Resolving WinCC Flexible Datalog Archive Errors on MP277 Panels

This technical reference addresses the most common WinCC Flexible datalog and archiving failures observed on the SIMATIC MP277 HMI panel: corrupted segmented circular logs, the recurring system alarm 80045, the network-side error 59 during backup copy, and the documented MP277 entry-count ceiling. It consolidates field-proven configuration limits, script function reference, and step-by-step recovery procedures suitable for commissioning engineers and maintenance technicians.

1. MP277 Datalog System Limits

The MP277 panel enforces hard limits on datalog size and project archive count. Exceeding these limits produces silent truncation, write failures, or repeated system alarms during runtime. The limits are documented in the WinCC Flexible help system under "System Limits" and in the SIMATIC HMI Manual Collection.

The 10,000-entry ceiling applies to the total entries across every segment of a segmented circular log, not per segment. If the datalog is configured as a non-segmented circular log, the entire 10,000-entry budget is consumed by a single file. A 10-second acquisition rate at 10,000 entries yields roughly 27.7 hours of continuous history before wraparound; this is the practical limit when the application must survive an overnight plant outage without backup.

2. Datalog Configuration in WinCC Flexible

A WinCC Flexible datalog is a sequence-based file written to the panel's file system. Each log has a storage location, an entry schema (tag list), a cycle or trigger, and a size policy (circular or sequential; segmented or non-segmented).

2.1 Recommended Configuration for a Temperature Log

1. Open the project in WinCC Flexible 2008 and select Logs > Data Logs.
2. Create a new log named Temperature.
3. Add a single tag column of type REAL or INT matching the PLC address (e.g., DB1.DBD0).
4. Set Logging mode to Circular log.
5. Enable Segmented log with 2 segments × 5,000 entries each (10,000 total, within limit).
6. Set the Acquisition cycle to 1 second for trend fidelity; let the Logging cycle be 10 seconds to reduce file I/O.
7. Bind the log to a Trend View for operator visualization.
8. Configure a tag trigger to start/stop logging on a process condition (e.g., line running).

2.2 Acquisition vs. Logging Cycle

Many integrators conflate acquisition and logging. The Acquisition cycle determines how often Runtime samples the tag value into a buffer; the Logging cycle determines how often the buffered value is committed to the log file. For a temperature signal, a 1 s acquisition with 10 s logging is sufficient for trend review and reduces flash wear by a factor of 10. When the logging cycle exceeds the acquisition cycle, Runtime writes the most recently acquired value to the log.

3. The ArchiveLogFile Function

The ArchiveLogFile function moves (or copies, depending on parameters) a closed log segment from the panel's local storage to a backup location such as a network share, USB drive, or SD card. It is invoked from a script and is the most common failure point when the log exceeds runtime limits.

3.1 Function Prototype

Syntax
  ArchiveLogFile <ArchiveName>, <LogName> [, <DestinationPath> [, <FunctionCode>]]

Parameters
  ArchiveName  : STRING  - Internal archive name declared under "Logs > Logs" in the project.
  LogName      : STRING  - Name of the log file (without path) to archive.
  DestinationPath : STRING - Target directory. UNC paths supported: \\Server\Share\Folder.
  FunctionCode : INT (optional)
                 0 = Copy  (default; source file remains)
                 1 = Move  (source file deleted after successful copy)

Return value
  0            : Success
  <> 0        : Error — Runtime emits system event 80045

3.2 Sample Script: Move Temperature Log on Trigger

' VB script scheduled daily at 23:59:59
Dim hmiDataLog, hmiMove, sResult
hmiDataLog  = "Temperature"             ' Log name as defined in project
hmiMove     = 1                          ' 1 = move (delete source after copy)
sResult     = ArchiveLogFile("hmiDataLog", hmiDataLog, "\\BackupNAS\PlantLogs\Temperature", hmiMove)

If sResult <> 0 Then
    ' Trigger user-defined event for SCADA notification
    SetBit("DB_Alarm.ArchiveError", 1)
End If

4. System Event 80045 — Diagnosis and Resolution

System event 80045 ("Archiving of log <name> was not successful") is the panel's generic alarm for any ArchiveLogFile failure. It carries no detail on root cause; engineers must work the troubleshooting matrix below before assuming a network fault.

4.1 Recovery Procedure for Repeated 80045

1. Stop WinCC Flexible Runtime on the MP277 from the panel's service menu (Start > Settings > Control Panel > Transfer or via RT_OFF script).
2. Connect to the panel via ProSave or Ethernet and open the file system.
3. Navigate to \Storage Card\Logs\Temperature\ (or wherever the log is configured).
4. Delete the suspect log file(s). If two extra files appear (recovery markers), delete them as well.
5. Verify the destination share is reachable and writable; create a 1 KB test file from the panel using FileWrite in a diagnostic script.
6. Restart Runtime and trigger the archive script manually.
7. Monitor the system alarm window for 30 minutes; if 80045 does not recur, the file was corrupt.

5. Network Error 59 — File-Size Triggered Archive Failure

When the log segment grows large — typically beyond 200–300 KB at 10 s logging over 24+ hours — SMB transfers to certain NAS devices (Western Digital My Book / My Cloud series is a confirmed offender) begin to fail with Error 59: An Unexpected Network Error Has Occurred. The MP277's CE 5.0 TCP/IP stack has a small default SMB session buffer; large single-file writes stall the session and the server closes the handle.

5.1 Mitigations for Error 59

1. Cap segment size: Reduce entries per segment to 2,000–3,000. At a 10 s logging cycle, a 2,000-entry segment is roughly 80–120 KB and stays well under the buffer limit.
2. Increase rollover frequency: Trigger a segment close on shift change or every 4 hours via a scheduled script using CloseAllLogs or by toggling a tag that resets the trigger.
3. Stage to local USB first: Copy to a USB stick on the panel, then use a host-side script to push files to the NAS. This decouples the panel's SMB from the NAS's SMB implementation.
4. Use FTP instead of SMB: Configure the NAS for FTP and replace ArchiveLogFile with a manual FileCopy to an FTP-mapped local path. Verify the panel's FTP client is enabled in the image.
5. Update NAS firmware: Vendor firmware updates frequently address SMB session timeout issues. Pin the firmware version in your change log.

5.2 Sanity-Check Script for Destination Path

' Diagnostic: write a 1 KB file to the destination path; if it fails, the share is unreachable.
Dim sResult, i
i = 0
Do While i < 10
    sResult = FileWrite("\\BackupNAS\PlantLogs\Temperature\ping.txt", "test", 4)
    i = i + 1
Loop
If sResult <> 0 Then
    SetBit("DB_Diag.NAS_Unreachable", 1)
End If

6. Segmented Circular Log Design Pattern

The segmented circular log is the only sustainable long-term logging topology on MP277. A non-segmented circular log fills to 10,000 entries, wraps in place, and offers no per-segment file the archiver can move. A non-circular (sequential) log fills the file system and never wraps, eventually halting writes. The segmented circular log combines bounded disk usage with discrete archive units.

6.1 Sizing Formula

Total history time  =  (EntriesPerSegment × NumberOfSegments × LoggingCycle) / 1
Example (10 s cycle, 5 segments × 2,000 entries):
                    =  2,000 × 5 × 10 s = 100,000 s ≈ 27.8 h

Disk footprint      ≈  EntriesPerSegment × NumberOfSegments × RowBytes
Example (REAL tag, ~24 bytes/row CSV):
                    ≈  2,000 × 5 × 24 B = 240 KB

6.2 Recommended Settings for Temperature Logging

7. Long-Term Archiving Strategy

For retention beyond the on-panel 27-hour window, the project must include scheduled archive jobs that copy each closed segment to durable storage. The official Siemens reference document for long-term logging with WinCC flexible describes a project structure that pairs the on-panel Data_Logs_Trend_View log with an external file system for persistence.

Reference: How do you do long-term logging with WinCC flexible? (Siemens Support, PDF)

7.1 Recommended Project Architecture

1. Define the on-panel log as a segmented circular log (Section 6).
2. Schedule a daily ArchiveLogFile job for each log to copy closed segments to a NAS share.
3. On the SCADA host, schedule a PowerShell or batch script that ingests new CSV files into a SQL database or historian.
4. Maintain a 30-day retention policy on the NAS with automatic cleanup of files older than 30 days.
5. For TIA Portal migration, use a viewer tool such as WinCCflexLogViewer to validate archive continuity before cutover.

8. Common Scripting Errors and Their Signatures

9. Verification Checklist After Configuration Change

After modifying any datalog, archive script, or destination path, run the following verification sequence before returning the panel to production.

1. Compile and download the project to the MP277 and restart Runtime.
2. Confirm the log file appears in \Storage Card\Logs\<LogName>\ after one logging cycle.
3. Trigger the archive script manually and confirm a file appears at the destination share.
4. Inspect the destination file with a CSV editor; verify the semicolon-delimited schema matches the tag list.
5. Force a wraparound by writing 11,000 entries and confirm Runtime clamps to 10,000 without alarm.
6. Disconnect the network share and re-trigger the script; confirm 80045 fires within one cycle and recovery occurs within 300 s of reconnection.
7. Reboot the panel; confirm scheduled archive resumes without operator intervention.
8. Open the log in the Trend View and verify continuous history across the segment boundary.

10. Migration Path to TIA Portal

Projects designed for WinCC Flexible are migrated to TIA Portal WinCC Comfort/Advanced via the porting tool. The datalog structure is preserved, but the script API changes: ArchiveLogFile becomes LogTag with separate archive job configuration under "Historical data > Data logs". The 10,000-entry MP277 limit does not apply to TIA Comfort Panels — TP700 Comfort supports 100,000 entries per log, TP1500 Comfort 500,000. Plan capacity sizing accordingly during migration.

Validate the migrated archive data by exporting one day's CSV from the new TIA project and comparing the row count against the WinCC Flexible source.

11. Summary of Hard Constraints

Compliance with these constraints prevents 80045, error 59, file corruption, and silent data loss. When the application demands retention beyond the MP277 ceiling, externalize the archive job to a host-based historian and use the panel only as a real-time trending surface.