Connectors.OPCUA

This document describes the Connectors.OPCUA module for RaaLabs Edge.

What does it do?

The connector reads nodes from a OPC UA server. A node is identified by a node id, consisting of a namespace index and an identifier, e.g. ns=3;i=1002.

The connector are producing events of type [OutputName("output")] and should be routed to IdentityMapper.

Configuration

The module is configured using a JSON file. connector.json represents the connection to the TCP or UDP stream using IP and port. The following example json works with the Prosys OPC UA Simulation Server.

{
    "serverUrl": "opc.tcp://<HOST>:<PORT>/<SERVERNAME>",
    "publishingIntervalSeconds": 1.0,
    "nodes": [
        {
            "nodeId": "ns=3;i=1002",
            "subscribeIntervalSeconds": 1.0,
            "readIntervalSeconds": 1.0
        },
        {
            "nodeId": "ns=3;i=1001",
            "readIntervalSeconds": 1.0
        }
    ]
}

IoT Edge Deployment

$edgeAgent

In your deployment.json file, you will need to add the module. For more details on modules in IoT Edge, go here.

The module has persistent state and it is assuming that this is in the config folder relative to where the binary is running. Since this is running in a containerized environment, the state is not persistent between runs. To get this state persistent, you'll need to configure the deployment to mount a folder on the host into the config folder.

In your deployment.json file where you added the module, inside the HostConfig property, you should add the volume binding.

"Mounts": [
   {
        "Type": "volume",
        "Source": "raalabs-config-opcua",
        "Target": "/app/config",
        "RW": false
    }
]

{
    "modulesContent": {
        "$edgeAgent": {
            "properties.desired.modules.OPCUA": {
                "settings": {
                    "image": "<repo-name>/connectors-opcua:<tag>",
                    "createOptions": {
                        "HostConfig": {
                            "Mounts": [
                                {
                                    "Type": "volume",
                                    "Source": "raalabs-config-opcua",
                                    "Target": "/app/config",
                                    "RW": false
                                }]}
                },
                "type": "docker",
                "version": "1.0",
                "status": "running",
                "restartPolicy": "always"
            }
        }
    }
}

$edgeHub

The routes in edgeHub can be specified like the example below.

{
    "$edgeHub": {
        "properties.desired.routes.OPCUAToIdentityMapper": "FROM /messages/modules/OPCUA/outputs/output INTO BrokeredEndpoint(\"/modules/IdentityMapper/inputs/events\")",
    }
}

Testing using Prosys OPC UA Simulation Server

Prosys offers a free simulation server, which can be downloaded here: https://downloads.prosysopc.com/opc-ua-simulation-server-downloads.php.

The OPC UA server starts automatically once you launch the application. Under Objects, you can browse the nodes present in the server, and navigating and clicking the individual nodes, you can find the nodes NodeId, which you can use in the configuration.json to test the connector using the simulator.

The simulator also displays the server url (connection address) once you start the simulator.