Rockwell Automation FactoryTalk Historian SE DataLink 4.2 User Guide - Manual (Page 109)

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FactoryTalk Historian Expression Examples
These examples use the tag delimiters : (colon) and . (period). Your
FactoryTalk Historian system may use different delimiters.
The following expression determines the sum of the value of sinusoid
cubed and the value of cdf144 divided by 10:
(('sinusoid')^3 + 'cdf144'/10)
The expression below evaluates to true (non-zero) if the absolute value of
the tag mytag is at least 14.65.
(abs('my:tag') >= 14.65)
When comparing digital tags, use the negative of the digital state code
number. For digital tags, use the digital state string itself. For example:
('my:tag' = "Manual")
The following expression evaluates to True if the value of the tag sinusoid
is less than 45 and the square root of the value of the tag vdf1002 is
greater than 2:
('sinusoid' < 45 and sqr('vd:f1002') > 2)
Manual Function Entry
FactoryTalk Historian DataLink provides tools that can be used to build
any FactoryTalk Historian DataLink function graphically. Experienced
users of Excel and FactoryTalk Historian may prefer to enter functions
directly in the Excel formula bar.
The following topics apply to FactoryTalk Historian DataLink functions
when entered directly in this manner.