Connecting to the OPC UA Interface

The SMART’s OPC UA Model is accessible from any client supporting the OPC UA standards (for example, the popular UAExpert client). You can connect to the server using multiple different methods, depending on your network configuration.

The underlying interface is built from the open62541 Server libraries and supports all of the OPC UA foundation’s commands and controls. The server supports OPC UA client/server communication, subscriptions, events, method calls and the full range of security paradigms (encryption). The controller’s Information Model is built upon the OPC Foundation UA-Model Compiler which utilizes the UA Model Design.xsd core file.

You can connect to a SMART Controller's OPC UA server using either of the following URIs:
  • opc.tcp://hostname.domain:4840

    hostname is the SMART Controller's hostname provisioned during system configuration. Using this URI assumes hostname.domain can be found using your local DNS queries.

  • opc.tcp://IP Address:4840

    Using this form of the URI assumes the client you are using has access to the SMART Controller’s IP Address.

Security Certificates

Connecting to the SMART Controller's OPC UA server can be done with openssl certificates. The connection will abide by a Secure Certificate login when the appropriate x.509 certificates are properly exchanged.

On first start, the server will automatically create self-signed files server_cert.der and server_key.pem files in the /etc/ssl/private directory, if they do not already exist. You should copy these files to the appropriate location specified by your OPC UA client.

To have the SMART Controller automatically generate new certificates, remove the existing certificate files and restart the smart-opcua service using the command systemctl restart smart-opcua.
Important:
The certificates generated by the SMART Controller are self-signed and do not include any CA Trust authority. It is highly recommended you place your own certificates in the etc/ssl/private directory with the names server_cert.der and server_key.pem and restart the smart-opcua service.

Using openssl certificate methods mentioned above, these security policies & modes are supported:

  • Basic128Rsa15 (Sign, SignAndEncrypt)

  • Basic256 (Sign, SignAndEncrypt)

  • Aes256_Sha256_RsaPas (Sign, SignAndEncrypt)

  • Basic256Sha256 (Sign, SignAndEncrypt)

  • Aes128_Sha256_RsaOaep (Sign, SignAndEncrypt)