a →transition within the →SFC network, the optional name of the transition (e.g. name_1 ) must be an →IEC-identifier Several transitions are allowed per SFC network. See the notes under "SFC elements in ST" how to create/use SFC networks efficiently and correctly.
Each transition requires the following specifications:
-
one predecessor step after the keyword FROM – example: FROM step1 In case of several predecessor steps, specify them in parenthesis and separate them from each other by: , Example: FROM (step1, step2, step3)
-
one successor step after the keyword TO – example: TO step1 In case of several successor steps, specify them in parenthesis and separate them from each other by: , Example: TO (step1, step2, step3)
-
the transition condition transition_condition; after := Use a Boolean →expression as transition condition. If this expression is evaluated with value TRUE (or an equivalent) and all predecessor steps are active, the transition is cleared (i.e., the execution is transferred from the predecessor steps to the successor steps). See "Evaluating the ST-code including the SFC networks" for information when a transition is cleard.
The usage of the transition is only possible within the current POU.
Restriction
Priorities of transitions are not evaluated.
|
|