Although National Instruments has several OPC servers, the control logix is not yet one of them. I would recommend using the RSLinx OEM OPC server and use the Datasocket OPC client to communicate with it. Alternatively, you can add the LabVIEW datalogging and supervisory control module to LabVIEW for a true OPC client.
Thanks for your question
Preston Johnson
Solutions Manager, Industrial IoT: Condition Monitoring and Predictive Analytics
cbt
512 431 2371
preston.johnson@cbtechinc