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Access OPC UA Configuration

Navigate to MOD function → Setup → General → OPC UA → Configuration to view current OPC UA settings.

Document existing settings before making changes

Verify Parent Node References

Check all CfgOpcUaObject and CfgOpcUaPlcVar entries for correct parentNode syntax and existing node IDs in the OPC UA namespace.

Incorrect node references can break entire communication chains

Validate OPC UA Server Namespace

Use OPC UA client tools to browse the server namespace and confirm the parent node exists at the specified path.

Use UAExpert or similar tools to visualize the complete namespace structure

Correct Configuration and Restart

Update the parentNode attribute with the correct node ID and restart the OPC UA service via Setup → General → OPC UA → Service Control.

Service restart will temporarily interrupt OPC UA communications

Check Network Connectivity

Verify Ethernet connection and ping the OPC UA server from TNC Setup → General → Network → Diagnostics.

Check both physical connection and network switch configuration

Verify OPC UA Server Status

Confirm the external OPC UA server is running and accessible via Setup → General → OPC UA → Client Connections.

Server downtime can cause cascading configuration validation failures

Test OPC UA Authentication

Verify security credentials and certificates are properly configured in Setup → General → OPC UA → Security Settings.

Certificate expiration is a common cause of sudden connection failures

Refresh Namespace Cache

Clear and rebuild the OPC UA namespace cache via Setup → General → OPC UA → Advanced → Clear Cache, then restart OPC UA service.

Cache clearing will require reconfiguration of some OPC UA elements

Access Configuration Files

Navigate to TNC file system via Setup → General → File Management and locate OPC UA configuration files in SYS:\OpcUa\ directory.

Always backup configuration files before editing

Validate XML Structure

Check configuration XML files for syntax errors, missing tags, or corrupted parentNode attributes using built-in file editor.

Look for incomplete node ID strings or special characters that may have been corrupted

Restore from Backup

If corruption is found, restore configuration files from the most recent backup via Setup → General → Backup/Restore → Configuration.

Regular automated backups prevent extended downtime from configuration corruption

Rebuild Configuration

If no backup exists, manually recreate OPC UA object and variable configurations through Setup → General → OPC UA → Object Configuration.

Manual recreation is time-intensive and error-prone without proper documentation

Check Server Version Information

Review OPC UA server version and namespace information via Setup → General → OPC UA → Server Information to identify recent changes.

Document namespace versions during initial setup for future reference

Browse Current Namespace

Use Setup → General → OPC UA → Namespace Browser to explore the current server namespace structure and locate moved or renamed nodes.

Namespace changes can affect multiple configured objects simultaneously

Update Node References

Modify CfgOpcUaObject and CfgOpcUaPlcVar configurations to reference the correct parent nodes in the updated namespace structure.

Use namespace index and node identifier format consistently across all configurations

Test Configuration Changes

Validate updated configurations via Setup → General → OPC UA → Diagnostics → Test Configuration before applying to production.

Always test configuration changes in a controlled environment first