## 5.8.16.1 Overview

The ShelvedStateMachineType defines a sub-state machine that represents an advanced Alarm filtering model. This model is illustrated in Figure 16.

The state model supports two types of Shelving: OneShotShelving and TimedShelving. They are illustrated in Figure 15. The illustration includes the allowed transitions between the various sub-states. Shelving is an Operator initiated activity.

In OneShotShelving, a user requests that an Alarm be Shelved for its current Active state or if not Active its next Active state. This type of Shelving is typically used when an Alarm is continually occurring on a boundary (i.e. a Condition is jumping between High Alarm and HighHigh Alarm, always in the Active state). The OneShotShelving will automatically clear when an Alarm returns to an inactive state. Another use for this type of Shelving is for a plant area that is shutdown i.e. a long running Alarm such as a low level Alarm for a tank that is not in use. When the tank starts operation again the Shelving state will automatically clear.

In TimedShelving, a user specifies that an Alarm be shelved for a fixed time period. This type of Shelving is quite often used to block nuisance Alarms. For example, an Alarm that occurs more than 10 times in a minute may get shelved for a few minutes. The Alarm is shelved for the time period, no matter how many transitions the Alarm has between Active state and Inactive state.

In all states, the Unshelve can be called to cause a transition to the Unshelve state; this includes Un-shelving an Alarm that is in the TimedShelve state before the time has expired and the OneShotShelve state without a transition to an inactive state. In the event of a restart of an AlarmManager, the AlarmManager should recover the ShelvedStateMachine. If the system cannot determine if the state of the ShelvedStateMachine for a given alarm instance, the ShelvedStateMachine shall be set to Unshelved.

All but two transitions are caused by Method calls as illustrated in Figure 15. The “Time Expired” transition is simply a system generated transition that occurs when the time value defined as part of the “Timed Shelved Call” has expired. The “Any Transition Occurs” transition is also a system generated transition; this transition is generated when the Condition goes to an inactive state.

Figure 15 – Shelve state transitions

The ShelvedStateMachineType includes a hierarchy of sub-states. It supports all transitions between Unshelved, OneShotShelved and TimedShelved.

The state machine is illustrated in Figure 16 and formally defined in Table 71.

Figure 16 – ShelvedStateMachineType model

Table 71 – ShelvedStateMachineType definition

Attribute Value
BrowseName ShelvedStateMachineType
IsAbstract False
References NodeClass BrowseName DataType TypeDefinition ModellingRule
Subtype of the FiniteStateMachineType defined in 10000-16

HasProperty Variable UnshelveTime Duration PropertyType Mandatory

HasComponent Object Unshelved   StateType
HasComponent Object TimedShelved   StateType
HasComponent Object OneShotShelved   StateType

HasComponent Object UnshelvedToTimedShelved   TransitionType
HasComponent Object TimedShelvedToUnshelved   TransitionType
HasComponent Object TimedShelvedToOneShotShelved   TransitionType
HasComponent Object UnshelvedToOneShotShelved   TransitionType
HasComponent Object OneShotShelvedToUnshelved   TransitionType
HasComponent Object OneShotShelvedToTimedShelved   TransitionType

HasComponent Method TimedShelve Defined in Clause 5.8.16.4 Mandatory
HasComponent Method OneShotShelve Defined in Clause 5.8.16.6 Mandatory
HasComponent Method Unshelve Defined in Clause 5.8.16.2 Mandatory
HasComponent Method TimedShelve2 Defined in Clause 5.8.16.5 Optional
HasComponent Method OneShotShelve2 Defined in Clause 5.8.16.7 Optional
HasComponent Method Unshelve2 Defined in Clause 5.8.16.3 Optional

ConformanceUnits
A & C Shelving

UnshelveTime specifies the remaining time in milliseconds until the Alarm automatically transitions into the Un-shelved state. For the TimedShelved state this time is initialised with the ShelvingTime argument of the TimedShelve Method call. For the OneShotShelved state the UnshelveTime will be initialized to the Value of MaxTimeShelved Property if it is present otherwise it is initialized to the maximum Duration.

This FiniteStateMachine supports three Active states; Unshelved, TimedShelved and OneShotShelved. It also supports six transitions. The states and transitions are described in Table 72. This FiniteStateMachine also supports three Methods; TimedShelve, OneShotShelve and Unshelve.

Table 72 – ShelvedStateMachineType Additional References

SourceBrowsePath References IsForward TargetBrowsePath
UnshelvedToTimedShelved FromState True Unshelved
ToState True TimedShelved
HasEffect True AlarmConditionType
HasCause True TimedShelve
HasCause True TimedShelve2
UnshelvedToOneShotShelved FromState True Unshelved
ToState True OneShotShelved
HasEffect True AlarmConditionType
HasCause True OneShotShelve
HasCause True OneShotShelve2
TimedShelvedToUnshelved FromState True TimedShelved
ToState True Unshelved
HasEffect True AlarmConditionType
TimedShelvedToOneShotShelved FromState True TimedShelved
ToState True OneShotShelved
HasEffect True AlarmConditionType
HasCause True OneShotShelve
HasCause True OneShotShelve2
OneShotShelvedToUnshelved FromState True OneShotShelved
ToState True Unshelved
HasEffect True AlarmConditionType
OneShotShelvedToTimedShelved FromState True OneShotShelved
ToState True TimedShelved
HasEffect True AlarmConditionType
HasCause True TimedShelve
HasCause True TimedShelve2

The component Variables of the ShelvedStateMachineType have additional Attributes defined in Table 73.

Table 73 ShelvedStateMachineType Attribute values for child Nodes

BrowsePath Value Attribute
Unshelved
0:StateNumber
1
TimedShelved
0:StateNumber
2
OneShotShelved
0:StateNumber
3
UnshelvedToTimedShelved
0:TransitionNumber
12
TimedShelvedToUnshelved
0:TransitionNumber
21
TimedShelvedToOneShotShelved
0:TransitionNumber
23
UnshelvedToOneShotShelved
0:TransitionNumber
13
OneShotShelvedToUnshelved
0:TransitionNumber
31
OneShotShelvedToTimedShelved
0:TransitionNumber
32

## 5.8.16.2 Unshelve Method

The Unshelve Method sets the instance of AlarmConditionType to the Unshelved state. Normally, the MethodId found in the Shelving child of the Condition instance and the NodeId of the Shelving object as the ObjectId are passed to the Call Service. However, some Servers do not expose Condition instances in the AddressSpace. Therefore, all Servers shall also allow Clients to call the Unshelve Method by specifying ConditionId as the ObjectId where the ConditionId is the Condition that has Shelving child. The Method cannot be called with an ObjectId of the ShelvedStateMachineType Node.

Signature

Unshelve( );


Method Result Codes in Table 74 (defined in Call Service)

Table 74 – Unshelve result codes

Result Code Description
Bad_ConditionNotShelved See Table 135 for the description of this result code.

Table 75 specifies the AddressSpace representation for the Unshelve Method.

Table 75 – Unshelve Method AddressSpace definition

Attribute Value
BrowseName Unshelve
References NodeClass BrowseName DataType TypeDefinition ModellingRule
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.

## 5.8.16.3 Unshelve2 Method

The Unshelve2 Method extends the Unshelve Method, by adding an optional Comment. For other functionality see the Unshelve Method definition.

Signature

Unshelve2(
[in] LocalizedText	Comment
);


The parameters are defined in Table 76

Table 76 – Unshelve2 Method parameters

Argument Description
Comment A localized text to be applied to the Conditions.

If the Comment argument is NULL (both locale and text are empty) it will be ignored and any existing comments will remain unchanged. If the comment is to be reset, an empty text with a locale shall be provided.

Method Result Codes in Table 77 (defined in Call Service)

Table 77 – Unshelve2 result codes

Result Code Description
Bad_ConditionNotShelved See Table 135 for the description of this result code.

Table 78 specifies the AddressSpace representation for the Unshelve2 Method.

Table 78 – Unshelve2 Method AddressSpace definition

Attribute Value
BrowseName Unshelve2
References NodeClass BrowseName DataType TypeDefinition ModellingRule
HasProperty Variable InputArguments Argument[] PropertyType Mandatory
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving2

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.

## 5.8.16.4 TimedShelve Method

The TimedShelve Method sets the instance of AlarmConditionType to the TimedShelved state (parameters are defined in Table 79 and result codes are described in Table 80). Normally, the MethodId found in the Shelving child of the Condition instance and the NodeId of the Shelving object as the ObjectId are passed to the Call Service. However, some Servers do not expose Condition instances in the AddressSpace. Therefore, all Servers shall also allow Clients to call the TimedShelve Method by specifying ConditionId as the ObjectId where the ConditionId is the Condition that has the Shelving child. The Method cannot be called with an ObjectId of the ShelvedStateMachineType Node.

This Method can be called on any ConditionId, even if it is not active. The timer will start on Method invocation. The Alarm may go active and inactive multiple times during this Duration, but it will remain shelved for the Duration, unless it is changed to a different Shelving State.

Signature

TimedShelve(
[in] Duration ShelvingTime
);


The parameters are defined in Table 79

Table 79 – TimedShelve parameters

Argument Description
ShelvingTime Specifies a fixed time for which the Alarm is to be shelved. The Server may refuse the provided duration. If a MaxTimeShelved Property exist on the Alarm than the Shelving time shall be less than or equal to the value of this Property.

Method Result Codes (defined in Call Service)

Table 80 – TimedShelve result codes

Result Code Description
Bad_ConditionAlreadyShelved    See Table 135 for the description of this result code.The Alarm is already in TimedShelved state and the system does not allow a reset of the shelved timer.
Bad_ShelvingTimeOutOfRange See Table 135 for the description of this result code.

Shelving for some time is quite often used to block nuisance Alarms. For example, an Alarm that occurs more than 10 times in a minute may get shelved for a few minutes.

In some systems the length of time covered by this duration may be limited and the Server may generate an error refusing the provided duration. This limit may be exposed as the MaxTimeShelved Property.

Table 81 specifies the AddressSpace representation for the TimedShelve Method.

Table 81 – TimedShelve Method AddressSpace definition

Attribute Value
BrowseName TimedShelve
References NodeClass BrowseName DataType TypeDefinition ModellingRule
HasProperty Variable InputArguments Argument[] PropertyType Mandatory
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.

## 5.8.16.5 TimedShelve2 Method

The TimedShelve Method extends the TimedShelve Method, by adding an optional Comment. For other functionality see the TimedShelve Method definition.

Signature

TimedShelve2(
[in] Duration		ShelvingTime
[in] LocalizedText	Comment
);


The parameters are defined in Table 82.

Table 82 – TimedShelve2 parameters

Argument Description
ShelvingTime Specifies a fixed time for which the Alarm is to be shelved. The Server may refuse the provided duration. If a MaxTimeShelved Property exist on the Alarm than the Shelving time shall be less than or equal to the value of this Property.
Comment A localized text to be applied to the Condition.

Method Result Codes in Table 83 (defined in Call Service)

Table 83 – TimedShelve2 result codes

Result Code Description
Bad_ConditionAlreadyShelved    See Table 135 for the description of this result code.The Alarm is already in TimedShelved state and the system does not allow a reset of the shelved timer.
Bad_ShelvingTimeOutOfRange See Table 135 for the description of this result code.

Table 84 specifies the AddressSpace representation for the TimedShelve2 Method.

Table 84 – TimedShelve2 Method AddressSpace definition

Attribute Value
BrowseName TimedShelve2
References NodeClass BrowseName DataType TypeDefinition ModellingRule
HasProperty Variable InputArguments Argument[] PropertyType Mandatory
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving2

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.

## 5.8.16.6 OneShotShelve Method

The OneShotShelve Method sets the instance of AlarmConditionType to the OneShotShelved state. Normally, the MethodId found in the Shelving child of the Condition instance and the NodeId of the Shelving object as the ObjectId are passed to the Call Service. However, some Servers do not expose Condition instances in the AddressSpace. Therefore, all Servers shall also allow Clients to call the OneShotShelve Method by specifying ConditionId as the ObjectId where the ConditionId is the Condition that has the Shelving child. The Method cannot be called with an ObjectId of the ShelvedStateMachineType Node. This Method can be called on any ConditionId, even if it is not active.

Signature

OneShotShelve( );


Method Result Codes are defined in Table 85 (status code field is defined in Call Service)

Table 85 – OneShotShelve result codes

Result Code Description
Bad_ConditionAlreadyShelved    See Table 135 for the description of this result code.The Alarm is already in OneShotShelved state.

Table 86 specifies the AddressSpace representation for the OneShotShelve Method.

Table 86 – OneShotShelve Method AddressSpace definition

Attribute Value
BrowseName OneShotShelve
References NodeClass BrowseName DataType TypeDefinition ModellingRule
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.

## 5.8.16.7 OneShotShelve2 Method

The OneShotShelve2 Method

Signature

OneShotShelve2(
[in] LocalizedText	Comment
);


The parameters are defined in Table 87.

Table 87 – OneShotShelve2 Method parameters

Argument Description
Comment A localized text to be applied to the Conditions.

If the Comment argument is NULL (both locale and text are empty) it will be ignored and any existing comments will remain unchanged. If the comment is to be reset, an empty text with a locale shall be provided.

Method Result Codes are defined in Table 88 (status code field is defined in Call Service)

Table 88 – OneShotShelve2 result codes

Result Code Description
Bad_ConditionAlreadyShelved    See Table 135 for the description of this result code.The Alarm is already in OneShotShelved state.

Table 89 specifies the AddressSpace representation for the OneShotShelve2 Method.

Table 89 – OneShotShelve2 Method AddressSpace definition

Attribute Value
BrowseName OneShotShelve2
References NodeClass BrowseName DataType TypeDefinition ModellingRule
HasProperty Variable InputArguments Argument[] PropertyType Mandatory
AlwaysGeneratesEvent ObjectType AuditConditionShelvingEventType Defined in 5.10.7
ConformanceUnits
A & C Shelving2

If Auditing is supported, this Method shall generate an Event of AuditConditionShelvingEventType for all invocations of the Method.