6.8.4 Valve Move Method

Move Method is used to open or close a valve.

Signature 

	Move (
			[in] CommandEnum		Direction,
			[in] 0:Boolean		OverrideInterlock,
			[in] SEMEnum			SEM,
			[in] 0:Boolean		Signature,
			[in] 0:Boolean		ShutdownRequest);
Table 54 – Move Arguments (Valve)
Argument Description
DirectionThe enumeration indicates whether the command is to open the valve or to close the valve
OverrideInterlockBoolean indicating if the open or close command should override any defeatable interlocks
SEMThe enumeration indicates which SEM to send the command to.
SignatureBoolean indicating if a profile /signature should be generated by this move command request. If the optional Variable SignatureRequestStatus is not provided on the Object, this parameter is ignored by the Server.
ShutdownRequestBoolean indicates that this command is part of a shutdown sequence. It should be noted that the responsibility for the shutdown is on the DCS and operator side. All non defeatable interlocks of the subsea system will be overridden which can cause damage to the subsea system.

Method result codes are defined as part of the Call Service (see OPC 10000-4). They are described in Table 124 for ease of reference.

Comments:

The Move Method initiates a move operation. Parameters include opening or closing of the valve, overriding of any interlocks, the SEM selection to use for the command, if a profile / signature is being requested for this move operation or if a shutdown is being requested. The Method will complete when the command has been accepted. If the command has not been accepted by the Server, then the Method returns an error indicating the operation could not be performed. In the case when the Move command is accepted by the Server, the move operation may or may not be complete at the time the Method returns to the Client. Therefore, the Client must monitor the Position of the valve to determine when the Move command actually finishes.

The OverrideInterlocks, SEM, Signature and Shutdown are optional parameters, but OPC UA Methods do not allow for optional parameters. These parameters must always be provided. On a Server basis the parameter may be configured to not be utilised. If a Server is configured to not utilise a parameter, this is because the functionality is not required.

Table 55 specifies the AddressSpace representation for the Move Method.

Table 55 – Move Method AddressSpace Definition (Valve)
Attribute Value
BrowseNameMove
References Node Class BrowseName DataType TypeDefinition Other
0:HasProperty Variable 0:InputArguments0:Argument[] 0:PropertyTypeM
ConformanceUnits
MDIS Valve Base