About the log history service

The Log History Service keeps a History of Niagara log records when it is enabled. This service maintains a buffered history (“LogHistory”) of some of the messages seen in the station’s standard output. This can be very helpful when you are troubleshooting problems with a station. If a station has Log History Service enabled, you can check the log history for recent error messages. Refer to the Platform Guide section “Application output” for more information about output messages.

The Log History Service is available in the History Module. The easiest way to add this service (if not already present) is through a simple drag and drop from the History Palette (under the HistoryService) onto the services area of the nav side bar pane, as shown in Figure 132.

Figure 132. Adding log history service

You can edit the Log History Service properties and set configuration properties in the property sheet, as shown in Figure 133.

Figure 133. Log history service properties

In addition to the standard HistoryConfig properties, the following properties are available for editing:

Enabled

select the true option to enable or the false option to disable the Log History Service.
Minimum Severity

you can choose the level of output that you want to record by setting the log level Minimum Severity property. This property is the lowest-level station output message that you want to log. The default log level for Minimum Severity is Error. You can change this to Warning., Trace, or Message.