Siemens SIMATIC STEP 7 V5.2 Getting Started page 8

Introduction to STEP 7
The third binary logic operation is the memory element. The SR function reacts
within a circuit diagram to certain voltage states and passes these on accordingly.
1-2
Key S
S
R
Key R
Memory Element
If key S is pressed, the bulb lights up
and remains lit until key R is pressed.
STEP 7 Getting Started
A5E00171228-01