Rockwell-automation FactoryTalk View Machine Edition Users Guide Manual do Utilizador Página 494

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FACTORYTALK VIEW MACHINE EDITION USERS GUIDE
23-16
• • • • •
If-then-else
If-then-else expressions carry out an action conditionally or branch actions depending on
the statements in the expression. The if-then-else statements enable the expression to
perform different actions in different situations and to repeat activities 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
If the statement is true then the expression returns value1; if the statement is false then the
expression returns value2. If the result of the statement is a non-zero value, the statement
is true (and returns value1); if the result is 0, the statement is false (and returns value2).
The if-then-else structure is illustrated here.
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