Add OPC-UA Connection - How To

You can add an OPC-UA connection through the Kelvin UI, Kelvin SDK and Kelvin API.

Connections was formerly called Bridges. You will find the Kelvin SDK and Kelvin API commands still refer to Connections as Bridges.

Kelvin UIKelvin SDKKelvin API

Kelvin UI

You can watch this short demo video or read the full step-by step written tutorial below.

To start click on the Connections menu option from the left side bar menu.

click on the Create Connection button.

Step 1

Select the OPC UA option and click Next.

Step 2

Type in a memorable name in the Connection Display Name text input. You can use any letters, numbers and special characters.

The Connection Name text input will be automatically converted and filled in as you type in the Connection Display Name section. The conversion ensures the Connection Name only contains lowercase alphanumeric characters and ., _ or - characters.

Then select which Cluster to deploy the new Connector to.

It is important that the asset is reachable from the selected Cluster.

Step 3

Configure the OPC-UA connection to the asset. There are a number of optional and mandatory parameters to fill in.

For the optional parameters, if you do not fill in any values, the default values will be used.

Parameter	Options	Description	Default	Mandatory
Read Timeout	Numeric value (in milliseconds)	Specifies the maximum time to wait for a response when reading data from an OPC UA server.		No
Write Timeout	Numeric value (in milliseconds)	Specifies the maximum time to wait for a response when writing data to an OPC UA server.		No
Watchdog Timeout	Numeric value (in milliseconds)	Defines the timeout for the watchdog mechanism, which monitors the health of the connection to the OPC UA server.		No
Session Name	String	A custom name for the session, used for identification and logging purposes.		No
Endpoint URL	String (opc.tcp://localhost:48010)	The URL of the OPC UA server endpoint to connect to.		Yes
Verify SSL	Boolean (True/False)	Determines whether SSL certificates are verified when connecting to an OPC UA server over a secure channel.		Yes
Security Policy	String (specifying security type)	Specifies the security policy for the connection, such as `None`, `Basic256Sha256`, etc. This defines the level of security like encryption and data integrity.		Yes
Message Security	String (specifying security mode)	Determines the security mode of the messages, such as `None`, `Sign`, or `SignAndEncrypt`.	None	Yes
Authentication Method	String (specifying method)	Specifies the method of authentication used when connecting to the OPC UA server, such as `Credentials` or `Certificate`.	None	Yes
Username	String	The username used for authentication if the `Credentials` option is chosen in Authentication Method.		Depends
Password	String	The password corresponding to the username if the `Credentials` option is chosen in Authentication Method.		Depends
Certificates	File path or certificate object	The path to the certificate file(s) or the certificate object itself if the `Certificate` option is chosen in Authentication Method.		Depends
Key Password	String	The password for the private key associated with the client's certificate if the `Certificate` option is chosen in Authentication Method.		Depends

Step 4

Download, complete, and upload the available template to define the mapping connections between the OPC UA address and the Asset/Data Stream.

You can only upload one file. Multiple file uploads is not allowed and only the latest selected file will be used.

Do not modify the header in the downloaded template file. In the next step the header will be checked to ensure the csv structure is correct. Start adding your data from row 2 onwards.

Header	Description	Example	Mandatory
DataStream Name	The Kelvin Data Stream name (must be lowercase alphanumeric with no spaces)	water-flow	Yes
Asset Name	The Kelvin Asset name (must be lowercase alphanumeric with no spaces)	well-01	Yes
DataStream Type	The type of data (boolean, number, object and string)	number	No
Access	Read/Write (RW) or Read Only (RO)	RO	Yes
Storage	Location of the storage; "none", "node", "node-and-cloud"	node-and-cloud	No
Node ID	OPC UA data address	ns=4;i=1002	Yes
Polling Rate (in seconds)	How often to pull the data from the asset	30	Yes

Step 5

The file will now be validated before you can initiate the connection with the following checks;

Structure
- All required columns are present
- Columns naming is correct
- File has content below the header
Content
- Required Fields (Data Stream Name, Asset Name and Access fields are properly filled)
- Content Matches the patterns and is valid content
- No duplicate content has been detected
System
- All Assets exist on the system
- All Data Stream exist on the system

If there are any errors, you can view the details by clicking on the Show Errors button.

After looking at the error list, you will need to correct your csv file and then return to Step 4 to re-upload. The new file will then be checked and validated again.

When everything is validated, then you can click on Connect button to deploy the Connector to the Cluster. It will start automatically, connect to the asset and start collecting data.

Then in Kelvin UI under Connections you will see your Connection deployed and running.

If you have any issues in the deployment and the Add Connection fails to run, then you can check its logs.

Kelvin SDK

You can add a new OPC-UA Connection using the following command;

Make sure you are logged into your Kelvin before running.

$ kelvin bridge deploy --help
Usage: kelvin bridge deploy [OPTIONS]

  Deploy a bridge with specified parameters. e.g. kelvin bridge deploy
  --bridge-name "test-bridge" --cluster-name "my-node" --protocol "opc-ua"
  --bridge-config "/path/to/app.yaml"

Options:
  --cluster-name TEXT   The name of the cluster (or node) to deploy the bridge
                        to.  [required]
  --bridge-name TEXT    The friendly name of the bridge.  [required]
  --protocol TEXT       The protocol to be used by the bridge. May be one of:
                        [opc-ua, mqtt, modbus, roc]  [required]
  --bridge-title TEXT   The title of the bridge.
  --bridge-config PATH  The configuration file (e.g. app.yaml) to be used by
                        the bridge.  [required]
  -v, --verbose         Display all executed steps to the screen.
  --help                Show this message and exit.

Option	Description
cluster-name	This is the name of the Kelvin Cluster where you want to deploy the Connection. (Note: This is not the Title but the name which can not include spaced).
bridge-name	This is the name for the Connection. It must be all lowercase and cannot include spaces and any special characters except "-" and "_". It also must start with a alphabet letter.
protocol	This will be `opc-ua`
bridge-title	This is a friendly name for the Connection. It can include special characters and spaces. If using spaces, make sure to wrap your title with quotation marks.
bridge-config	This is a file with all the Kelvin Asset / Kelvin Data Stream information and their links to the asset addresses. Note : More information on this file will come after testing is completed.

Create a yaml file called opcua.yaml and put the following information inside;

app:
  bridge:
    configuration:
      authentication:
        type: none
      connection:
        endpoint_url: opc.tcp://uademo.prosysopc.com:53530/OPCUA/SimulationServer
        message_security: none
        security_policy: none
        verify_ssl: false
    language:
      cpp:
        dso: kelvin_bridge_opcua_client/kelvin_bridge_opcua_client.so
      type: cpp
    logging_level: INFO
    metrics_map:
    - access: RO
      asset_name: docs-demo-bridge
      configuration:
        node: ns=4;i=1002
        polling_rate: 30
        scale_multiplier:
      data_type: raw.float64
      name: docs-demo-bridge-opc-ua
    protocol: OPCUA
    system_packages:
    - libxml2
    - libcurl3-gnutls
  type: bridge
info:
  description: Kelvin Bridge OPCUA Client
  name: kelvin-bridge-opcua-client
  title: Kelvin Bridge OPCUA Client
  version: 3.3.3
spec_version: 4.10.0

Then run the command in the terminal;

kelvin bridge deploy --cluster-name docs-demo-cluster-k3s --bridge-name docs-demo-bridge-opc-ua --protocol opc-ua --bridge-title "Docs Demo Bridge OPC-UA" --bridge-config opcua.yaml --verbose

You should see a response similar to this;

[kelvin.sdk][2023-12-07 15:42:46][R]
Bridge "docs-demo-bridge-opc-ua" successfully deployed.

Then you can check the status with kelvin bridge list command.

It will only show here when it is running on the edge. If it is pending deploy, it will not show here. You can see the actual status of the Connections in the Kelvin UI.

[kelvin.sdk][2023-12-07 20:08:26][I] Retrieving bridges..
[kelvin.sdk][2023-12-07 20:08:28][I] *************************** Bridges ***************************
+-------------------------------+-------------------------------------+------------------------+-------------------------------+------------+----------------------------------+----------------------------------+
| Name                          | Title                               | Node name              | Workload name                 | Protocol   | Created                          | Updated                          |
|-------------------------------+-------------------------------------+------------------------+-------------------------------+------------+----------------------------------+----------------------------------|
| docs-demo-bridge-opc-ua       | Docs Demo Bridge OPC-UA             | docs-demo-cluster-k3s  | docs-demo-bridge-opc-ua       | opc-ua     | 2023-12-07 12:38:39.045767+00:00 | 2023-12-07 12:38:39.045767+00:00 |
+-------------------------------+-------------------------------------+------------------------+-------------------------------+------------+----------------------------------+----------------------------------+

Or in Kelvin UI under Connections you will see your Connection deployed and running.

If you have any issues in the deployment and the kelvin bridge deploy fails to run, then you can check its logs.

Kelvin API

/bridges/deploy

The API request POST for adding a new OPC-UA Connection can be done with the /bridge/deploy request POST.

You can easily make a new OPC-UA Connection by using the Request Body like this;

{
  "name": "docs-demo-bridge-opc-ua",
  "title": "Docs Demo Bridge OPC-UA",
  "cluster_name": "docs-demo-cluster-k3s",
  "workload_name": "docs-demo-bridge-opc-ua",
  "protocol": "opc-ua",
  "payload": {
    "configuration": {
      "authentication": {
        "type": "none"
      },
      "connection": {
        "endpoint_url": "opc.tcp://uademo.prosysopc.com:53530/OPCUA/SimulationServer",
        "message_security": "none",
        "security_policy": "none",
        "verify_ssl": false
      }
    },
    "logging_level": "INFO",
    "metrics_map": [
      {
        "access": "RO",
        "asset_name": "docs-demo-bridge",
        "configuration": {
          "node": "ns=4;i=1002",
          "polling_rate": 30,
          "scale_multiplier": null
        },
        "data_type": "raw.float64",
        "name": "docs-demo-bridge-opc-ua"
      }
    ]
  }
}

Then in Kelvin UI under Connections you will see your Connection deployed and running.

If you have any issues in the deployment and the kelvin bridge deploy fails to run, then you can check its logs.