MP 277 Alarm Logging to CSV: WinCC flexible Configuration

Overview

The Siemens MP 277 Multi Panel (catalog family 6AV6 643) supports persistent alarm logging through WinCC flexible 2008 SP2 and later. Two on-device storage formats are available for alarm logs: the binary RDB (Runtime Database) container and the plain-text CSV file. CSV is the format most engineers require when alarm history must be opened directly in Excel, imported into MES historians, or parsed by external scripts without an RDB viewer.

WinCC flexible exposes the storage format as a per-log property. The configuration path is Project → Historical Data → [Alarm Log] → Properties → Storage location, and the default value File - RDB can be switched to File - CSV. The behavior is documented in the WinCC flexible online help under Working with WinCC flexible → Working with alarms → Alarm logging → Basic principles → Storage location for log files and in the WinCC flexible 2008 SP2 Compact / Standard / Advanced Operating Manual.

Prerequisites

Confirm the panel image version on the MP 277 itself: Start Center → Settings → OP Properties → Version. The image version must be newer than or equal to the version that produced the project in WinCC flexible; otherwise the CSV log tag will be downgraded to RDB at compile time and a warning is raised in the build log.

Storage Location Options

WinCC flexible offers four storage targets for any log (alarm or data). They are mutually exclusive per log entry:

The MP 277 cannot use the Database (ODBC) target — that storage class requires RT Professional / PC Runtime. Stick to File - RDB or File - CSV on panel hardware.

Step-by-Step Configuration

1. Open the WinCC flexible 2008 SP2 project for the MP 277.
2. In the project tree, expand Historical Data.
3. Right-click and select Add Log → Alarm Log. A new entry such as AlarmLog_1 is created. The log name is the file stem on the panel; do not embed spaces or special characters other than _ and -.
4. Open the Properties dialog of the new alarm log (double-click or right-click → Properties).
5. Switch to the Storage location tab (in German: Speicherort).
6. Change the Storage location drop-down from File - RDB to File - CSV.
7. Choose the storage medium:
   • \Storage Card\Logs\ — external CF / PC card on 10" / 12" MP 277
   • \USB\Storage\Logs\ — USB stick on the front USB host
   • \Flash\Logs\ — internal flash (default, lowest capacity; approx. 6 MB free after image)
8. Set the Log size (entries) and the segment behavior. For CSV, choose Segmented, switch segment when size reached to produce one CSV per segment; each segment is named <logname>_<YYYYMMDD>_<HHMMSS>.csv.
9. Click OK to close the Properties dialog.
10. Open Alarm Classes in the project tree (Alarms → Settings → Alarm Classes) and verify the alarm classes you intend to log are assigned to the alarm log. Without assignment, no events are written even if the log exists. The MP 277 ships with the classes Errors, Warnings, System, and Information; custom classes (e.g. Operator Action) must be created here first.
11. Compile the project (Project → Compiler → All) and check the Output window for warnings about unsupported log targets.
12. Transfer the runtime to the MP 277 via Ethernet or MPI.

Alarm Class Assignment

A common commissioning failure is that the alarm log exists but the file stays empty. The cause is almost always an unassigned alarm class. WinCC flexible requires an explicit mapping between an alarm class and each log that should record it.

To assign classes: Historical Data → [your Alarm Log] → Properties → Alarm Classes. Tick every class whose events should be appended. If only the Warnings box is ticked, Errors will not be logged even if they fire and appear in the live alarm view.

Alternative: RDB to CSV Conversion via CopyLog

If a deployment must keep the high-performance RDB writer on the panel and produce CSV only for offline analysis, the system function CopyLog converts the file on demand.

Function signature (WinCC flexible help, function group Logging):

BOOL CopyLog(
  HMI_Log   hLog,        // handle of the source log
  LPCTSTR   pszSourceFile, // path of the RDB file, e.g. "\\Flash\Logs\AlarmLog_1_20240101.rdb"
  LPTSTR    pszDestFile    // target CSV path, e.g. "\\USB\Storage\Logs\AlarmLog_1_20240101.csv"
);

Typical VBScript inside a function:

' Trigger a manual export on a button press
Dim sSrc, sDst, bRet
sSrc = "\\Flash\Logs\AlarmLog_1_" & Format(Now,"yyyymmdd") & ".rdb"
sDst = "\\USB\Storage\Logs\AlarmLog_1_" & Format(Now,"yyyymmdd") & ".csv"
bRet = CopyLog(SmartTags("AlarmLog_1_Handle"), sSrc, sDst)
If bRet = False Then
  ShowSystemAlarm "CopyLog failed: " & GetLastError()
End If

The MP 277 must have both the source RDB and the destination CSV path mounted; CopyLog cannot cross an unmapped network share. Per the WinCC flexible runtime reference, the function returns FALSE if the destination cannot be written or if the source handle is invalid; the panel raises system alarm 140001 / 140002 in those cases.

File Naming and Path Conventions

The default delimiter is ; in German and English Windows locales, which avoids collision with the decimal comma. To produce comma-delimited output that opens natively in Excel for North American customers, switch the Windows regional settings of the engineering PC to English (United States) before compile — WinCC flexible encodes the delimiter into the runtime image at compile time, not at runtime.

Verification

1. After transfer, the MP 277 should restart in runtime. Trigger a test alarm (e.g. set a tag that drives a configured alarm bit).
2. After three log entries are written, the panel creates the CSV file on the chosen storage medium — the segment-rotation threshold protects against premature flushes that would fragment the log.
3. On the panel, exit runtime, open Start Center → File Browser and navigate to the log path. Confirm the file timestamp matches the test cycle.
4. Remove the storage medium (or use ProSave to copy the file) and open it in Excel or Notepad. The header row must be present, dates parseable, and each event occupies one line.
5. If the file is missing, repeat the test with the project's Simulator on the engineering PC — this isolates whether the log configuration itself is wrong versus a panel-specific issue (firmware, media, path).
6. Check the Output window of the WinCC flexible compiler for message 140001 - Log: storage location not supported; that indicates the panel image is older than the project and the runtime silently falls back to RDB.

Troubleshooting Matrix

Migration to TIA Portal

For MP 277 panels targeted by future TIA Portal / WinCC (TIA) engineering, alarm logging behavior is preserved. In TIA Portal V16 and later, an MP 277 can be migrated via Project → Migrate project; the original File - CSV storage target becomes the Tag logging / Alarm logging entry in the TIA Portal project with a Storage medium of File (CSV). The MP 277 image must be updated to the matching TIA image (image version V 01.04.00.00_01.05 or later) before the migration is accepted.

No additional log configuration is required — the on-panel file path and naming convention are preserved. Operators continue to use Start Center → File Browser to retrieve CSVs.

Cross-Platform Reference

The same three-record minimum write behavior is documented for Proface GP-Pro EX alarm export, which performs its first CSV flush after the third logged event. See the Proface Export Alarm Data operation guide. Although the controller is a different vendor, the design rationale (buffered write to avoid power-loss corruption) is shared, and the same diagnostic step (force three test events before declaring a panel-side failure) applies.

Field-Commissioning Checklist

• Panel image ≥ project build date
• Storage medium inserted and recognized in Start Center → File Browser
• Free space ≥ 2× the largest expected segment size
• At least one alarm class assigned to the alarm log
• Storage target set to File - CSV in log properties
• Compile clean, no warning 140001
• Test event triggered and CSV verified on the medium after the third record
• If CopyLog is used, both source RDB and destination CSV path exist and are writable