The ShelvedStateMachineType defines a sub-state machine that represents an advanced Alarm filtering model. This model is illustrated in Figure 17.

The state model supports two types of Shelving: OneShotShelving and TimedShelving. They are illustrated in Figure 16. 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 16. 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.

image019.png

Figure 16 – 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 17 and formally defined in Table 73.

image020.png

Figure 17 – ShelvedStateMachineType model

Table 73 – 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 5.8.17.4

Mandatory

HasComponent

Method

OneShotShelve

Defined in Clause 5.8.17.6

Mandatory

HasComponent

Method

Unshelve

Defined in Clause 5.8.17.2

Mandatory

HasComponent

Method

TimedShelve2

Defined in Clause 5.8.17.5

Optional

HasComponent

Method

OneShotShelve2

Defined in Clause 5.8.17.7

Optional

HasComponent

Method

Unshelve2

Defined in Clause 5.8.17.3

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 74. This FiniteStateMachine also supports three Methods; TimedShelve, OneShotShelve and Unshelve.

Table 74 – 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 75.

Table 75 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

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 76 (defined in Call Service)

Table 76 – Unshelve result codes

Result Code

Description

Bad_ConditionNotShelved

See Table 137 for the description of this result code.

Table 77 specifies the AddressSpace representation for the Unshelve Method.

Table 77 – 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.

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

Signature

Unshelve2(

[in] LocalizedTextComment

);

The parameters are defined in Table 78

Table 78 – 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 79 (defined in Call Service)

Table 79 – Unshelve2 result codes

Result Code

Description

Bad_ConditionNotShelved

See Table 137 for the description of this result code.

Table 80 specifies the AddressSpace representation for the Unshelve2 Method.

Table 80 – 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.

The TimedShelve Method sets the instance of AlarmConditionType to the TimedShelved state (parameters are defined in Table 81 and result codes are described in Table 82). 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 81

Table 81 – 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 82 – TimedShelve result codes

Result Code

Description

Bad_ConditionAlreadyShelved

See Table 137 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 137 for the description of this result code.

Comments

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 83 specifies the AddressSpace representation for the TimedShelve Method.

Table 83 – 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.

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] LocalizedTextComment

);

The parameters are defined in Table 84.

Table 84 – 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 85 (defined in Call Service)

Table 85 – TimedShelve2 result codes

Result Code

Description

Bad_ConditionAlreadyShelved

See Table 137 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 137 for the description of this result code.

Table 86 specifies the AddressSpace representation for the TimedShelve2 Method.

Table 86 – 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.

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 87 (status code field is defined in Call Serv ice)

Table 87 – OneShotShelve result codes

Result Code

Description

Bad_ConditionAlreadyShelved

See Table 137 for the description of this result code.

The Alarm is already in OneShotShelved state.

Table 88 specifies the AddressSpace representation for the OneShotShelve Method.

Table 88 – 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.

The OneShotShelve2 Method

Signature

OneShotShelve2(

[in] LocalizedTextComment

);

The parameters are defined in Table 89.

Table 89 – 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 90 (status code field is defined in Call Serv ice)

Table 90 – OneShotShelve2 result codes

Result Code

Description

Bad_ConditionAlreadyShelved

See Table 137 for the description of this result code.

The Alarm is already in OneShotShelved state.

Table 91 specifies the AddressSpace representation for the OneShotShelve2 Method.

Table 91 – 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.