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OPC UA Read

Read data from OPC UA server

Since R2024a

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  • OPC UA Read Block

Libraries:
Industrial Communication Toolbox / OPC Unified Architecture

Description

The OPC UA Read block reads data from one or more nodes on an OPC Unified Architecture (UA) server. The read operation takes place synchronously at a specified sample time.

The block outputs the values of the selected nodes as a Simulink® bus signal. It optionally outputs the timestamps and the quality value associated with each node in separate outputs. The nodes that you select in the block can have different data types, which remain unchanged in the Simulink bus signal. The block outputs the timestamp as a serial date number (real-world time), or as the number of seconds from when you start simulating the model (simulation time).

Note

You need a license for both Industrial Communication Toolbox™ and Simulink software to use this block.

Note

You must connect at least one OPC UA server to use the OPC UA Read block. You can create an OPC UA client using the OPC Configuration pane in the Configuration Parameters dialog box of the model. You must add at least one OPC UA Read or OPC UA Write block in the model to enable this pane. For more information, see Configure OPC UA Client in Simulink.

Ports

Output

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The block outputs the values of the selected nodes as one of these:

  • A scalar Simulink signal when you select a single node. The signal has the same data type as the selected node.

  • A Simulink bus signal when you select multiple nodes. Each signal in the bus inherits the data type of its corresponding node. Extract the value of a node from the Simulink bus signal using a Bus Selector (Simulink) block.

For more information on the data types supported at the Value port, see OPC UA Server Data Types.

Dependencies

To enable this port, specify one or more nodes in the Nodes parameter.

Data Types: Boolean | single | double | datetime | int8 | int16 | int32 | int64 | uint8 | uint8 vector | uint16 | uint32 | uint64 | struct | char vector | bus

The block outputs the timestamp of the selected nodes data as one of these values:

  • Seconds since start (default): Represents the simulation time at which the Simulink client received data from the server.

  • Serial date number: Represents the real-world time at which the source provided data to the server.

Dependencies

To enable this port, select the Show timestamp port parameter.

Data Types: double

The block outputs the quality of read data from selected nodes as Boolean values. A logical 0 output indicates 'Bad' or 'Uncertain' quality and logical 1 indicates 'Good' quality. For details on the quality format, see OPC UA Quality.

Dependencies

To enable this port, select the Show quality port parameter.

Data Types: Boolean

Parameters

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Select the OPC UA client associated with the block.

  • To add the required clients using the OPC configuration pane, click Configure servers. For more information, see Configure OPC UA Client in Simulink.

  • To update the block to the latest OPC configuration, click Refresh.

Programmatic Use

Block Parameter: ServerList
Type: string | character vector

Select nodes to read from the specified server.

  • To add variable type nodes, click Add. This action opens the Browse Name Space dialog box for the selected OPC UA server. Using this browser, you can select the nodes that you want to add to the Nodes list.

  • To delete selected nodes, click Delete.

  • To change the order of the selected nodes in the list, click Move Up or Move Down. The serial number of the nodes determines the order in which the block outputs the signals in the bus at the Value port.

Programmatic Use

Block Parameter: NodeList
Type: string | character vector

When you select this parameter, the block outputs the quality of the read data at the Quality port, as a Boolean value. A quality value of 'good' is indicated by logical 1 and a value of either 'bad' or 'uncertain' is indicated by a logical 0.

Programmatic Use

Block Parameter: ShowQualityPort
Type: string | character vector
Values: 'on' | 'off'
Default: 'on'

When you select this parameter, the block outputs the timestamps of the selected nodes data at the Timestamp port, as a vector of doubles. You can select the timestamp basis using the Show timestamp port as parameter.

Programmatic Use

Block Parameter: ShowTimestampPort
Type: string | character vector
Values: 'on' | 'off'
Default: 'on'

Set the timestamp basis as Seconds since start or Serial date number.

Programmatic Use

Block Parameter: ShowTimestampPortAs
Type: string | character vector
Values: 'Seconds since start' | 'Serial date number'
Default: 'Seconds since start'

Define the sample time of the block in seconds. The block reads the data from the server synchronously at the specified sample time. For more information, see Specify Sample Time (Simulink).

Programmatic Use

Block Parameter: SampleTime
Type: string | character vector
Values: numeric
Default: '-1'

Version History

Introduced in R2024a

See Also

Blocks

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