The monitoring mode parameter is used to enable and disable the sampling of a MonitoredItem, and also to provide for independently enabling and disabling the reporting of Notifications. This capability allows a MonitoredItem to be configured to sample, sample and report, or neither. Disabling sampling does not change the values of any of the other MonitoredItem parameter, such as its sampling interval.
When a MonitoredItem is enabled (i.e. when the MonitoringMode is changed from DISABLED to SAMPLING or REPORTING) or it is created in the enabled state, the Server shall report the first sample as soon as possible and the time of this sample becomes the starting point for the next sampling interval.