OPC-UA Device Service

Warning
The main branch of this repository contains work-in-progress development code for the upcoming release, and is not guaranteed to be stable or working. It is only compatible with the main branch of edgex-compose which uses the Docker images built from the main branch of this repo and other repos.

The source for the latest release can be found at Releases.

Documentation

For latest documentation please visit https://docs.edgexfoundry.org/latest/microservices/device/services/device-opc-ua/Purpose

Overview

This repository is a Go-based EdgeX Foundry Device Service which uses OPC-UA protocol to interact with the devices or IoT objects.

Features

1. Subscribe/Unsubscribe one or more variables (writable configuration)
2. Execute read command
3. Execute write command
4. Execute method (using Read command of device SDK)

Prerequisites

• Edgex-go: core data, core command, core metadata
• OPCUA Server (Prosys Simulation Server, for example)

Predefined configuration

Simulation Server

Download the Prosys OPC UA Simulation Server from here. Install and run it to have access to the default configured resources.

Configuration

Modify configuration.yaml file found under the ./cmd/res folder if needed

Pre-defined Devices

Define devices for device-sdk to auto upload device profile and create device instance. Please modify Simple_Devices.yaml file found under the ./cmd/res/devices folder.

This device service is currently limited to a single device instance.

Device Profile

A Device Profile can be thought of as a template of a type or classification of a Device.

Write a device profile for your own devices; define deviceResources and deviceCommands. Please refer to OpcuaServer.yaml.

Using Methods

OPC UA methods can be referenced in the device profile and called with a read command. An example of a method instance might look something like this:

deviceResources:
  -
    name: "SetDefaultsMethod"
    description: "Set all variables to their default values"
    properties:
      # Specifies the response value type
      valueType: "String"
      readWrite: "R"
    attributes:
      { methodId: "ns=5;s=Defaults", objectId: "ns=5;i=1111" }

deviceCommands:
  -
    name: "SetDefaults"
    isHidden: false
    readWrite: "R"
    resourceOperations:
      - { deviceResource: "SetDefaultsMethod" }

Notice that method calls require specifying the NodeId of both the method and its parent object.

The attributes field may also contain an inputMap: [] that passes parameters to the method, if applicable.

Build Instructions

1. Clone the device-rest-go repo with the following command:

   git clone https://github.com/edgexfoundry/device-opc-ua.git
   

2. Build a docker image by using the following command:

   make docker
   

3. Alternatively the device service can be built natively:

   make build
   

Testing

Running unit tests starts a mock OPCUA server on port 48408.

The mock server defines the following attributes:

Variable Name	Type	Default Value	Writable
ro_bool	Boolean	True
rw_bool	Boolean	True	✅
ro_int32	Int32	5
rw_int32	Int32	5	✅
square	Method	Int64 (return value)

All attributes are defined in ns=2.

# Install requirements (if necessary)
python3 -m pip install opcua
# Run tests
make test

Packaging

This component is packaged as docker images.

Please refer to the Dockerfile and Docker Compose Builder scripts.

Reference

• EdgeX Foundry Services
• Go OPCUA library
• OPCUA Server