node-red opcua

### Node-RED OPC UA Integration and Configuration Guide

For integrating OPC UA with Node-RED, the `node-red-contrib-opcua` package is essential as it provides nodes specifically designed to interact with OPC UA servers[^1]. Installation of this package can be done through the palette manager within Node-RED or via npm command line tool.

#### Installing node-red-contrib-opcua Package
To install using npm on a terminal connected to where Node-RED resides:

npm install node-red-contrib-opcua

After installation completes successfully, restart Node-RED service so that new components become available inside flows editor interface.

#### Configuring OPC-UA Nodes Within Flows Editor Interface
Once installed properly, several types of OPC-UA related nodes appear under categories like "input", "output". These include but are not limited to opcua-client-in/opcuaclient-out which allow reading from/writing into specific tags present at remote endpoints exposed by an external system implementing such protocol standards.

When configuring these elements visually within flow diagrams provided by platform's web-based UI, ensure correct settings regarding endpoint URL (including security policies), namespace indexes associated with desired items along with authentication credentials if required according to target server specifications.

#### Example Flow Demonstrating Basic Usage
Below demonstrates how one might set up basic communication between two systems utilizing aforementioned capabilities offered out-of-the-box after adding necessary libraries mentioned earlier.

[
    {
        "id": "opcua-read",
        "type": "OPCUA-IIoT in",
        "z": "",
        "name": "",
        "endpoint": "<your_opc_ua_server_endpoint>",
        "namespaceIndex": "3",
        "nodeId": "ns=3;s=MyVariable",
        "datatype": "float",
        "topic": "test/topic",
        "x": 290,
        "y": 80,
        "wires": [
            ["debug"]
        ]
    },
    {
        "id": "debug",
        "type": "debug",
        "z": "",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload"
    }
]

This JSON snippet represents part of a larger workflow definition file used when deploying applications built atop Node-RED framework. It shows setting up an input node configured against hypothetical OPC-UA compliant device accessible over network alongside connecting output destination for logging received data points locally during runtime execution cycle.

--related questions--

1. What are common troubleshooting steps for issues encountered while trying to connect to an OPC UA server?
2. How does one secure communications between Node-RED instances and industrial control systems supporting OPC UA protocols?
3. Can you provide examples demonstrating more advanced features supported by `node-red-contrib-opcua`, such as browsing namespaces programmatically?
4. Is there any official documentation source recommended for learning about best practices concerning implementation patterns involving both technologies together?