This VariableTypedefines the general characteristics of a DiscreteItemthat can have two states. The TwoStateDiscreteTypederives from the DiscreteItemType. It is formally defined in Table 4.
Table 4– TwoStateDiscreteType definition
Attribute |
Value |
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BrowseName |
TwoStateDiscreteType |
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IsAbstract |
False |
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ValueRank |
−2 (−2 = ‘Any’) |
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DataType |
Boolean |
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References |
NodeClass |
BrowseName |
DataType |
TypeDefinition |
ModellingRule |
Subtype of the DiscreteItemTypedefined in 5.3.3; i.e the Propertiesof that type are inherited. |
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HasProperty |
Variable |
TrueState |
LocalizedText |
PropertyType |
Mandatory |
HasProperty |
Variable |
FalseState |
LocalizedText |
PropertyType |
Mandatory |
TrueStatecontains a string to be associated with this DataItemwhen it is TRUE. This is typically used for a contact when it is in the closed (non-zero) state.
for example: "RUN", "CLOSE", "ENABLE", "SAFE“, etc.
FalseStatecontains a string to be associated with this DataItemwhen it is FALSE. This is typically used for a contact when it is in the open (zero) state.
for example: "STOP", "OPEN", "DISABLE", "UNSAFE“, etc.
If the item contains an array, then the Propertieswill apply to all elements in the array.
The StatusCode SemanticsChangedbit shall be set if any of the FalseState or TrueState (changes can cause misinterpretation by users or (scripting) programs) Propertiesare changed (see section 5.2for additional information).