Siemens Simatic S7 Series System Manual

Program instructions
7.13 Program control
S7-200 SMART
308 System Manual, 09/2015, A5E03822230-AC
LAD
STL
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.

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.