7.8.9
SCL program control statements
7.8.9.1
Overview of SCL program control statements
Structured Control Language (SCL) provides three types of program control statements for
structuring your user program:
● Selective statements: A selective statement enables you to direct program execution into
● Loops: You can control loop execution using iteration statements. An iteration statement
● Program jumps: A program jump means an immediate jump to a specified jump
These program control statements use the syntax of the PASCAL programming language.
Table 7- 113 Types of SCL program control statements
Program control statement
Selective
IF-THEN statement
(Page 268)
CASE statement
(Page 269)
Loop
FOR statement
(Page 270)
WHILE-DO statement
(Page 271)
REPEAT-UNTIL
statement (Page 272)
Program jump
CONTINUE statement
(Page 273)
EXIT statement
(Page 273)
GOTO statement
(Page 274)
RETURN statement
(Page 274)
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
alternative sequences of statements.
specifies which parts of a program should be iterated depending on certain conditions.
destination and therefore to a different statement within the same block.
Description
Enables you to direct program execution into one of two alternative
branches, depending on a condition being TRUE or FALSE
Enables the selective execution into 1 of
on the value of a variable
Repeats a sequence of statements for as long as the control variable
remains within the specified value range
Repeats a sequence of statements while an execution condition
continues to be satisfied
Repeats a sequence of statements until a terminate condition is met
Stops the execution of the current loop iteration
Exits a loop at any point regardless of whether the terminate condition
is satisfied or not
Causes the program to jump immediately to a specified label
Causes the program to exit the block currently being executed and to
return to the calling block
Basic instructions
7.8 Program control operations
n
alternative branches, based
267