opcuanode

Create OPC UA node objects

Syntax

nodeList = opcuanode(index,id)

nodeList = opcuanode(index,id,uaClient)

Description

nodeList = opcuanode(index,id) creates an OPC UA node object or array of objects from the information in index and id. index is a number or numeric vector. id is a character vector, string, scalar integer, or cell array containing character vectors and scalar integers. Use this syntax to create node objects for known nodes on an OPC UA server. Each node Name property is set to 'Index:Identifier', and other properties of the node are left empty until you use the node to access an OPC UA server. When you successfully use the node object with a client using writeValue or readValue, the Client property of the node is set to the client, and other attributes are read from that client.

nodeList = opcuanode(index,id,uaClient) immediately associates the node object with the specified client uaClient. If uaClient is connected at this time, the opcuanode function also retrieves other properties from the server associated with uaClient.

Use opcuanode to create node objects only when you know the index and identifier of nodes you are interested in. For nodes that you need to find from the server, create node objects by browsing the namespace of a connected OPC UA client object with browseNamespace or getNamespace, or browse the Parent and Children properties of existing node objects.

Examples

Create Node and Write to Server

Construct a node object from index and identifier values. Use the node to write a value to the server, then note that the node has its properties set from the server.

s = opcuaserverinfo("localhost");
uaClient = opcua(s);
connect(uaClient);
myNode = opcuanode(2,10225); % Not associated with server yet.
writeValue(uaClient,myNode,pi)
myNode

myNode = 
OPC UA Node:
   Node Information:
                      Name: '2:10225'
               Description: ''
            NamespaceIndex: 2
                Identifier: 10225
                  NodeType: 'Variable'

   Hierarchy Information:
                    Parent: ''
                  Children: 0

   Variable Information:
            ServerDataType: 'Float'
        AccessLevelCurrent: 'read/write'
        AccessLevelHistory: 'none'
               Historizing: 0

Create Node and Browse Other Nodes

Create a known node object and use it to browse for other nodes.

uaClient = opcua("localhost",51210);
connect(uaClient);
boilerNode = opcuanode(4,1241,uaClient);
ftxNodes = findNodeByName(boilerNode,'FTX','-partial')

ftxNodes = 
1x2 OPC UA Node array:
    index   Name   NsInd  Identifier  NodeType  Children
    -----  ------  -----  ----------  --------  --------
      1    FTX001  4      1243        Object    1
      2    FTX002  4      1266        Object    1

Input Arguments

index — Node index

numeric value

Node index, specified as a numeric value or array.

Example: 2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

id — Node ID

numeric | char | string

Node ID, specified as a numeric, character, or string value, or an array of these.

Example: 10225

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | char | string

uaClient — OPC UA client

opc.ua.Client object

OPC UA client, specified as an opc.ua.Client object. You can create the client using the opcua function.

Example: opcua()

Output Arguments

nodeList — OPC UA nodes

opc.ua.Node objects

OPC UA nodes, returned as an array of opc.ua.Node objects. An OPC UA node object stores information about a node in an OPC UA server. You can read and write current data, and read historical data using variable nodes. You can browse the namespace using object and variable nodes.

A node’s type is described by its NodeType property, which can indicate an 'Object' or 'Method' or 'Variable' type. Variable type nodes can contain data values, while object type nodes cannot contain values. Method nodes can have input and output arguments. Each node type can contain other nodes: object nodes can contain object, method and variable nodes, variable nodes can contain other variable nodes.

Node objects include these properties.

Property	Description
Node Information
Name	Display name for the node.
Description	Character vector describing the node.
NamespaceIndex	Namespace index for the node.
Identifier	Unique identifier with data type as a character vector or integer.
NodeType	Type of node: 'Object', 'Method', or 'Variable'.
Hierarchy Information
Parent	Parent node of the node.
Children	Child nodes of the node.
Variable Information
ServerDataType	OPC UA data type for node.
AccessLevelCurrent	User access level to current value: 'none', 'read', 'write', 'read/write'.
AccessLevelHistory	User access level to historical values: 'none', 'read', 'write', 'read/write'.
Historizing	True if the server is storing history for the node data.
Method Information
Executable	True if the node is executable.
UserExecutable	True if the node is executable by the current user.
NumInputs	Number of inputs required by the node.
InputTypes	Data types of input arguments.
NumOutputs	Number of outputs returned by the node.
OutputTypes	Data types of output arguments.

Version History

Introduced in R2015b