Siemens Simatic S7 Series System Manual

Program instructions
7.13 Program control
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
307
Example: SCR sequential control flow
In the following sample program, the first scan bit SM0.1, is used to set S0.1, which will be
the active State 1 on the first scan. After a 2-second delay, T37 causes a transition to State
2. This transition deactivates the State 1 SCR (S0.1) segment and activates the State 2 SCR
(S0.2) segment.
LAD
STL
On the first scan enable state 1.
Network 1
LD SM0.1
S S0.1, 1
Beginning of state 1 control
region.
Network 2
LSCR S0.1
Control the signals for street 1:
1. Set: Turn on the red light.
2. Reset: Turn off the yellow
and green lights.
3. Start a 2-second timer.
Network 3
LD SM0.0
S Q0.4, 1
R Q0.5, 2
TON T37, +20
After a 2 second delay, transi-
tion to state 2.
Network 4
LD T37
SCRT S0.2
End of SCR region for state 1.
Network 5
SCRE
Beginning of state 2 control
region.
Network 6
LSCR S0.2
Control the signals for street 2:
1. Set: Turn on the green light.
2. Start a 25-second timer.
Network 7
LD SM0.0
S Q0.2, 1
TON T38, +250
After a 25 second delay, transi-
tion to state 3.
Network 8
LD T38
SCRT S0.3

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.