Siemens SIMATIC S7-200 System Manual page 188

S7-200 Programmable Controller System Manual
Example: Sequence Control Relay Instruction
174
Network 1 //On the first scan enable State 1.
LD SM0.1
S S0.1, 1
Network 2 //Beginning of State 1 control region.
LSCR S0.1
Network 3 //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.
LD SM0.0
S Q0.4, 1
R Q0.5, 2
TON T37, +20
Network 4 //After a 2 second delay, transition to State 2.
LD T37
SCRT S0.2
Network 5 //End of SCR region for State 1.
SCRE
Network 6 //Beginning of State 2 control region.
LSCR S0.2
Network 7 //Control the signals for Street 2:
//1. Set: Turn on the green light.
//2. Start a 25- -second timer.
LD SM0.0
S Q0.2, 1
TON T38, +250
Network 8 //After a 25 second delay, transition to State 3.
LD T38
SCRT S0.3
Network 9 //End of SCR region for State 2.
SCRE