The OffNormalAlarmType is a specialization of the DiscreteAlarmType intended to represent a discrete Condition that is considered to be not normal. It is formally defined in Table 106. This sub type is usually used to indicate that a discrete value is in an Alarm state, it is active as long as a non-normal value is present.

Table 106 – OffNormalAlarmType definition

Attribute	Value
BrowseName	OffNormalAlarmType
IsAbstract	False
References	NodeClass	BrowseName	DataType	TypeDefinition		ModellingRule
Subtype of the DiscreteAlarmType defined in clause 5.8.24.1
HasSubtype	ObjectType	TripAlarmType	Defined in Clause 5.8.24.4
HasSubtype	ObjectType	SystemOffNormalAlarmType	Defined in Clause 5.8.24.3
HasProperty	Variable	NormalState	NodeId		PropertyType	Mandatory
ConformanceUnits
A & C OffNormal

The NormalState Property is a Property that points to a Variable which has a value that corresponds to one of the possible values of the Variable pointed to by the InputNode Property where the NormalState Property Variable value is the value that is considered to be the normal state of the Variable pointed to by the InputNode Property. When the value of the Variable referenced by the InputNode Property is not equal to the value of the NormalState Property the Alarm is Active. If this Variable is not in the AddressSpace, a NULL NodeId shall be provided.