Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 763)

L-force | PLC Designer
General Editors

DMS 4.1 EN 03/2011 TD29 761
RETURN instruction
The RETURN instruction can be used to leave a POU, for example depending on a
condition.
Syntax:
RETURN;
Example:
IF b=TRUE THEN
RETURN;
END_IF;
a:=a+1;
If b is TRUE, instruction a:=a+1; will not be executed, the POU will be left immediately.
IF instruction
With the IF instruction you can check a condition and, depending upon this condition,
execute instructions.
Syntax:
IF <Boolean_expression1> THEN
<IF_instructions>
{ELSIF <Boolean_expression2> THEN
<ELSIF_instructions1>
.
.
ELSIF <Boolean_expression n> THEN
<ELSIF_instructions n-1>
ELSE
<ELSE_instructions>}
END_IF;
The part in braces {} is optional.
If the <Boolean_expression1> returns TRUE, then only the <IF_Instructions> are
executed and none of the other instructions.
Otherwise the Boolean expressions, beginning with <Boolean_expression2>, are
evaluated one after the other until one of the expressions returns TRUE. Then only
those instructions after this Boolean expression and before the next ELSE or ELSIF are
evaluated.
If none of the Boolean expressions produce TRUE, then only the <ELSE_instructions>
are evaluated.