opcua

R2026b

Create OPC UA client object

Description

An opc.ua.Client object represents an OPC UA client in MATLAB^® that connects to an OPC UA server. Use this object to browse the server namespace, read and write current node values, access historical node data, and configure security settings for the connection.

Creation

Syntax

uaClient = opcua(serverInfoObj)

uaClient = opcua(serverUrl)

uaClient = opcua(hostname,portnum)

uaClient = opcua(___,Name=Value)

Description

uaClient = opcua(serverInfoObj) creates an OPC UA client for the server specified by serverInfoObj. You can create server info objects with the opcuaserverinfo function.

uaClient = opcua(serverUrl) creates a client for the server referenced by the URL specified in serverUrl.

uaClient = opcua(hostname,portnum) creates a client for the server at port portnum on the host identified by hostname.

uaClient = opcua(___,Name=Value) specifies one or more property values using name-value arguments. (since R2025a)

The client retrieves a list of all available connection endpoint configurations from the server. By default, the client selects the endpoint configuration with the highest available channel security policy and message security mode. If the attempt to retrieve endpoints fails, you can override the default settings by using the name-value arguments to set the properties MessageSecurityMode and ChannelSecurityPolicy.

Input Arguments

serverInfoObj — OPC UA server

opc.ua.ServerInfo object

OPC UA server to connect to, specified as an opc.ua.ServerInfo object.

serverUrl — OPC UA server URL

character vector | string

OPC UA server URL, specified as a character vector or string. The server URL must use the opc.tcp protocol. Industrial Communication Toolbox™ does not support http or https connections to an OPC UA server.

Data Types: char | string

hostname — Server hostname or IP address

char | string

Server hostname or IP address, specified as a character vector or string. A hostname can be short or a fully qualified domain name.

Example: 'localhost'

Data Types: char | string

portnum — Server host port number

numeric

Server host port number, specified as a numeric value.

Example: 5000

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: uaClient = opcua("opc.tcp://localhost:53530/OPCUA/SimulationServer",MessageSecurityMode="SignAndEncrypt",ChannelSecurityPolicy="Aes256_Sha256_RsaPss");

MessageSecurityMode — Client message security mode

"SignAndEncrypt" | "Sign" | "None"

Since R2025a

Client message security mode, specified as "SignAndEncrypt" or "Sign" or "None". By default, the function chooses the highest message security mode available on the server. For more information, see Message Security Modes.

Example: uaClient = opcua("localhost", 53530,MessageSecurityMode="Sign");

Data Types: char | string

ChannelSecurityPolicy — Client channel security policy

"Aes256_Sha256_RsaPss" | "Basic256Sha256" | "Aes128_Sha256_RsaOaep" | "None"

Since R2025a

Client channel security policy, specified as "Aes256_Sha256_RsaPss", "Basic256Sha256", "Aes128_Sha256_RsaOaep", or "None". By default, the function chooses the highest channel security policy available on the server. For more information, see Channel Security Policies.

Example: uaClient = opcua("localhost", 53530,ChannelSecurityPolicy="Basic256Sha256");

Data Types: char | string

Note

Security Considerations: When you communicate with an OPC UA server, use the highest available channel security policy and message security mode.

If you set the MessageSecurityMode and ChannelSecurityPolicy to "None", the messages are sent as clear text because they are not signed and encrypted. Use this setting only in a trusted environment.

For an OPC UA server that does not support a security policy, request the server administrator to enable a channel security policy and message security mode for the server other than None. These settings enable encryption and authentication for your data and operations.

UseDiscoveryHostname — Option to replace endpoint URL hostname with input URL hostname

false (default) | true

Since R2025a

Option to replace the endpoint URL hostname with the input hostname or IP address provided in serverUrl, specified as one of these:

• true: The function replaces the hostname in the endpoint URL returned by the server with the input hostname or IP address provided in serverUrl.

• false: The function retains the endpoint URL provided by the server.

Example: uaClient = opcua("opc.tcp://DNShost:53530/OPCUA/SimulationServer",UseDiscoveryHostname=true);

Data Types: logical

Note

Security Considerations: You modify the endpoint URL returned by the server when you set UseDiscoveryHostname to true. Use this setting only in a trusted environment.

If you need to connect to an OPC UA server through a NAT router, make sure that the server returns all discoverable endpoints to a calling client.

TrustServerTemporarily — Option to trust server temporarily

false (default) | true

Since R2026a

Option to trust a server temporarily for the current OPC UA client, specified as true or false.

Example: uaClient = opcua("opc.tcp://DNShost:53530/OPCUA/SimulationServer",TrustServerTemporarily=true);

Data Types: logical

Note

Security Considerations: You allow connection with a server whose certificate is not included in the MATLAB OPC UA client's trusted certificate store when you set TrustServerTemporarily to true. Use this setting only in a trusted environment.

If you trust the server source, consider using the opc.ua.trustServerCertificate function to permanently add the server certificate to the MATLAB OPC UA client's trusted certificate store. When a server certificate is included in the MATLAB OPC UA client's trusted certificate store, you can connect to the server from any OPC UA client created from the local system.

DebugLogging — Option to enable debug logging

false | true

Since R2026b

Option to enable debug logging for OPC UA clients, specified as true or false. When you set the debug logging option, MATLAB applies the logging state to all OPC UA clients in the current session. For more information, see DebugLogging.

Example: uaClient = opcua("opc.tcp://DNShost:53530/OPCUA/SimulationServer",DebugLogging=true);

Data Types: logical

Output Arguments

uaClient — OPC UA client

opc.ua.Client object

OPC UA client, returned as an opc.ua.Client object, with these Properties.

Properties

Server Information

Name — Name of server

Read-only: character vector

This property is read-only.

Name of the OPC UA server the client connects to, represented as a character vector.

Example: 'SimulationServer@MyMachine-4u6B'

Data Types: char

Hostname — Server hostname or IP address

Read-only: character vector

This property is read-only.

Server hostname or IP address, represented as a character vector.

Example: 'MyMachine-4u6B'

Data Types: char

Port — Port number for connecting to server

Read-only: double

This property is read-only.

Port number used for TCP/IP connections to the server, represented as a double.

Example: 53530

Data Types: double

EndpointUrl — URL for connecting to server

Read-only: character vector

This property is read-only.

URL used for connecting to the server, represented as a character vector. This URL uniquely identifies the endpoint and includes the security mode, security policy, and transport settings information associated with that endpoint.

Example: 'opc.tcp://MyMachine-4u6B:53530/OPCUA/SimulationServer'

Data Types: char

Connection Information

Timeout — Maximum time to wait for all operations on server to complete

Read-only: double

This property is read-only.

Maximum time in seconds to wait for all operations on the server to complete, represented as a double.

Example: 10

Data Types: double

Status — Status of client

Read-only: 'Disconnected' (default) | 'Connected'

This property is read-only.

Status of the client, represented as 'Disconnected' or 'Connected'. When you create a client, it is disconnected by default. Use connect to connect the client to the server.

Example: 'Connected'

ServerState — State of server

Read-only: character vector

This property is read-only.

State of the server, represented as a character vector. An OPC UA server can be in one of these states: 'Running', 'Failed', 'No Configuration', 'Suspended', 'Shutdown', 'Test', 'Comms Fault', 'Unknown'. When the client is not connected to the server, the server state is shown as '<Not connected>'.

Example: 'Running'

Data Types: char

Security Information

MessageSecurityMode — Message security mode used for connection

Read-only: SignAndEncrypt | Sign | None

This property is read-only.

Message security mode used for connection, represented as SignAndEncrypt, Sign, or None.

Example: SignAndEncrypt

Data Types: enumerated

ChannelSecurityPolicy — Channel security policy used for connection

Read-only: Aes256_Sha256_RsaPss | Basic256Sha256 | Aes128_Sha256_RsaOaep | None

This property is read-only.

Channel security policy used for connection, represented as Aes256_Sha256_RsaPss, Basic256Sha256, Aes128_Sha256_RsaOaep, or None.

Example: Basic256Sha256

Data Types: enumerated

Endpoints — Endpoints discovered by client

Read-only: array of endpoints

This property is read-only.

Endpoints discovered by the OPC UA client, represented as an array of endpoints. To access the description for all the endpoints, use the syntax clientObj.Endpoints.

Example:

>> clientObj.Endpoints

ans = 

1×11 OPC UA EndpointDescription array:
    index  Message Security    Channel Security                User Tokens            
    -----  ----------------  ---------------------  ----------------------------------
      1    SignAndEncrypt    Aes256_Sha256_RsaPss   Anonymous | Username | Certificate
      2    Sign              Basic256               Anonymous | Username | Certificate
      3    Sign              Aes128_Sha256_RsaOaep  Anonymous | Username | Certificate
      4    Sign              Basic128Rsa15          Anonymous | Username | Certificate
      5    SignAndEncrypt    Basic256Sha256         Anonymous | Username | Certificate
      6    SignAndEncrypt    Basic128Rsa15          Anonymous | Username | Certificate
      7    None              None                   Anonymous | Username | Certificate
      8    Sign              Basic256Sha256         Anonymous | Username | Certificate
      9    SignAndEncrypt    Basic256               Anonymous | Username | Certificate
     10    Sign              Aes256_Sha256_RsaPss   Anonymous | Username | Certificate
     11    SignAndEncrypt    Aes128_Sha256_RsaOaep  Anonymous | Username | Certificate

Diagnostic Information

DebugLogging — Logging state of OPC UA client

Read-only: logical

Since R2026b

This property is read-only.

Logging state of OPC UA client, represented as a logical 0 (logging disabled) or 1 (logging enabled). When you set this property using the name-value argument DebugLogging, MATLAB sets the logging state for all OPC UA clients in the current session. When you delete all OPC UA clients from a session, the default state returns to logging disabled. To enable logging for clients created in the session after this reset, you must set the DebugLogging value to 1 again.

Example:

>> clientObj.DebugLogging

ans =

  logical

   1

Data Types: logical

The following properties are available only after you connect the client to the server.

Server Limits

MinSampleRate — Minimum sample rate supported by server

Read-only: duration

This property is read-only.

Minimum sample rate supported by the server, represented as a duration in seconds.

Example: 0 sec

Data Types: duration

MaxReadNodes — Maximum number of nodes supported per read operation

Read-only: integer

This property is read-only.

Maximum number of nodes supported per read operation, represented as an integer.

Example: 10000

Data Types: uint32

MaxWriteNodes — Maximum number of nodes supported per write operation

Read-only: integer

This property is read-only.

Maximum number of nodes supported per write operation, represented as an integer.

Example: 10000

Data Types: uint32

MaxHistoryReadNodes — Maximum number of nodes supported for historical read operations

Read-only: integer

This property is read-only.

Maximum number of nodes supported for historical read operations, represented as an integer.

Example: 10000

Data Types: uint32

MaxHistoryValuesPerNode — Maximum number of history values returned per node

Read-only: double

This property is read-only.

Maximum number of history values returned per node during a historical read operation, represented as a double. When the server does not impose a limit, the property value is 0.

Example: 1000

Data Types: double

Object Functions

setSecurityModel	Set security configuration parameters for OPC UA client
connect	Connect OPC UA client to server
disconnect	Disconnect OPC UA client from server
isConnected	Determine if OPC UA client object is connected to server
getServerStatus	Status of OPC UA server
getNamespace	Namespace of OPC UA server associated with client
browseNamespace	Graphically browse namespace and select nodes from OPC UA server
readAtTime	Read historical data from nodes of OPC UA server at specific times
readHistory	Read historical data from nodes on OPC UA server
readProcessed	Read aggregate data from nodes of an OPC UA server
readValue	Read values from nodes on OPC UA server
subscribe	Monitor nodes for data change notification
writeValue	Write values to nodes on OPC UA server

Examples

Create OPC UA Client with Server Object

Create a client for the first server found on the local host.

s = opcuaserverinfo("localhost");
uaClient = opcua(s(1));

Create OPC UA Client with Discovery URL

Create a client using the discovery URL of the server.

uaClient = opcua("opc.tcp://localhost:53530/OPCUA/SimulationServer");

Create OPC UA Client with Hostname and Port Number

Create a client for the server at port 53530 on the local host.

uaClient = opcua("localhost",53530)

Create OPC UA Client and Configure Security Model

Since R2025a

Create a client using the discovery URL of the server and configure the security model.

uaClient = opcua("opc.tcp://MyMachine-4u6B:53530/OPCUA/SimulationServer",...
 MessageSecurityMode="SignAndEncrypt", ChannelSecurityPolicy="Aes256_Sha256_RsaPss");

View client details.

uaClient

uaClient = 

OPC UA Client:

   Server Information:
                     Name: 'SimulationServer@MyMachine-4u6B'
                 Hostname: 'MyMachine-4u6B'
                     Port: 53530
              EndpointUrl: 'opc.tcp://MyMachine-4u6B:53530/OPCUA/SimulationServer'

   Connection Information:
                  Timeout: 10
                   Status: 'Disconnected'
              ServerState: '<Not connected>'

   Security Information:
      MessageSecurityMode: SignAndEncrypt
    ChannelSecurityPolicy: Aes256_Sha256_RsaPss
                Endpoints: [1×11 opc.ua.EndpointDescription]

Create OPC UA Client and Configure Endpoint URL Hostname

Since R2025a

Create a client using the discovery URL of the server.

uaClient = opcua("opc.tcp://240.19.17.56:53530/OPCUA/SimulationServer");

View the endpoint URL returned by the server.

uaClient.EndpointUrl

ans =

    'opc.tcp://192.168.1.2:53530/OPCUA/SimulationServer'

Re-create the client and replace the endpoint URL hostname with discovery URL hostname.

uaClient = opcua("opc.tcp://240.19.17.56:53530/OPCUA/SimulationServer", UseDiscoveryHostname=true);

Verify that the endpoint URL is same as the discovery URL of the client.

uaClient.EndpointUrl

ans =

    'opc.tcp://240.19.17.56:53530/OPCUA/SimulationServer'

Create OPC UA Client and Enable Client Debug Logging

Since R2026b

Create an OPC UA client for a server on the localhost and enable debug logging.

uaClient1 = opcua("localhost",53530,DebugLogging=true);

Connect the client to the OPC UA server.

connect(uaClient1);

Create another OPC UA client using the server discovery URL and connect the client to the server.

uaClient2 = opcua("opc.tcp://MyMachine-4u6B:53530/OPCUA/SimulationServer");
connect(uaClient2);

As debug logging is enabled in this session, logging remains active for the new client. To confirm the logging state, query the DebugLogging property.

uaClient2.DebugLogging

ans =

  logical

   1

Save the generated log to the current directory and open it in the MATLAB editor.

logFile = opc.ua.saveClientLog();
open(logFile);

This saved file includes debug logs from both OPC UA clients in the session.

Version History

Introduced in R2015b

R2026b: Enable Debug Logging

The MATLAB OPC UA client now supports debug logging. To enable logging for all clients in a session, set the DebugLogging property of any client to 1.

R2026b: Automatic session recovery

The MATLAB OPC UA client now automatically recovers disrupted sessions by reconnecting and resuming operations after temporary network interruptions.

R2025a: Configure Security Model and Endpoint URL Hostname

The MATLAB OPC UA client now supports configuring the security model and endpoint URL hostname at client creation. To specify these settings, use the name-value arguments MessageSecurityMode, ChannelSecurityPolicy, and UseDiscoveryHostname.