The TransitionVariableType is the base VariableType for Variables that store a Transition that occurred within a StateMachine as a human readable name.
The SourceTimestamp for the value specifies when the Transition occurred. This value may also be exposed with the TransitionTime Property.
The TransitionVariableType is formally defined in Table 3.
Table 3 – TransitionVariableType definition
|ValueRank||−1 (−1 = Scalar)|
|References||Node Class||BrowseName||DataType||TypeDefinition||Modelling Rule|
|Subtype of the BaseDataVariableType defined in OPC 10000-5Note that a Reference to this subtype is not shown in the definition of the BaseDataVariableType.|
|HasSubtype||VariableType||FiniteTransitionVariableType||Defined in 4.4.7|
|Base Info State Machine Instance|
Id is a name which uniquely identifies a Transition within the StateMachineType. A subtype may restrict the DataType.
Name is a QualifiedName which uniquely identifies a transition within the StateMachineType.
Number is an integer which uniquely identifies a transition within the StateMachineType.
TransitionTime specifies when the transition occurred.
EffectiveTransitionTime specifies the time when the current state or one of its substates was entered. If, for example, a StateA is active and – while active – switches several times between its substates SubA and SubB, then the TransitionTime stays at the point in time where StateA became active whereas the EffectiveTransitionTime changes with each change of a substate.