Omron CX-PROGRAMMER V8.1, Руководство по эксплуатации

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ST Language Configuration
Section 5-4
5-4 ST Language Configuration
5-4-1 Statements
Statement Function Example
End of statement Ends the statement ;
Comment All text between (* and *) is treated as
a comment. (* comment *)
Assign-
ment state-
ment Assignment Substitutes the results of the expres-
sion, variable, or value on the right for
the variable on the left. A:=B;
Control
statements IF, THEN, ELSIF, ELSE,
END_IF Evaluates an expression when the
condition for it is true. IF ( condition_1 ) THEN
( expression 1 );
ELSIF ( condition_2 ) THEN
( expression 2 );
ELSE
( expression 3 );
END_IF;
CASE, ELSE, END_CASE Evaluates an express based on the
value of a variable. CASE ( variable ) OF
1: ( expression 1 );
2: ( expression 2 );
3: ( expression 3 );
ELSE
( expression 4 );
END_CASE;
FOR, TO, BY, DO,
END_FOR Repeatedly evaluates an expression
according to the initial value, final
value, and increment. FOR ( identifier ) := ( initial_value ) TO
( final_value ) BY ( increment ) DO
( expression );
END_FOR;
WHILE, DO, END_WHILE Repeatedly evaluates an expression
as long as a condition is true. WHILE ( condition ) DO
( expression);
END_WHILE;
REPEAT, UNTIL,
END_REPEAT Repeatedly evaluates an expression
until a condition is true. REPEAT
( expression);
UNTIL ( condition )
END_REPEAT;
EXIT Stops repeated processing. EXIT;
RETURN ST program:
Ends the ST task that is being exe-
cuted, and executes the next task.
ST used in SFC:
Ends the SFC action program that is
being executed, and executes the
next action program.
ST used in a function block:
Returns from the called program to
the point in the calling program
where the call occurred.
RETURN;
Function block instance call Calls a function block definition. When used in a function block:
Variable name with FUNCTION
BLOCK data type (called function
block definition’s input variable name
:= calling function block definition’s
variable name or constant, ..., called
function block definition’s output vari-
able name or constant => calling func-
tion block definition’s output variable
name, ...);