The OPC Diagnostics


The actual persistence settings for TOP Server OPC Diagnostics are under the TOP Server Administration settings, under the Event Log tab, as shown below:

OPC Diagnostics Log Settings:

  • Persistence Mode


    • Memory (no persistence) - The default option follows the legacy behavior of OPC Diagnostics and diagnostics are not persisted to file in this mode.
    • Single File - All diagnostics records will be persisted to one file only.
    • Extended Data Store - Enables spanning of diagnostics records across multiple files based on the other settings.

  • Max Records - Maximum number of records that the log can contain before the oldest records start being overwritten (Only available for Memory or Single File modes).
  • Log File Path - File system directory where log files will be stored.
  • Max single file size (KB) - Maximum size in KB that any one log file can contain. (Only available for Extended Data Store Mode).
  • Min days to preserve - Once log files are older than this number, they will be deleted.  (Only available for Extended Data Store Mode).

The OPC Diagnostics window can be accessed under View -> OPC Diagnostics in the TOP Server Configuration.


To specifically troubleshoot only OPC UA communications, the full set of filters are provided for enabling/disabling calls for OPC DA, OPC HDA and OPC UA.  From the OPC Diagnostics window, go to Diagnostics -> Filter.  By highlighting OPC DA and clicking “Uncheck Selected” and then also OPC HDA and clicking “Uncheck Selected”, you can restrict the diagnostics capture to only OPC UA events.


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