Omron CX-PROGRAMMER V8.1, Руководство по эксплуатации

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149
Statement Descriptions
Section 5-5
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Process Flow Diagram
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Usage
Use the IF statement to perform a different operation depending on whether a
single condition (condition equation) is met.
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Description
Condition = If true, execute expression_1
Condition = If false, execute expression_2
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Precautions
• IF must be used together with END_IF.
• The condition must include a true or false equation for the evaluation
result.
Example: IF(A>10)
The
condition can also be specified as a boolean variable only rather than
an equation. As a result, the variable value is 1 (ON) = True result, 0
(OFF) = False result.
• Statements that can be used in expression_1 and expression_2 are
assignment statements, IF, CASE, FOR, WHILE, or REPEAT.
Example:
IF
< condition_1 >
THEN
IF
< condition_2 >
THEN
< expression_1 >
;
ELSE
< expression_2 >
:
END_IF;
END_IF;
The processing flow diagram is as follows:
Condition
False
True
Expression 1 Expression 2
Condition 1
Condition 2
False
True
False
True
Expression 1 Expression 1