The LADSDeviceStateMachineType state machine represents the Device’s current state. It is inspired by the AnalyserDeviceStateMachineType from the Analyzer Devices Specification.

The LADSDeviceStateMachine is depicted in Figure 15

Figure 15 – LADSDeviceStateMachine

The LADSDeviceStateMachineType is formally defined in Table 17.

Table 17 – LADSDeviceStateMachineType Definition

Attribute	Value
BrowseName	LADSDeviceStateMachineType
IsAbstract	False
References	Node Class	BrowseName	DataType	TypeDefinition	Other
Subtype of the FiniteStateMachineType defined in OPC 10000-5
0:HasComponent	Method	GotoOperate			O
0:HasComponent	Method	GotoShutdown			O
0:HasComponent	Method	GotoSleep			O
0:HasComponent	Object	Operate		StateType
0:HasComponent	Object	OperateToShutdown		TransitionType
0:HasComponent	Object	OperateToSleep		TransitionType
0:HasComponent	Object	Initialization		InitialStateType
0:HasComponent	Object	InitializationToOperate		TransitionType
0:HasComponent	Object	Shutdown		StateType
0:HasComponent	Object	Sleep		StateType
0:HasComponent	Object	SleepToOperate		TransitionType
Conformance Units
LADS LADSDeviceStateMachineType

There are four Device states, as follows:

Initialization: The Device is in its initializing sequence and cannot perform any other Task.

Operate: The Device is in Operating mode. The LADS Client uses this mode for normal operation: configuration, control, and data collection.

Sleep: The Device is still powered on and its OPC UA Server is still running, but it is not ready to perform any Tasks until it transitions to the Operate state. This state can be used to represent a PowerSave state where a Device may shut down some of its Components, such as the GUI. It can also be used to represent a Sleep state, where a Device is running with minimal services but ready to be triggered to transition into the Operate state.

Shutdown: The Device is in its power-down sequence and cannot perform any other Task. Optionally, there are devices that can be powered off via physical means, especially simpler ones. The electronics are turned off immediately; therefore, such devices do not transition into a Shutdown state.

Note: Initialization is the state in which the LADS Device waits for the completion of the power-up setup. Its sub-states are out of scope of the LADS specification.

Note: Shutdown is the state in which the LADS Device waits for the completion of the power down sequence. Its sub-states are out of scope of the LADS specification.

Children of the LADSDeviceStateMachineType have additional References, which are defined in Table 18.

Table 18 – LADSDeviceStateMachineType additional References

SourceBrowsePath	Reference Type	Is Forward	TargetBrowsePath
InitializationToOperate	0:FromState	True	Initialization
	0:ToState	True	Operate
	0:HasEffect	True	TransitionEventType
OperateToSleep	0:FromState	True	Operate
	0:ToState	True	Sleep
	0:HasCause	True	GotoSleep
	0:HasEffect	True	TransitionEventType
SleepToOperate	0:FromState	True	Sleep
	0:ToState	True	Operate
	0:HasCause	True	GotoOperate
	0:HasEffect	True	TransitionEventType
OperateToShutdown	0:FromState	True	Operate
	0:ToState	True	Shutdown
	0:HasCause	True	GotoShutdown
	0:HasEffect	True	TransitionEventType

The Component Variables of the LADSDeviceStateMachineType have additional Attributes, as defined in Table 19.

Table 19 – LADSDeviceStateMachineType Attribute Values for Child Nodes

BrowsePath	Value Attribute
Initialization 0:StateNumber	1
Operate 0:StateNumber	2
Sleep 0:StateNumber	3
Shutdown 0:StateNumber	4
SleepToOperate 0:TransitionNumber	3
OperateToShutdown 0:TransitionNumber	4
OperateToSleep 0:TransitionNumber	2
InitializationToOperate 0:TransitionNumber	1

The GotoOperate Method is used to set the Device into an operating mode. The signature of this Method is specified below. Table 20 specifies its representation in the AddressSpace.

Signature

GotoOperate ()

Table 20 – GotoOperate Method AddressSpace Definition

Attribute	Value
BrowseName	GotoOperate
References	Node Class	BrowseName	DataType	TypeDefinition	ModellingRule

The GotoShutdown Method is used to shut down the Device. The signature of this Method is specified below. Table 21 specifies its representation in the AddressSpace.

Signature

GotoShutdown ()

Table 21 – GotoShutdown Method AddressSpace Definition

Attribute	Value
BrowseName	GotoShutdown
References	Node Class	BrowseName	DataType	TypeDefinition	ModellingRule

The GotoSleep Method is used to set the Device to Sleep. The signature of this Method is specified below. Table 22 specifies its representation in the AddressSpace.

Signature

GotoSleep ()

Table 22 – GotoSleep Method AddressSpace Definition

Attribute	Value
BrowseName	GotoSleep
References	Node Class	BrowseName	DataType	TypeDefinition	ModellingRule