Edge 1.6.0

OPC UA: Write Node

The OPC UA: Write Node allows you to write to multiple new node values to your OPC UA Server and connected programmable logic controller (PLC). This node is only available in Edge Workflows.

OPC UA Write Node

Node Properties

There are four main parts of the properties for this node …

Connection Configuration

OPC UA Write Node Configuration

Connection Configuration contains:

  • OPC UA URI (Required): A string template for the OPC UA server URI.
  • Username (Optional): A string template for login username.
  • Password (Optional): A string template for login password.

Security Settings

You can optionally select a SSL/TLS Security Policy for the connection to the OPC UA server through the dropdown selector. Security Policy options include:

  • None
  • Basic-128
  • Basic-128 RSA-15
  • Basic-192
  • Basic-192 RSA-15
  • Basic-256
  • Basic-256 SHA-256

OPC UA Write Node SSL/TLS Security

If a Security Policy is selected, you will have the option to select between “Sign” or “Sign and Encrypt” security modes. You’ll then be required to provide a valid SSL/TLS client certificate and private key.

Write Instructions

OPC UA Write Node Write Instructions

You may define multiple write instructions for the OPC UA: Write Node, and you must define at least one. Each instruction has the following fields:

  • Namespace Index (ns): (Required) A string template or positive integer.
  • Identifier: (Required) A string template or string for the node identifier. The identifier string should begin with one of the following types:

    • i=: for unsigned integer (UINT).
    • s=: for string.
    • g=: for global unique identifier (GUID).
    • b=: for byte string.
  • Value String Template/Payload Path: (Required) The value can be a string template or from a payload path. Note: If your node value is an array you will need to provide the array values on a payload path.

Destination Path

OPC UA Write Node Result

The success or failure of each write instruction will be placed in an object at the Destination Path (a payload path) (optional) under the write key. If the write is successful the write value will be success, and conversely if the write failed the write value will be fail.

If the write failed there will be a list of errors at the Destination Path under the key errors. Because the nodes are written as a group one failed write for a node may cause the other writes to fail.

Result

The following is an example of a successful write and the Destination Path is OPCUA_PLC:

{
  "OPCUA_PLC": {
    "write": "success"
  }
}

Node Errors

The following is an example of a failure to write and the destination path is OPCUA_PLC:

{
  "OPCUA_PLC": {
    "write": "fail"
    "errors": [ { "type": "OPC-UA_WRITE_ERROR", "message": "Something useful to help you fix the issue." } ]
  }
}