OMRON NJ/NX OPC UA Configuration Guide

5.2 Status Monitoring

Server Status: When Sysmac Studio is online, check the "Server Status" page to obtain the current status (running, error, closed), the number of connected clients, and the number of users.

Event log: The controller's event log will record OPC UA related errors (such as certificate mismatch, variable count exceeding limit, etc.).

Execution log: A detailed log file stored in the SD card, which records authentication success/failure, variable access details, etc. You can view it through the "Display Operation Log" window of Sysmac Studio or directly on the SD card (file path:/packages/OPCUA_Server/ExecutionLog/).

5.3 Common Errors and Countermeasures

Server certificate mismatch (event code 15020000 hex):

Reason: The IP address of the controller has changed, but the server certificate has not been regenerated.

Solution: Manually regenerate the server certificate and export the new certificate for installation on all clients.

Connection rejected (client in rejection list):

Reason: The client's certificate was not added to the controller's' trusted certificate list '.

Solution: On the client authentication page, move the corresponding certificate from the "Rejected Certificate List" to the "Trusted Certificate List".

Variable cannot be read or written:

Reason: Variable size exceeds 60KB; array starting index is non-zero; Structure nested more than 3 layers; The total number of global variables exceeds the upper limit; Insufficient user role permissions.

Check: Check the execution log for records related to SERVER-0100 or SERVER-0101, and adjust the variable structure or optimize the number of publications according to the prompts.

5.4 Hardware replacement and backup recovery

CPU replacement: Server certificates are hardware related information and are not included in regular backups. After replacing the CPU, even if the backup is imported, the server certificate must be regenerated on the new CPU and the new certificate must be exported and installed on the client.

Backup strategy: The controller backup function of Sysmac Studio can backup OPC UA server settings, client certificates, security policies, etc. But when restoring, you can choose whether to restore the OPC UA security configuration file. Execution logs need to be managed separately as they are stored on an SD card.

Performance considerations and system design

Startup time: The startup time of the OPC UA server (from restart to running state) is related to the number of variables published and the proportion of task execution time. The more variables there are, the slower the startup.

System service execution time: The OPC UA server runs as a system service. If the CPU task cycle is too full, resulting in insufficient system service execution time (reference value below 20%), it will cause OPC UA response delay or timeout. Sufficient time should be reserved for system services when designing tasks.

Online editing: When the OPC UA server is running, it is allowed to add network publishing variables through online editing without restarting the server. The newly added variables will be dynamically added to the address space.