Glossary
S7-GRAPH for S7 300/400 Programming Sequential Control Systems
Glossary-4
C79000-G7076-C526-01
System checkpoint
The system checkpoint is the interface between the system and the user program.
At the system checkpoint, the signal states of the process variables can be
monitored or modified and signal states can be set at the outputs.
Transition
The transition is the part of the sequencer containing the conditions to pass control
from one step to the next.
A valid transition is a transition whose predecessor step or steps are active.
A transition that is valid and whose step enabling conditions are satisfied passes
control to the next step. The predecessor step is deactivated and the successor
step is activated.
User checkpoint
The user checkpoint is a selectable point in the user program at which signal states
of variables can be displayed.
User program
The user program includes all the blocks of the program with the instructions to be
executed.