Help Articles: Managing WinCC OA Log Files

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The log files in WinCC OA contain a wealth of information about the running system.  The log viewer is handy during development when troubleshooting bad IO address, scripting syntax errors, etc. All of those messages are written to the appropriate log file in the <project>/log folder. These files have names like:

  • PVSS_II.log
  • WCCOActrl1.log
  • WCCOAui0.log
  • WCCOAs7.log

Defining Log File Size

As these files grow, they have a maximum size that you can define.

  • The size of the PVSS_II.log file, as well as pmon.<hostname> log, is monitored by the Pmon. The file size can be defined via the config entry maxLogFileSize in the [general] section (default = 10 MB, 0 = unlimited). If the defined size is exceeded the file is renamed  PVSS_II.bak.

The PVSS_II.log file is not the only file it monitors, it also monitors the rest of the log files in that folder. In the WinCC OA help file section, there is more information:

  • Thereafter a possibly existing shell script (batch file) with the name postLogFileHandler and extension .sh (under Linux) or .cmd (under Windows) is executed. This file has to be located in the directory <proj_path>/bin. The name of the PVSS_II.bak file is passed as a parameter.

This attached file is executed automatically if it exists in the <project>/bin folder (remove the .removeme extension!) whenever any of the log files exceed the specified size (default 10MB).  In the attached version of this file, it zips the .bak file and emails it to an interested party, then deletes the zip file to clean up after itself.


If your log files are filling up, there is probably a severe problem with your application. You might not get alarms for whatever is happening and/or your application might be somewhere that you do not have access to every day.  This little batch file would send you the full log file so you can evaluate the issue and decide if it is something you should be fixing right away, or just to keep an eye on for the future.

Test it carefully by running “postLogFileHandler.cmd ../log/PVSS_II.log” inside the <project>/bin folder from a command prompt to make sure your email stuff is correct and you receive the file.

You can download the file here.

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