OPC PLC server

Implements an OPC-UA server with different nodes generating random data, anomalies and configuration of user defined nodes.

Features

The following nodes are part of the PLC simulation:

  • Alternating boolean
  • Random signed 32-bit integer
  • Random unsigend 32-bit integer
  • Sine wave with a spike anomaly
  • Sine wave with a dip anomaly
  • Value showing a positive trend
  • Value showing a negative trend

By default everything is enabled, use command line options to disable certain anomaly or data generation features. Additionally to those nodes with simulated data, a JSON configuration file allows nodes to be created as specified. Finally, the simulation supports a number of nodes of specific types that can change at a configurable rate.

Getting Started

Prerequisites

The implementation is based on .NET Core so it is cross-platform and the recommended hosting environment is Docker.

Installation

There is no installation required.

Quickstart

A Docker container of the component is hosted in the Microsoft Container Registry and can be pulled by:

docker pull mcr.microsoft.com/iotedge/opc-plc:<See version.json>

The tags of the container match the tags of this repository and the containers are available for Windows and Linux.

User node configuration via JSON configuration file

If the module (application) is started with the argument --nodesfile then the specified JSON configuration file is loaded. Nodes defined in the JSON file will be published by the server. This enables another OPC-UA client application to set the state/value of the node. Please note that nodes specified in the JSON file are NOT part of the simulation. They remain visible in an unchanged state until an OPC UA client changes their status. The following command shows how to start the application on a Windows host:

opcplc.exe --at X509Store --nodesfile nodesfile.json

Here's a sample node configuration file:

{
  "Folder": "MyTelemetry",
  "NodeList": [
    {
      "NodeId": 1023,
      "Name": "ActualSpeed",
      "Description": "Rotational speed"
    },
    {
      "NodeId": "aRMS"
    },
    {
      "NodeId": "1025",
      "Name": "DKW",
      "DataType": "Float",
      "ValueRank": -1,
      "AccessLevel": "CurrentReadOrWrite",
      "Description": "Diagnostic characteristic value"
    }
  ]
}
  • Folder: Defines the name of the folder under which the user specified nodes should be created. This folder is created below the root of the OPC UA server.
  • NodeList: Defines the list of nodes, which will be published by the emulated server. Nodes specified in the list can be browsed and changed by OPC UA applications. This enables developers to easyly implement and test OPC UA client applications.
  • NodeId: Specifies the identifier of the node and is required. This value can be a decimal or string value. Every other JSON type is converted to a string identifier.
  • Name: The display name of the tag. If not set it will be set to the NodeId. (Optional)
  • DataType: The OPC UA valid type. It specifies one of types defined by BuiltInType. If an invalid type is specified or if it is ommitted it defaults to 'Int32'. (Optional)
  • ValueRank: As defined by type ValueRanks. If omitted it will be set to the value '-1' (Scalar). (Optional)
  • AccessLevel: Specifies one of access levels defined by type AccessLevels. If an invalid access level is specified or if it is omitted it defaults to 'CurrentReadOrWrite'. (Optional)
  • Description: Description of the node. If not set it will be set to the NodeId. (Optional)

Slow and fast changing nodes

A number of changing nodes can be simulated with the following options. The nodes are categorized into slow and fast only for convenience.

  • sn: Number of slow nodes
  • sr: Rate in seconds at which to change the slow nodes (uint, default every 10 s)
  • st: Data type for slow nodes (UInt|Double|Bool|UIntArray, case insensitive)
  • fn: Number of fast nodes
  • fr: Rate in seconds at which to change the fast nodes (uint, default every 1 s)
  • ft: Data type for fast nodes (UInt|Double|Bool|UIntArray, case insensitive)

Data types

  • UInt: Increases by 1
  • Double: Increases by 0.1
  • Bool: Alternates
  • UIntArray: 32 values that increase by 1

Sample start command on a Windows host:

opcplc.exe --pn=50000 --at X509Store --autoaccept --nospikes --nodips --nopostrend --nonegtrend --nodatavalues --sph --sn=25 --sr=10 --st=uint --fn=5 --fr=1 --ft=uint

Sample start command for Docker:

docker run --rm -it -p 50000:50000 -p 8080:8080 --name opcplc mcr.microsoft.com/iotedge/opc-plc:latest --pn=50000 --autoaccept --nospikes --nodips --nopostrend --nonegtrend --nodatavalues --sph --sn=25 --sr=10 --st=uint --fn=5 --fr=1 --ft=uint

OPC Publisher file (pn.json)

The option sph shows and dumps a pn.json file that matches the configuration. In addition, a web server hosts the file on a configurable port (wp, default 8080): e.g. http://localhost:8080/pn.json

Build

The build scripts are for Azure DevOps and the container build is done in ACR. To use your own ACR you need to:

  • Create a service connection called azureiiot to the subscription/resource group in which your ACR is located
  • Set a variable called azureContainerRegistry with the name of your Azure Container Registry

Notes

X.509 certificates:

  • Running on Windows natively, you cannot use an application certificate store of type Directory, since the access to the private key will fail. Use the option --at X509Store in this case.
  • Running as Linux Docker container, you can map the certificate stores to the host file system by using the Docker run option -v <hostdirectory>:/appdata. This will make the certificate persistent over starts.
  • Running as Linux Docker container using an X509Store for the application certificate, you need to use the Docker run option -v x509certstores:/root/.dotnet/corefx/cryptography/x509stores and the application option --at X509Store

Resources