ua.client.TdOPCUAClient

Component to connect to an OPC UA server.

Delphi

TdOPCUAClient = class(TComponent);

C++

class TdOPCUAClient : public TComponent;

Description

With the TdOPCUAClient it is possible to connect to any OPC UA Server via the binary protocol (opc.tcp://...). The usage of the our UA component is very easy. All connect and disconnect activities are done in the component. But please note: With this component it is not possible to connect to other OPC server like OPC Classic COM server or OPC XML DA server, this can be done e.g. with our TdOPCDAClient component.

Here is an example how you can connect to an OPC UA server:

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uses ua.client; procedure OPCUAConnect(OPCClient : TdOPCUAClient); begin OPCClient.URL := 'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer'; OPCClient.Active := true; ShowMessage('Connected to server'); end;

The TdOPCUAClient supports all OPC UA Service calls which are in detailed descript in the OPC UA Specification (Part 4: Services) You can download the specification at: https://www.opcfoundation.org

It is recommended to read the OPC UA Specification Part 4 first.

Below you will find an example how you can make an service call with the TdOPCUAClient component. You will find all Pascal implementations of the OPC UA data types and service calls descript in the OPC UA Spec. Part 4 in the unit ua.datatypes. All OPC UA basic build in types are implemented in the unit ua.buildinTypes.

The example shows you how to call the GetEndpoints service. For further information about this service, look at: OPC UA Specification Part 4 Discovery Service Set "GetEndpoints".

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uses // includes all datatypes specified in OPC UA Spec Part 4 (Services) ua.datatypes; procedure CallGetEndpoints(UAClient: TdOPCUAClient; Info: TStrings); var S: uaGetEndpoints; Endpoint: uaEndpointDescription; begin S := uaGetEndpoints.Create(UAClient); try S.Request.EndpointUrl := UAClient.Url; S.Run; for Endpoint in S.Response.Endpoints do Info.Add('+ '+Endpoint.EndpointUrl); finally S.Free; end; end;

You can call all other OPC UA service calls in the same way.

Here an template how to use:

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var ServiceCall: ua<NameOfServiceCall> // NameOfServiceCall = Service descripted in Part 4 begin ServiceCall := ua<NameOfServiceCall>.Create(<TdOPCUAClientObject>) try ServiceCall.Request.<InputParam> := <InputParamValue> ServiceCall.Run; ServiceCall.Response.<OutputParam> finally ServiceCall.Free; end; end;

Below you will find all OPC UA Service calls ua<NameOfServiceCall> which are supported by the dOPC Client Toolkit and in detail descript in the OPC UA Specification Part 4 Services.

OPC UA Service call	Description
uaFindServers	Finds the servers known to the discovery server.
uaFindServersOnNetwork	Returns the Servers known to a Discovery Server
uaGetEndpoints	Gets the endpoints used by the server.
uaRegisterServer	Registers a server with the discovery server.
uaRegisterServer2	Is implemented by Discovery Servers
uaOpenSecureChannel	Creates a secure channel with a server.
uaCloseSecureChannel	Closes a secure channel.
uaCreateSession	Creates a new session with the server.
uaActivateSession	Activates a session with the server.
uaCloseSession	Closes a session with the server.
uaCancel	Cancels an outstanding request.
uaAddNodes	Adds one or more nodes to the server address space.
uaAddReferences	Adds one or more references to the server address space.
uaDeleteNodes	Delete one or more nodes from the server address space.
uaDeleteReferences	Delete one or more references from the server address space.
uaBrowse	Browse the references for one or more nodes from the server address space.
uaBrowseNext	Continues one or more browse operations.
uaTranslateBrowsePathsToNodeIds	Translates one or more paths in the server address space.
uaRegisterNodes	Registers one or more nodes for repeated use within a session.
uaUnregisterNodes	Unregisters one or more previously registered nodes.
uaQueryFirst	This Service is used to issue a Query request to the Server
uaQueryNext	look at OPC UA Spec Part 4 Services
uaRead	Is used to read one or more Attributes or Nodes.
uaHistoryRead	look at OPC UA Spec Part 4 Services
uaWrite	Is used to write values to one or more Attributes or Nodes
uaHistoryUpdate	look at OPC UA Spec Part 4 Services
uaCall	Is used to call a list of Methods
uaCreateMonitoredItems	look at OPC UA Spec Part 4 Services
uaModifyMonitoredItems	look at OPC UA Spec Part 4 Services
uaSetMonitoringMode	look at OPC UA Spec Part 4 Services
uaSetTriggering	look at OPC UA Spec Part 4 Services
uaDeleteMonitoredItems	look at OPC UA Spec Part 4 Services
uaModifySubscription	look at OPC UA Spec Part 4 Services
uaSetPublishingMode	look at OPC UA Spec Part 4 Services
uaPublish	look at OPC UA Spec Part 4 Services
uaRepublish	look at OPC UA Spec Part 4 Services
uaTransferSubscriptions	look at OPC UA Spec Part 4 Services
uaDeleteSubscriptions	look at OPC UA Spec Part 4 Services
uaCreateSubscription	look at OPC UA Spec Part 4 Services

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