The data source input screen opens, in which you can select the OPC data source as “Type” as the first step.
However, if you first assign a name to the data source and this contains the word “opc“, “OPC” is already preselected as the data source type. (This works with all data source types)
Once this has been done, the data source-specific settings are automatically adapted to the OPC data source.
OPC Specific
- Connection type Here you can choose between OPC“Classic” DA and OPC“UA“.
- Discovery URL The Discovery URL connects you to the server and provides information on which target addresses are available with which settings.
- Endpoint URL The endpoint URL describes the server network address.
- Security mode Various security modes for communication with the server. You can choose between “None“, “Sign” and “Sign&Encrypt“.
- Authentication This controls the authentication options. You can choose between “Anonymous“, “UserName” and “Certificate“.
Create OPC UA data sources
If the “Connection type ” “UA” is selected, the server address can be entered under “Discovery URL“.
This then appears automatically under “Endpoint URL“. If you click on the magnifying glass icon, all endpoints with the different security levels provided by the server are displayed in a separate window.
If you select a security level, either via the “Select“button or by double-clicking, the security mode in the main screen automatically changes to “Sign“. Now you can enter a user name and a password under “Authentication” “UserName“.
If “Certificate” authentication is selected, the user uses a certificate to log in. The same applies to the “SignAndEncrypt” security mode, where you can also choose whether to log in anonymously, with a user name or via a certificate.
Trust in the server certificate
When establishing a connection, QuickHMI verifies the OPC UA server’s certificate. You can control this behavior using the “Automatically accept certificates” option:
- Enabled (default): Server certificates are automatically accepted (convenient for testing and commissioning).
- Disabled: The server certificate is checked against the central trust store . Unknown certificates appear under Rejected in the certificate manager and must be approved there once via Trust (see Managing Trust ).
⚠️ Important (Behavior Change After the Update)
For OPC UA data sources with “Automatically accept certificates” disabled, virtually every self-signed server certificate was previously accepted. Starting with this version, the server certificate is verified against the trust store.
Consequence: Existing connections to servers with self-signed certificates will fail after the update until the certificate has been trusted once: Certificate Manager → Rejected → Trust, then restart the instance. Data sources with Auto-Accept enabled are not affected.
Note (OPC Identity): The client identity for OPC UA is the central standard application certificate (see Certificate Manager)—it is not maintained on a per-data-source basis.
After entering the relevant information for the connection, click on “Add” or “Save” after editing a data source that has already been created.
The OPC UA data source is created and subsequently displayed in the data source overview.
Created data sources can be edited or deleted again. You can do this using the corresponding buttons. You also have the option to view all internal data sources. To do this, check the“Show internal data sources” checkbox.
In the article variables for the OPC UA data source describes how you can create them.
Explanation of the security modes of the OPC data source
There are 3 different security modes available in the main screen for communication with the server.
Security mode “None”:
- Possibility of “authentication” as anonymous or with user name and password.
(Depending on the configuration of the OPC UA server)
- Connection to the server, without encryption of the transmission.
(Username and password are transmitted unencrypted)
Sign” security mode:
- Possibility of “authentication” as anonymous, with user name and password, as well as via certificate.
- Data is transmitted in plain text, but signed.
SignAndEycrypt” security mode:
- Possibility of “authentication” as anonymous, with user name and password, as well as via certificate.
- Data is signed and transmitted in encrypted form.
