without purchasing third-party add-ons:

1. WinCC Trend Control export — runtime-driven, manual or triggered export from an HMI Trend view.
2. VBScript with FileSystemObject — programmable, event-driven, works in WinCC V7.x Runtime and TIA Portal WinCC RT Advanced/Professional.
3. TIA Portal Data Logging — function-block based CSV logging (TiaPortal V11+), ideal for cyclic 1 s+ logging and persistent archives.

All three paths produce a delimited text file (CSV) that Excel opens natively. None of them require Microsoft Office automation on the runtime PC; the file is generated server-side and Excel only renders it. The choice between methods depends on the trigger model (event vs. cyclic), number of tags, the HMI platform, and whether the source project uses WinCC V7 (classic) or TIA Portal WinCC.

Prerequisites

Reference the official Siemens manual set:

• SIMATIC HMI WinCC V7.5 — Programming and Reference Manual
• SIMATIC WinCC Engineering V18 — Manual
• WinCC V7.0 SP3 — VBScript Reference
• TIA Portal Openness / WinCC Scripting Manual

Method 1 — WinCC Trend Control Export

WinCC Trend Control ships with an export toolbar button that writes the currently displayed time window into a CSV or Excel-compatible file. This is the lowest-effort path and is suitable when the user is already viewing a trend and needs a snapshot.

Step-by-step configuration

1. Open Graphics Designer and insert an "Online Trend Control" (WinCC V7.x) or "WinCC Online Trend Control" (TIA Portal).
2. Configure the trend under Properties > Trends and add the WinCC tags you want to log.
3. Under Properties > Toolbar, enable the "Export data" button (icon: floppy disk with arrow). Verify the button shows up in Runtime.
4. Define the export format: CSV (separator: semicolon) is the default Excel-friendly format for European locales.
5. Trigger Runtime, populate the trend, click the export button, choose a writable path such as D:\Logs\ or C:\Users\Public\Documents\WinCCLogs\.

The output file contains a time stamp column, a status column, and one column per configured trend. Excel reads the file via Data > From Text/CSV with semicolon as the delimiter.

Method 2 — VBScript with FileSystemObject (Most Flexible)

VBScript runs on events such as tag value change, button click, or scheduler. The script reads tag values through HMIRuntime.Tags(...).Read and writes them as a CSV row via CreateObject("Scripting.FileSystemObject"). This works in WinCC V7.x and TIA Portal WinCC Runtime.

Minimal single-tag script

' Trigger: tag change event or button-click event in a WinCC screen
Dim f, ts, DataSet
Dim tagName, tagValue
tagName  = "Tag1"
tagValue = HMIRuntime.Tags(tagName).Read

DataSet  = CStr(Now) & ";" & tagValue & vbCrLf

Set f  = CreateObject("Scripting.FileSystemObject")
Set ts = f.OpenTextFile("D:\Logs\Export.csv", 8, True)   ' 8 = ForAppending, True = create if missing
ts.Write DataSet
ts.Close
Set ts = Nothing
Set f  = Nothing

Multi-tag single-row script

The most common field issue is that a script with sequential DataSet = ... assignments appears to overwrite the previous line. The fix is to concatenate the values into one string with a delimiter, then write once.

' Multi-tag capture: timestamp + N tags in one CSV row
Dim f, ts, DataSet
Dim sep, nowStr
sep    = ";"
nowStr = CStr(Now)

' Build the CSV row by concatenation (NOT overwriting)
DataSet = nowStr & sep
DataSet = DataSet & CStr(HMIRuntime.Tags("xxx1").Read) & sep
DataSet = DataSet & CStr(HMIRuntime.Tags("xxx2").Read) & sep
DataSet = DataSet & CStr(HMIRuntime.Tags("xxx3").Read) & sep
DataSet = DataSet & CStr(HMIRuntime.Tags("xxx4").Read) & vbCrLf

Set f  = CreateObject("Scripting.FileSystemObject")
Set ts = f.OpenTextFile("D:\Logs\Export.csv", 8, True)
ts.Write DataSet
ts.Close
Set ts = Nothing
Set f  = Nothing

Scaling to many tags

For ten or more tags, build a dynamic array rather than hard-coding concatenation. This keeps the script maintainable and avoids line-length limits.

' Array-driven multi-tag capture (TIA Portal WinCC / WinCC V7.x compatible)
Dim f, ts, header, line, i
Dim tagList
tagList = Array("MotorCurrent", "TankLevel", "Pressure", "Temperature", "FlowRate")

' Build header on first run only
Set f = CreateObject("Scripting.FileSystemObject")
If Not f.FileExists("D:\Logs\Export.csv") Then
    Set ts = f.CreateTextFile("D:\Logs\Export.csv", True, False)
    header = "Timestamp"
    For i = LBound(tagList) To UBound(tagList)
        header = header & ";" & tagList(i)
    Next
    ts.WriteLine header
    ts.Close
End If

' Append a new data row
Set ts = f.OpenTextFile("D:\Logs\Export.csv", 8, True)
line = CStr(Now)
For i = LBound(tagList) To UBound(tagList)
    line = line & ";" & CStr(HMIRuntime.Tags(tagList(i)).Read)
Next
ts.WriteLine line
ts.Close

Semicolon vs. comma delimiters

Excel's locale-dependent default CSV separator makes German/French locales open comma-delimited files incorrectly. Force semicolon separation, which is the Excel default in those regions and avoids the "all data in one column" symptom.

Method 3 — TIA Portal Data Logging (Cyclic Archive)

For cyclic logging at intervals as fast as 1 s, the recommended Siemens path is the Data Logging mechanism introduced in TIA Portal V11 SP2. This avoids the per-event script overhead and writes a managed CSV/SQLite archive directly from the HMI runtime.

Implementation outline

1. In the TIA Portal project tree, open HMI Tags and confirm the tags to log are present and accessible from the HMI.
2. Open Logs under HMI device, add a new Data log.
3. Add columns matching the tags you want logged; configure the data type per column (BOOL, INT, REAL, STRING).
4. Set logging mode to Cyclic or Event-triggered. For 1-second intervals select cyclic with a 1 s period; for a trigger bit select the trigger tag.
5. Configure the storage path. The default is on the HMI's local storage or a configured network share. Recommended: \Storage Card\Logs\ for Unified Comfort Panels, D:\Logs\ for PC Runtime.
6. Insert the function block LG_Datalog (TIA Portal V13+) in your PLC program or use the equivalent HMI-side DataLogTrigger system function to start/stop logging from the PLC.

The resulting CSV opens directly in Excel and contains a header row plus one row per logging cycle. Multiple header rows are not produced by Data Logging itself, which avoids the "second header" complaint common with manual VBScript logging.

Trigger Models Compared

Handling Multiple Headers in the CSV

A frequent follow-up question is: "how do I add a second header row to segregate data, for example by shift or by batch?" Two clean approaches:

1. Per-file headers: close the current CSV file at the shift boundary and open a new file named Export_ShiftA_20250115.csv. Each file receives its own header automatically because the script checks for file existence.
2. Inline separator rows: write a literal header row string before appending the data block, e.g. ts.WriteLine "=== Shift B start ===", then continue appending rows.

' Inline separator row example
Set ts = f.OpenTextFile("D:\Logs\Export.csv", 8, True)
ts.WriteLine ""   ' blank row
ts.WriteLine "=== Batch #" & HMIRuntime.Tags("BatchNumber").Read & " start at " & CStr(Now) & " ==="
ts.WriteLine header
' continue appending data rows below
ts.Close

Excel treats any line that does not match the column count as text. After import, use Data > Filter to hide the separator rows.

File Path, Encoding, and Locale

Three field-proven rules to avoid corrupted exports:

1. Always use an ASCII-safe absolute path. Avoid mapped network drives without persistent reconnection; UNC paths like \\SERVER\Share\Logs\ work but require the WinCC service account to have write permission. Siemens HMI Scripting reference, section "File System Access" documents the supported path conventions.
2. Use Unicode (UTF-8) or system ANSI. CreateTextFile(path, overwrite, unicode) with unicode=False writes ANSI (matches Excel on the same machine). Pass unicode=True if the file will be opened on systems with different code pages.
3. Encode numeric tags as strings before concatenation. CStr(HMIRuntime.Tags("Pressure").Read) prevents type-mismatch runtime errors when the PLC briefly writes an invalid value.

Error Codes and Failure Modes

Verification Procedure

1. Start WinCC Runtime and force the trigger event (click the configured button, set the trigger tag in the PLC, or wait for the scheduler).
2. Confirm the target CSV exists at the configured path. Open it in Notepad to verify line count, separator, and that each row contains all expected tag values.
3. Open the CSV in Excel using Data > From Text/CSV. Confirm that columns align with the configured tags, that the timestamp column parses as a date, and that numeric columns format correctly.
4. For Data Logging, check the HMI's Diagnostics > Logs view to confirm the log status is Running and the cycle count is incrementing.
5. Run a stress test: trigger the script 1,000 times in a loop using the scheduler and confirm that no rows are dropped and no file lock errors occur.

Troubleshooting Decision Tree

1. Is the file being created at all? If not → check path permissions and trigger event wiring.
2. Is the file created but empty? → the tag read is failing; check tag spelling and PLC connection.
3. Are values wrong (not what the PLC shows)? → confirm tag is mapped to the correct PLC address; verify update cycle.
4. Are values correct but only one tag per row? → fix the VBScript concatenation pattern as shown above.
5. Does Excel not split columns? → switch delimiter to semicolon or use Text-to-Columns wizard.
6. Does the file grow huge? → add rotation by renaming on size threshold or by scheduler.

Best Practices and Field Tips

• Use a dedicated folder. Create D:\Logs\ (or platform-specific equivalent) before the first run. Do not write to C:\Program Files\ or to a network share that may be temporarily offline.
• Include a header row only once. Use a file-exists check to write the header on the first record only.
• Format timestamps deterministically. Format(Now, "yyyy-mm-dd hh:nn:ss") sorts correctly in Excel; Now uses locale-dependent formatting.
• Convert numbers with CStr. Always wrap tag reads in CStr(...) to handle type changes gracefully.
• Free COM objects. Set f and ts to Nothing after use to release file handles. Repeated opens without release cause WinCC to exhaust file handles within hours.
• For high-frequency logging, prefer Data Logging. VBScript with a 1 s scheduler works but is less efficient than the native data log mechanism.
• For Trend Control export, configure decimal places on the trend axis to control CSV precision.
• Document the trigger in the screen's comment so future maintainers know whether the script is button-driven, tag-driven, or scheduler-driven.

Reference: Function and Property Summary