Calculated data – Rockwell Automation FactoryTalk Historian SE DataLink 4.2 User Guide User Manual

Page 51

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FactoryTalk Historian DataLink Functions

43

where the column of timed data appears in the column to the right, based
on time stamps retrieved for a different tag in the first two columns at left.

Calculated Data

Returns one or more evenly-spaced, calculated values based on
FactoryTalk Historian point values or evaluated expressions. A range of
different calculation and sampling preferences are provided.

Separate dialog boxes are provided for Calculated Data and Advanced

Calculated Data in FactoryTalk Historian DataLink for Excel XP-2003. For the Excel
2007 version, click the + sign next to Advanced to access all function options in a

single Calculated Data task pane.

Required
Arguments

Tagname or Expression
Start Time
End Time
Conversion Factor

Filter Expression

Add a filter expression to filter event values using a mathematical
expression, eliminating data for which the expression evaluates as

false. The filter expression is applied to the raw data from FactoryTalk
Historian (and not values that result from the calculation itself).
For example, the simple filter expression:
sinusoid < 70

would remove all values over 70 from the calculation. You can also
use any valid PI performance equation in the filter expression to build

more complex expressions to remove atypical peaks in data values,
for example.
Select mark as filtered to substitute

Filtered

as a placeholder for

each value or block of values filtered from the array based on the

filter

expression

(page 91).

Time Interval

Type a time interval as a

FactoryTalk Historian time

(page 86)

expression. The interval is the sampling frequency used to collect or
calculate values over the course of the time range.
For example, an interval of 15m (15 minutes) returns a value for
every 15 minute interval.

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