
14–1
Chapter
14 Creating expressions
This chapter includes:
instructions for creating expressions
description of the components used for building expressions
About expressions
Sometimes the data you gather from devices is only meaningful when
you:
compare it to other values
combine it with other values
create a cause–effect relationship with other values
Expressions allow you to create mathematical or logical combinations
of data that return more meaningful values.
Expression components
Expressions can be built from:
tag values
constants
mathematical, relational, logical, and bitwise operators
built–in functions
if–then–else
logic
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