Using if -then-else logic in expressions, Using if-then-else logic in expressions – 19, Using if-then-else logic in expressions – Rockwell Automation FactoryTalk View Site Edition Users Guide User Manual
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To examine multiple alarms at once (a set of alarms for a machine in a particular area, for
example) use a wildcard character in the expression argument.
For more information about using FactoryTalk alarm functions in expressions, and for
examples, see Chapter 12, Setting up FactoryTalk alarms.
About using FactoryTalk alarm names in expressions
To supply a FactoryTalk alarm name for an expression, type it in the Expressions box, or
click the Alarms button to browse for and select one or more tags in the Alarm Source
browser.
You must specify an alarm source when you use the built-in FactoryTalk alarm functions
in an expression. An alarm source might be a single alarm, or an area containing several
alarms.
When referring to an alarm source, you can use an absolute or relative reference.
Enclose alarm names that contain dashes or start with a number in brackets {} when you
use them in an expression. Also use brackets when using wildcard characters (* or ?) to
represent multiple alarms.
You can also use tag placeholders in alarm names, to substitute values for the placeholders
at run time. For more information about tag placeholders, see page 16-35.
Using if-then-else logic in expressions
Use if-then-else logic in an expression to carry out an action conditionally, or to branch
actions depending on the statements in the expression. You can also use if-then-else
statements to repeat actions until a condition changes.
To build conditional expressions, use the relational operators and the logical operators for
the statement, and values.
The if-then-else structure is:
If statement Then value1 Else value2
This wildcard character
Does this
?
Matches any single character.
*
Matches any number of characters, including the
backslash (\) character.
Do not confuse the if-then-else expression with the If command. For details about the If
command, see the FactoryTalk View Site Edition Help.