OPC UA Server Connection Error

Below are some helpful troubleshooting steps to resolve connection errors with OPC UA server.

Bad Data Quality

Server Url

The Server Url under Configure-Drivers must be specified correctly to then browse for the available Security Profiles.

Configure Drivers

OPC UA Server Url

Refer to the OPC UA server vendors documentation for the correct endpoint of the server.

Once the Server Url is correctly set use the Browse button to select the Security Profile.

Certificate Authentication

If the OPC UA Server’s authentication certificate is rejected it will be placed in C:\ProgramData\OpenAutomationSoftware\pki\rejected\certs on Windows or the pki\rejected\certs sub-directory where the OAS Engine is located on Linux.  To resolve and move the OPC UA Server’s certificate file in the rejected\certs directory to trusted\certs.

OAS Certificate Creation

Version 18.0.0.17 of OAS added the ability to self create a certificate for OPC UA Servers and Clients to authenticate against.  Check the current version under Configure-System Status and if older than version 18.0.0.17 update the version of OAS if you are receiving a certificate authentication error under Configure-System Errors.

User Authentication

If the OPC UA Server requires a user name and password to validate the connection enable User Security under Configure-Drivers and specify the Username and Password that is required by the OPC UA Server.

Configure Drivers

OPC UA Username

System Errors

Select Configure-System Errors and expand any OPC UA or Driver Interface error to see the details of the error.

Menu Configure System Errors

The information provided can often help you determine the cause of communication failures.

The history of all systems errors can be found in the OAS Error Log specified under Configure-Options-System Logging.

Menu Configure Options

Error Log Path

Log OPC UA Communications

You can enable the OPC UA transaction logging under Configure-Options-System Logging to track all interface calls to the OPC UA server.

Menu Configure Options

OPC UA Transaction Logging

Specify the location of where the communication logs will be saved with the property Transaction Log Path further down in System Logging.

Transaction Log Path

There will be multiple files generated with the opc-ua within the file name and also the base OAS Transactions file.

UA Expert

The UA Expert program is a good test application to communicate to OPC UA server to verify the server can be interfaced with.

You can download UA Expert from https://filedownloads.openautomationsoftware.com/tools/uaexpert.zip.

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