Rockwell Automation FactoryTalk Historian SE ProcessBook 3.2 User Guide - Manual (Page 283)

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axis with changing FactoryTalk Historian exception data points until the
refresh interval expires and new data are received from the data set.
If a data set has a FactoryTalk Historian tag placeholder, then the data set
is refreshed every time a new value is received for the FactoryTalk
Historian tag placeholder.
Add Data Sets to Bars or Values in a Display
A single value from a data set may be added to a display as either a Value
or a Bar.
In general, queries can return many rows of results. The Value or Bar uses
only the data from the last row of the results for the column you select; the
rest of the results are discarded.
In many cases, you can use an ”r;order by” clause to control which rows
are returned first.
For example, the following query guarantees the most recent sample
appears in the ProcessBook Value field:
Select lab_val from Lab_Data where last_ID = ”r;BW”
Order by Sample_time asc
Run FactoryTalk Historian ProcessBook When
Data Sets Are Included
When you start FactoryTalk Historian ProcessBook and open an updating
display, it connects to your FactoryTalk Historian system and remains
connected until you close FactoryTalk Historian ProcessBook.
If you have configured data sets in a ProcessBook, FactoryTalk Historian
ProcessBook connects to a data source as soon as you open a display using
data set results.
The first time you use a particular data source, the external database may
ask you for login information through a login dialog box. After a