Siemens SIMATIC S7 - Page 350

Program instructions
7.13 Program control
S7-200 SMART
350 System Manual, V2.3, 07/2017, A5E03822230-AF
LAD
STL
After a 25 second delay, transi-
tion to state 3.
Network 8
LD T38
SCRT S0.3
End of SCR region for state 2.
Network 9
SCRE
Sequential control flow
A process with a well-defined sequence of steps is easy to model with SCR segments. For
example, consider a cyclical process, with 3 steps, that should return to the first step when
the third has completed.
Divergent control flow
In many applications, a single stream of sequential states must be split into two or more
different streams. When a control stream diverges into multiple streams, all outgoing streams
must be activated simultaneously.