Rockwell-automation 9301 Series RSView32 Users Guide Uživatelský manuál stáhnout pdf (Strana 538)

Creating expressions  14–25

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.

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. Keep in mind that the

statement is a mathematical equation and true means a non–zero value,

and false means zero.

The if–then–else structure is illustrated below.

Nested if–then–else structure

It is common to nest an if–then–else structure inside the ‘then’ or

‘else’ part of an if–then–else structure.

value2 value1

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Rockwell-automation 9301 Series RSView32 Users Guide Uživatelský manuál Strana 538