Getting Started with PLCcom.Opc.Ua.Sdk

Important note

What is OPC UA?

What PLCcom.Opc.Ua.Sdk has to offer

• Data Access (read, write, browse, monitor)
• Alarm and Conditions
• Historical Data and Historical Events
• Complex / Structured Data Types
• Reverse Connect

• opc.tcp — binary UA TCP transport
• opc.https — secure HTTPS transport

• Easy to use — many functions can be called with a single line of code
• Path-based node addressing — address nodes by browse path (e.g. Objects.Plant.Line1.Machine1.Temperature) in addition to classic NodeIds
• Automatic Connect, Reconnect, and Disconnect — the connection state does not need to be monitored by the developer
• Active keep-alive monitoring of the server state
• Full Client SDK and Server SDK in a single assembly
• Extensive tutorials for C# and Visual Basic included

OPC UA Client SDK

Discover endpoints

C#Copy
EndpointDescriptionCollection endpoints = UaClient.GetEndpoints(
    new Uri("opc.tcp://localhost:48410"));
VBCopy
Dim endpoints As EndpointDescriptionCollection = UaClient.GetEndpoints(
    New Uri("opc.tcp://localhost:48410"))

Create a client instance

C#Copy
SessionConfiguration sessionConfig = SessionConfiguration.Build(
    "MyApplication", endpoints[0]);

UaClient client = new UaClient("[Enter your UserName here]", 
    "[Enter your Serial here]", 
    sessionConfig);

//register events
client.ServerConnected      += Client_ServerConnected;
client.ServerConnectionLost += Client_ServerConnectionLost;
client.CertificateValidation += (sender, e) => { e.Accept = true; };
VBCopy
Dim sessionConfig As SessionConfiguration = SessionConfiguration.Build(
    "MyApplication", endpoints(0))

Dim client As New UaClient("[Enter your UserName here]",
    "[Enter your Serial here]",
    sessionConfig)

'register events
AddHandler client.ServerConnected, AddressOf Client_ServerConnected
AddHandler client.ServerConnectionLost, AddressOf Client_ServerConnectionLost
AddHandler client.CertificateValidation, Sub(sender, e) e.Accept = True

Read and write by path

C#Copy
//resolve a node by path
NodeId nodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature");

//read a value
DataValue value = client.ReadValue(nodeId);

//write a value
client.WriteValue(nodeId, 23.5);
VBCopy
'resolve a node by path
Dim nodeId As NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature")

'read a value
Dim value As DataValue = client.ReadValue(nodeId)

'write a value
client.WriteValue(nodeId, 23.5)

C#Copy
NodeId nodeId = new NodeId("ns=2;i=10001");
DataValue value = client.ReadValue(nodeId);
VBCopy
Dim nodeId As NodeId = New NodeId("ns=2;i=10001")
Dim value As DataValue = client.ReadValue(nodeId)

Read and write multiple values

C#Copy
ReadValueIdCollection nodesToRead = new ReadValueIdCollection();

ReadValueId nodeToRead = new ReadValueId();
nodeToRead.NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature");
nodeToRead.AttributeId = Attributes.Value;
nodesToRead.Add(nodeToRead);

nodeToRead = new ReadValueId();
nodeToRead.NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.RPM");
nodeToRead.AttributeId = Attributes.Value;
nodesToRead.Add(nodeToRead);

DataValueCollection results = client.Read(nodesToRead);
VBCopy
Dim nodesToRead As New ReadValueIdCollection()

Dim nodeToRead As New ReadValueId()
nodeToRead.NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature")
nodeToRead.AttributeId = Attributes.Value
nodesToRead.Add(nodeToRead)

nodeToRead = New ReadValueId()
nodeToRead.NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.RPM")
nodeToRead.AttributeId = Attributes.Value
nodesToRead.Add(nodeToRead)

Dim results As DataValueCollection = client.Read(nodesToRead)

Monitor value changes

C#Copy
Subscription subscription = new Subscription();
subscription.PublishingInterval = 1000;
client.AddSubscription(subscription);

NodeId nodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature");
MonitoredItem monitoredItem = new MonitoredItem(subscription.DefaultItem)
{
    StartNodeId      = nodeId,
    SamplingInterval = 500,
    QueueSize        = uint.MaxValue,
    DisplayName      = "Temperature"
};

monitoredItem.Notification += (item, e) =>
{
    var notification = e.NotificationValue as MonitoredItemNotification;
    Console.WriteLine($"{item.DisplayName} = {notification.Value.Value}  " +
        $"Status: {notification.Value.StatusCode}");
};

subscription.AddItem(monitoredItem);
subscription.ApplyChanges();
subscription.SetPublishingMode(true);
subscription.Modify();
VBCopy
Dim subscription As New Subscription()
subscription.PublishingInterval = 1000
client.AddSubscription(subscription)

Dim nodeId As NodeId = client.GetNodeIdByPath("Objects.Plant.Line1.Machine1.Temperature")
Dim monitoredItem As New MonitoredItem(subscription.DefaultItem) With {
    .StartNodeId      = nodeId,
    .SamplingInterval = 500,
    .QueueSize        = UInteger.MaxValue,
    .DisplayName      = "Temperature"
}

AddHandler monitoredItem.Notification, Sub(item, e)
    Dim notification = TryCast(e.NotificationValue, MonitoredItemNotification)
    Console.WriteLine($"{item.DisplayName} = {notification.Value.Value}  " &
        $"Status: {notification.Value.StatusCode}")
End Sub

subscription.AddItem(monitoredItem)
subscription.ApplyChanges()
subscription.SetPublishingMode(True)
subscription.Modify()

OPC UA Server SDK

Configure and start a server

C#Copy
var config = new UaServerConfiguration
{
    ApplicationName = "My OPC UA Server",
    ApplicationUri  = "urn:mycompany:myserver",
    BaseAddresses   = new List<string>
    {
        "opc.tcp://localhost:48410",
        "opc.https://localhost:48411"
    }
};

var server = new UaServer();
await server.StartAsync(config);
VBCopy
Dim config As New UaServerConfiguration With {
    .ApplicationName = "My OPC UA Server",
    .ApplicationUri  = "urn:mycompany:myserver",
    .BaseAddresses   = New List(Of String) From {
        "opc.tcp://localhost:48410",
        "opc.https://localhost:48411"
    }
}

Dim server As New UaServer()
Await server.StartAsync(config)

Build the address space

C#Copy
UaFolder plant = server.CreateFolder("Plant");
UaFolder machine = server.CreateFolder(plant, "Machine1");

UaVariable<double> temperature = server.CreateVariable<double>(
    machine, "Temperature", initialValue: 20.0);
UaVariable<int> rpm = server.CreateVariable<int>(
    machine, "RPM", initialValue: 0);
UaVariable<bool> running = server.CreateVariable<bool>(
    machine, "IsRunning", initialValue: false);

//update values at runtime
temperature.Value = 23.5;
rpm.Value = 1500;
VBCopy
Dim plant As UaFolder = server.CreateFolder("Plant")
Dim machine As UaFolder = server.CreateFolder(plant, "Machine1")

Dim temperature As UaVariable(Of Double) = server.CreateVariable(Of Double)(
    machine, "Temperature", initialValue:=20.0)
Dim rpm As UaVariable(Of Integer) = server.CreateVariable(Of Integer)(
    machine, "RPM", initialValue:=0)
Dim running As UaVariable(Of Boolean) = server.CreateVariable(Of Boolean)(
    machine, "IsRunning", initialValue:=False)

'update values at runtime
temperature.Value = 23.5
rpm.Value = 1500

Add methods

C#Copy
server.CreateMethod(machine, "Reset",
    handler: (session, context, input, output) =>
    {
        temperature.Value = 0.0;
        rpm.Value = 0;
        return ServiceResult.Good;
    });
VBCopy
server.CreateMethod(machine, "Reset",
    handler:= Function(session, context, input, output)
                  temperature.Value = 0.0
                  rpm.Value = 0
                  Return ServiceResult.Good
              End Function)

User authentication

C#Copy
server.AddUser("operator", "secret123", Role.Operator);
server.AddUser("admin",    "admin456",  Role.Engineer);
VBCopy
server.AddUser("operator", "secret123", Role.Operator)
server.AddUser("admin",    "admin456",  Role.Engineer)

Server SDK features

• Folders, Variables (scalar + array), Objects, Methods
• Custom ObjectTypes and VariableTypes
• NodeSet2 XML import
• Alarm & Conditions
• Historical Data Access and Historical Events
• Simple Events
• Reverse Connect
• User authentication with roles
• Multiple namespaces
• Configurable security policies
• opc.tcp and opc.https transport
• Integrated logging via LogMessage event

System requirements

• Microsoft .NET Framework 4.7.2 or higher (up to 4.8.1)
• Microsoft .NET 5.0 to 7.0 via .NET Standard 2.1
• Microsoft .NET 8.0
• Microsoft .NET 9.0
• Microsoft .NET 10.0

• Visual Studio 2022 or higher (VS2026 recommended)

Licensing

C#Copy
//client
UaClient client = new UaClient("[Enter your UserName here]", 
    "[Enter your Serial here]", 
    sessionConfiguration);

//server
UaServer server = new UaServer("[Enter your UserName here]", 
    "[Enter your Serial here]");
VBCopy
'client
Dim client As New UaClient("[Enter your UserName here]",
    "[Enter your Serial here]",
    sessionConfiguration)

'server
Dim server As New UaServer("[Enter your UserName here]",
    "[Enter your Serial here]")