UA Part 9: Alarms and Conditions - 5.8.19 Exclusive Limit Types

This clause describes the state machine and the base AlarmType behaviour for AlarmConditionTypeswith multiple mutually exclusive limits.

5.8.19.2 ExclusiveLimitStateMachineType

The ExclusiveLimitStateMachineTypedefines the state machine used by AlarmConditionTypesthat handle multiple mutually exclusive limits. It is illustrated in Figure 19.

Figure 19– ExclusiveLimitStateMachineType

It is created by extending the FiniteStateMachineType. It is formally defined in Table 93and the state transitions are described in Table 94.

Table 93– ExclusiveLimitStateMachineType definition

Attribute	Value
BrowseName	ExclusiveLimitStateMachineType
IsAbstract	False
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the FiniteStateMachineType
HasComponent	Object	HighHigh		StateType
HasComponent	Object	High		StateType
HasComponent	Object	Low		StateType
HasComponent	Object	LowLow		StateType
HasComponent	Object	LowToLowLow		TransitionType
HasComponent	Object	LowLowToLow		TransitionType
HasComponent	Object	HighToHighHigh		TransitionType
HasComponent	Object	HighHighToHigh		TransitionType
ConformanceUnits
A & C Exclusive Limit

Table 94– ExclusiveLimitStateMachineType Additional References

SourceBrowsePath	References	IsForward	TargetBrowsePath
HighHighToHigh	FromState	True	HighHigh
	ToState	True	High
	HasEffect	True	AlarmConditionType
HighToHighHigh	FromState	True	High
	ToState	True	HighHigh
	HasEffect	True	AlarmConditionType
LowLowToLow	FromState	True	LowLow
	ToState	True	Low
	HasEffect	True	AlarmConditionType
LowToLowLow	FromState	True	Low
	ToState	True	LowLow
	HasEffect	True	AlarmConditionType

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The component Variablesof the ExclusiveLimitStateMachineTypehave additional Attributesdefined in Table 95.

Table 95– ExclusiveLimitStateMachineType Attribute values for child Nodes

BrowsePath

Value Attribute

HighHigh

0:StateNumber

High

0:StateNumber

Low

0:StateNumber

LowLow

0:StateNumber

LowToLowLow

0:TransitionNumber

LowLowToLow

0:TransitionNumber

HighToHighHigh

0:TransitionNumber

HighHighToHigh

0:TransitionNumber

The ExclusiveLimitStateMachineTypedefines the sub state machine that represents the actual level of a multilevel Alarm when it is in the Activestate. The sub state machine defined here includes High, Low, HighHighand LowLowstates. This model also includes in its transition state a series of transition to and from a parent state, the inactive state. This state machine as it is defined shall be used as a sub state machine for a state machine which has an Activestate. This Activestate could be part of a “level” Alarmor “deviation” Alarmor any other Alarmstate machine.

The LowLow, Low, High, HighHighare typical for many industries. Vendors can introduce sub-state models that include additional limits; they may also omit limits in an instance. If a model omits states or transitions in the StateMachine, it is recommended that they provide the optional Property AvailableStatesand/or AvailableTransitions(see 10000-16).

5.8.19.3 ExclusiveLimitAlarmType

The ExclusiveLimitAlarmTypeis used to specify the common behaviour for Alarm Typeswith multiple mutually exclusive limits. The ExclusiveLimitAlarmTypeis illustrated in Figure 20.

Figure 20– ExclusiveLimitAlarmType

The ExclusiveLimitAlarmTypeis formally defined in Table 96.

Table 96– ExclusiveLimitAlarmType definition

Attribute	Value
BrowseName	ExclusiveLimitAlarmType
IsAbstract	False
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the LimitAlarmType defined in clause 5.8.18.
HasSubtype	ObjectType	ExclusiveLevelAlarmType	Defined in Clause 5.8.21.3
HasSubtype	ObjectType	ExclusiveDeviationAlarmType	Defined in Clause 5.8.22.3
HasSubtype	ObjectType	ExclusiveRateOfChangeAlarmType	Defined in Clause 5.8.23.3
HasComponent	Object	LimitState		ExclusiveLimitStateMachineType	Mandatory
ConformanceUnits
A & C Exclusive Limit

The LimitStateis a sub state of the ActiveState and has an IsTrueSubStateOfreference to the ActiveState. The LimitStaterepresents the actual limit that is violated in an instance of ExclusiveLimitAlarmType. When the ActiveStateof the AlarmConditionTypeis inactive the LimitStateshall not be available and shall return NULL on read. Any Eventsthat subscribe for fields from the LimitStatewhen the ActiveStateis inactive shall return a NULL for these unavailable fields.