Siemens SIMATIC S7 System Manual page 343

Example: FOR-NEXT loop
LAD
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
When I2.0 is ON, the outside
loop (Network 1 - 4) is exe-
cuted 100 times.
The inside loop (Network 2 -
3) is executed twice for each
execution of the outside loop
when I2.1 is on.
End of inside loop
End of outside loop
Program instructions
7.13 Program control
STL
Network 1
LD I2.0
FOR VW100, +1,
+100
Network 2
LD I2.1
FOR VW225, +1, +2
Network 3
NEXT
Network 4
NEXT
343