Transitions in ST
(* transition with one predecessor step and one successor step *)
TRANSITION (* optional_begin *) name_1 (* optional_end *) FROM step_name_1 TO step_name_2
:= transition_condition;
END_TRANSITION
(* transition with several predecessor steps and several successor steps *)
TRANSITION (* optional_begin *) name_2 (* optional_end *) FROM (step_name_1, step_name_2, ...) TO (step_name_3, step_name_4, ...)
:= transition_condition;
END_TRANSITION
Meaning |
a →transition within the →SFC network, the optional name of the transition (e.g. name_1) must be an →IEC-identifier Each transition requires the following specifications:
The usage of the transition is only possible within the current POU. Restriction Priorities of transitions are not evaluated. |
(* The transition 't0' is connected with the predecessor step 'step0' and the successor steps 'step1' and 'step2'. *)
(* Its transitions condition: cntStep0 MOD 10 = 0 *)
TRANSITION t0 FROM step0 TO (step1,step2)
:= cntStep0 MOD 10 = 0;
END_TRANSITION
(* The transition 't1' is connected with the predecessor steps 'step1' and 'step2' and with the successor step 'step0'. *)
(* Its transitions condition: MyFun01(In:=Var1) -- condition for this: 'MyFun01' has a Boolean return value. *)
TRANSITION t1 FROM (step1,step2) TO step0
:= MyFun01(In:=Var1);
END_TRANSITION