UA Part 9: Alarms and Conditions - Annex F System State (Informative)

Errata exists for this version of the document.

The state of alarms is affected by the state of the process, equipment, system or plant. For example, when a tank is taken out of service, the level alarms associated with the tank would be no longer used, until the tank is returned to service. This section describes a StateMachine that can be deployed as part of a system designed and used to reflect the current state of the system, process, equipment or item. Customized version of this model can be implemented for any system, this sample is just an illustration.

The current state from the StateMachine is applied to all items in the HasNotifier hierarchy below the object with which the StateMachine is associated. The SystemState StateMachine can be used to automatically disable, enable, suppress or un-suppress Alarms related to the Object (with in the hierarchy of alarms from the given object). The StateMachine can also be used by advanced alarming software to adjust the setpoint, limits or other items related to the Alarms in the hierarchy.

Optionally, multiple SystemState StateMachines can be deployed.

Figure F.1 - SystemState transitions

F.2 SystemStateStateMachineType

The SystemStateStateMachineType includes a hierarchy of sub-states. It supports multiple transitions between Operating, StartingUp, ShuttingDown, Shutdown, OutOfService and Maintenance.

The state machine is illustrated in Figure F.2 and formally defined in Table 51.

Figure F.2 - SystemStateStateMachineType Model

Table F.1 – SystemStateStateMachineType definition

Attribute	Value
BrowseName	SystemStateStateMachineType
IsAbstract	False
References	Node Class	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the FiniteStateMachineType defined in OPC 10000-5

HasComponent	Object	Operating		StateType
HasComponent	Object	ShuttingDown		StateType
HasComponent	Object	StartingUp		StateType
HasComponent	Object	Shutdown		StateType
HasComponent	Object	OutOfService		StateType
HasComponent	Object	Maintenance		StateType

HasComponent	Object	ShutdownToOperating		TransitionType
HasComponent	Object	OperatingToShutdown		TransitionType
HasComponent	Object	ShuttingdownToShutdown		TransitionType
HasComponent	Object	OperatingToShuttingdown		TransitionType
HasComponent	Object	StartingUpToOperating		TransitionType
HasComponent	Object	ShutdownToStartingUp		TransitionType
HasComponent	Object	OutofServiceToShutdown		TransitionType
HasComponent	Object	ShutdownToOutOfService		TransitionType
HasComponent	Object	OutofServiceToOperating		TransitionType
HasComponent	Object	OperatingToOutofService		TransitionType
HasComponent	Object	MaintenanceToOutOfService		TransitionType
HasComponent	Object	OutOfServiceToMaintenance		TransitionType

HasComponent	Method	Start	Defined in Clause XXX		Optional
HasComponent	Method	Maintain	Defined in Clause XXX		Optional
HasComponent	Method	Stop	Defined in Clause XXX		Optional
HasComponent	Method	PlaceOutOfservice	Defined in Clause XXX		Optional
HasComponent	Method	QuickShutdown	Defined in Clause XXX		Optional
HasComponent	Method	QuickStart	Defined in Clause XXX		Optional
HasComponent	Method	OutOfServiceShutdown	Defined in Clause XXX		Optional

The actual selection of States and Transitions would depend on the deployment of the StateMachine. If the StateMachine were being applied to a tank or other part of a process it might have a different set of States then if it was applied to a meter or instrument. The meter may only have Operating, OutOfService and Maintenance, while the tank may have all of the described States and Transitions.

The StateMachine supports six possible states including: Operating, ShuttingDown, StartingUp, Shutdown, OutOfService, Maintenance. It supports 12 possible Transitions and 7 possible Methods.

Table F.2 - SystemStateStateMachineType transitions

BrowseName	References	BrowseName	TypeDefinition

Transitions
ShutdownToOperating	FromState	Shutdown	StateType
	ToState	Operating	StateType
	HasCause	QuickStart	Method
OperatingToShutdown	FromState	Operating	StateType
	ToState	Shutdown	StateType
	HasCause	QuickShutdown	Method
ShuttingdownToShutdown	FromState	ShuttingDown	StateType
	ToState	Shutdown	StateType
OperatingToShuttingdown	FromState	Operating	StateType
	ToState	ShuttingDown	StateType
	HasCause	Stop	Method
StartingUpToOperating	FromState	StartingUp	StateType
	ToState	Operating	StateType
ShutdownToStartingUp	FromState	Shutdown	StateType
	ToState	StartingUp	StateType
	HasCause	Start	Method
OutofServiceToShutdown	FromState	OutOfService	StateType
	ToState	Shutdown	StateType
	HasCause	OutOfServiceShutdown	Method
ShutdownToOutOfService	FromState	Shutdown	StateType
	ToState	OutOfService	StateType
	HasCause	OutOfServiceShutdown	Method
OutOfServiceToOperating	FromState	OutOfService	StateType
	ToState	Operating	StateType
	HasCause	PlaceOutOfService	Method
OperatingToOutofService	FromState	Operating	StateType
	ToState	OutOfService	StateType
	HasCause	PlaceOutOfService	Method
MaintenanceToOutofService	FromState	Maintenance	StateType
	ToState	OutOfService	StateType
	HasCause	Maintain	Method
OutOfServiceToMaintenance	FromState	OutOfService	StateType
	ToState	Maintenance	StateType
	HasCause	Maintain	Method

The system can always generate additional HasCause References, such as internal code. No HasEffect References are defined, but an implementation might define HasEffect References (such as HasEffectDisable) for disabling or enabling Alarms, suppressing Alarms or adjusting setpoints or limits of Alarms. The targets of the reference might be an individual Alarm or portion of a plant or piece of equipment. See section 7 for a list of HasEffect References that could be used.

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