WOLFRAM SYSTEM MODELER

TriggeredRead

A block for reading data from an OPC server at intervals determined by an external Boolean signal (trigger)

Wolfram Language

In[1]:=
SystemModel["OPCUA.Blocks.SamplerInteger.TriggeredRead"]
Out[1]:=

Information

This block reads data of scalar type Integer from the OPC UA server it is connected to. Unlike the read blocks that have a parameter for setting the sample period, the triggered read blocks read data when Boolean input signal trigger has a rising edge. The block inherits the properties of the partial model TriggeredSampler. Only scalar nodes can be read; i.e. no array or matrix nodes are supported.

At every sampling instant, external function readExternalInteger is called from within the block.

Relevant Parameters

  • nodeID: which OPC UA node to read data from (ID value should always be inside quotes)
  • nodeNamespace: which namespace the node is located in
  • nodeIDType: which ID type to use, numeric or string

Interfaces

  • y: an Integer output, which is the sampled signal
  • serverID: the connector that connects the block to the OPC server component
  • trigger: a Boolean input that determines when the block should sample data

Parameters (4)

nodeIDType

Value:

Type: UANodeIdType

Description: The node identifier type

nodeID

Value:

Type: String

Description: The node identifier

nodeNamespace

Value:

Type: Integer

Description: The node namespace

y_start

Value:

Type: Integer

Description: Initial value of output signal

Connectors (3)

trigger

Type: BooleanInput

Description: Boolean input that determines when sampling should occur

serverID

Type: BlockConnector

Description: The unique ID of the server the block is connected to

y

Type: IntegerOutput

Description: The data read from the item on the OPC server

Used in Examples (1)

TriggeredReadAndWrite

OPCUA.Examples

Basic example that demonstrates how to write to and read from nodes on an OPC UA server using a signal trigger