Siemens SIMATIC S7-GRAPH Manual page 91

Transition
In a transition, you program conditions that control how the sequencer switches
from one step to the next.
Interlock
C
Supervision
V
I 2.3
I 2.5
A transition is displayed and programmed at the single step and single page
display levels.
The transition switches to the next step of the sequencer when the logic operation
of the conditions is satisfied, in other words when the network produces the result
1. The step following the transition becomes active.
The transition does not switch to the next step of the sequencer if the logic
operation of the conditions is not satisfied, in other words when the network
produces the result 0. The active step remains active.
Empty Transition
Transitions without programmed conditions are empty transitions. This does not
affect the execution of the sequencer. The active step is run through only once.
The following step becomes valid.
Skipping Steps
If both the transition before a step and the transition after a step are valid at the
same time, the step does not become active.
In the "Compile/Save" tab page of the "Block Settings" dialog box (menu command
Options > Block Settings), the option "Skip Steps" must be selected.
S7-GRAPH for S7-300/400 Programming Sequential Control Systems
C79000-G7076-C526-01
S1
Step1
Step1
S1 RC
V1 OFF
T1
L0 CALL
Trans1
Programming Actions and Conditions
A1.0
S_ALL
FC10
7-15