OPC UA Reader Documentation

Version: 9.0.0

Retrieved: 2025-10-09 15:16:08

OPC UA Reader

The module is used to read OpcValues from an OPC UA server on demand. When the module receives a message it will read all configured values from the OPC UA server and a message is sent from the module with the current values.

Settings

In the settings you specify the URL and credentials used for connecting to a OPC UA server. The NodeIds that are read can be loaded from a resource, by manually entering them or by providing them on the incoming message.

Name Requirements Purpose Default
Target Property string The property to write the result into. If empty the result is written to the root. Note that dot-notation is allowed to write the result into a sub-object.  
Server URL   The OPC UA server to connect to  
Disable module if no Server URL bool If true the flow will not attempt to start the module if no Server URL is configured false
Accept Untrusted Certificate   If true the server certificate will be automatically trusted by the client. true
Client Certificate   The OPC UA client certificate to use, if not set it will be autogenerated  
Security Policy None, Basic128Rsa15, Basic256, Basic256Sha256, Https Define the algorithm to use for signing and message encryption (depending on the mode specified). None
Security Mode None, Sign, SignAndEncrypt Define the mechanisms to secure the message exchange. None
Resource   The resource to import NodeIds from  
Additional NodeIds to Read   Any additional NodeIds to read apart from the ones loaded from the resource  
Include Display Name   Include display name in the output. false
Include Browse Name   Include browse name in the output. false
Keep Properties Boolean If true the incoming message will be preserved, otherwise a new message will be created false
Max Tags per Request Integer Limit number of tags to read per request to OPC server. 10000

Credential

This module contains an option to select credentials to use in the module. All credentials supported by the module are presented in a drop-down.

Input

Any message can be used to trigger a read operation, if nodeIds are configured through a resource file or listed in the Additional NodeIds to Monitor section. It is also possible to provide a list of NodeIds through the incoming message by providing a list of objects on the opcuareader.nodeids property. Each object must have a nodeId property specifying the node to read. Any additional properties will be added to the output message. In the below example we have added a name property as an example:

  "opcuareader": {
    "nodeids": [
      {
        "nodeId": "ns=2;i=4",
        "name": "test1"
      },
      {
        "nodeId": "ns=2;i=5",
        "name": "test2"
      }
    ]
  }

Output

All values for the configured NodeIds will be passed as an array to the next module(s).

Name Type Description
displayName string A localized, human readable name for the node
browserName string A non-localized, human readable name for the node
Name string Friendly name set in settings when specifying NodeIds to read
dataType string Opc Data Type
nodeId string The identifier for the node in the address space of the OPC UA server
statusCode string Status code of reading NodeId from server
sourceTimestamp string The timestamp of the source from that the value originates
value string The value/result from the OPC UA server for the specific NodeId
custom any Custom properties added through the resources will be added to each output message

Examples

Reading values from one NodeId from a OPC UA server. Note that the result will be an array.

# Settings:
Target Property=data
Server URL = opc.tcp://192.168.0.103:51210/UA/SampleServer
Resource =
Additional NodeIds to Read =
  Name = CC2001_ControlOut, Node Id = ns=5;i=29
Keep Properties = false
Security = None
IncludeDisplayName = true
IncludeBrowseName = true
MaxTagsPerRequest = 10000
Security Mode = None
Security Policy = None

# Outgoing message:
{
  "data": [
    {
      "displayName": "ControlOut",
      "browserName": "4:ControlOut",
      "name": "CC2001_ControlOut",
      "dataType": "double",
      "nodeId": "29",
      "statusCode": "good",
      "sourceTimestamp": "2018-12-21T08:14:23.6567987Z",
      "value": 0.057499999999999996
    }
  ]
}

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