Move Method is used to open or close a valve.

Method Declaration:

Move(

[in] Direction CommandEnum,

[in] OverrideInterlocks Boolean,

[in] SEM SEMEnum,

[in] Signature Boolean,

[in] ShutdownRequest Boolean

);

Table 29 - Move Arguments

Argument

Description

Direction

The enumeration indicates whether the command is to open the valve or to close the valve

OverrideInterlocks

Boolean indicating if the open or close command should override any defeatable interlocks

SEM

The enumeration indicates which SEM to send the command to.

Signature

Boolean 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.

ShutdownRequest

Boolean indicates that this command is part of a shutdown sequence.

Method result codes are defined as part of the Call Service (see OPC UA Services Part 4 – Services specification). They are described in Table 94 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 30 specifies the AddressSpace representation for the Move Method.

Table 30 - Move Method AddressSpace Definition

Attribute

Value

BrowseName

Move

References

Node Class

BrowseName

DataType

TypeDefinition

ModellingRule

HasProperty

Variable

InputArguments

Argument[]

PropertyType

Mandatory