Rockwell Automation FactoryTalk Historian SE 4.0 Live Data Interface User Guide - Manual (Page 29)

Point Configuration Chapter 5
Rockwell Automation Publication HSELD-UM024A-EN-E–September 2013 29
NOTE
For information on exception reporting, refer to "Exception Reporting
and Compression Testing" in the FactoryTalk Historian SE Server
Reference Guide, available from Start > Programs > Rockwell Software >
FactoryTalk Historian SE > Help.
Output points control the flow of data from the Historian server to
any destination that is external to the server, such as the FTLD
server. The FTLD Interface uses
Location3=2 to indicate an output
point.
Outputs are triggered for UniInt-based interfaces. That is, outputs
are not scheduled to occur on a periodic basis. There are two
mechanisms for triggering an output, as described in the sections
that follow.
For Trigger Method 1, a separate trigger point must be configured.
The output point must have the same point source as the interface.
The trigger point can be associated with any point source, including
the point source of the interface. Also, the point type of the trigger
point does not need to be the same as the point type of the output
point.
The output point is associated with the trigger point by setting the
SourceTag attribute of the output point equal to the tag name of the
trigger point. An output is triggered when a new value is sent to the
Snapshot of the trigger point. The new value does not need to be
different than the previous value that was sent to the Snapshot to
trigger an output, but the time stamp of the new value must be more
recent than the previous value.
If no error is indicated, then the value that was sent to the trigger
point is also written to the output point. If the output is
unsuccessful, then an appropriate digital state that is indicative of
the failure is usually written to the output point. If an error is not
indicated, the output still may not have succeeded because the
Output Points
Trigger Method 1
(Recommended)