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5.8 Alarm model ToC Previous Next

5.8.18 Exclusive Limit Types ToC Previous Next

5.8.18.1 Overview ToC

This clause describes the state machine and the base Alarm Type behaviour for AlarmConditionTypes with multiple mutually exclusive limits.

5.8.18.2 ExclusiveLimitStateMachineType ToC Model

The ExclusiveLimitStateMachineType defines the state machine used by AlarmConditionTypes that handle multiple mutually exclusive limits. It is illustrated in Figure 18.

readme_files/image021.png Figure 18 – ExclusiveLimitStateMachineType

It is created by extending the FiniteStateMachineType. It is formally defined in Table 91 and the state transitions are described in Table 92.

Table 91 – ExclusiveLimitStateMachineType definition

Attribute Value
BrowseName ExclusiveLimitStateMachineType
IsAbstract False

Subtype of the FiniteStateMachineType

References NodeClass BrowseName DataType TypeDefinition ModellingRule
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 92 – 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

The component Variables of the ExclusiveLimitStateMachineType have additional Attributes defined in Table 93.

Table 93 ExclusiveLimitStateMachineType Attribute values for child Nodes

BrowsePath Value Attribute
   HighHigh
   0:StateNumber
1
   High
   0:StateNumber
2
   Low
   0:StateNumber
3
   LowLow
   0:StateNumber
4
   LowToLowLow
   0:TransitionNumber
34
   LowLowToLow
   0:TransitionNumber
43
   HighToHighHigh
   0:TransitionNumber
21
   HighHighToHigh
   0:TransitionNumber
12

The ExclusiveLimitStateMachineType defines the sub state machine that represents the actual level of a multilevel Alarm when it is in the Active state. The sub state machine defined here includes High, Low, HighHigh and LowLow states. 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 Active state. This Active state could be part of a “level” Alarm or “deviation” Alarm or any other Alarm state machine.

The LowLow, Low, High, HighHigh are 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 AvailableStates and/or AvailableTransitions (see 10000-5).

5.8.18.3 ExclusiveLimitAlarmType ToC Model

The ExclusiveLimitAlarmType is used to specify the common behaviour for Alarm Types with multiple mutually exclusive limits. The ExclusiveLimitAlarmType is illustrated in Figure 19.

readme_files/image022.png Figure 19 – ExclusiveLimitAlarmType

The ExclusiveLimitAlarmType is formally defined in Table 94.

Table 94 – ExclusiveLimitAlarmType definition

Attribute Value
BrowseName ExclusiveLimitAlarmType
IsAbstract False

Subtype of the LimitAlarmType defined in clause 5.8.17.

References NodeClass BrowseName DataType TypeDefinition Modelling Rule
HasSubtype ObjectType ExclusiveLevelAlarmType Defined in Clause 5.8.20.3    
HasSubtype ObjectType ExclusiveDeviationAlarmType Defined in Clause 5.8.21.3    
HasSubtype ObjectType ExclusiveRateOfChangeAlarmType Defined in Clause 5.8.22.3    
HasComponent Object LimitState   ExclusiveLimitStateMachineType Mandatory
ConformanceUnits          
A & C Exclusive Limit          

The LimitState is a sub state of the ActiveState and has an IsTrueSubStateOf reference to the ActiveState. The LimitState represents the actual limit that is violated in an instance of ExclusiveLimitAlarmType. When the ActiveState of the AlarmConditionType is inactive the LimitState shall not be available and shall return NULL on read. Any Events that subscribe for fields from the LimitState when the ActiveState is inactive shall return a NULL for these unavailable fields.

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