Unknown Variable Values in OPC Quick Client

Updated Sep 29, 2022

Reported In


  • OPC Servers


OPC Quick Client

Issue Details

I configured my PLC in NI OPC Server, but when I connect to it from the Quick Client, my variables have no readings or unknown values. My PLC responds to a network ping so I know it can be reached over the network. Where can I find PLC specific information to troubleshoot my PLC configuration?


You can find PLC specific help in NI OPC Servers by going to Help >> Driver Help and selecting the driver of the PLC you are using. If the connection problem persists after ensuring the configuration of the device and variables syntax matches the help information, contact NI Support for further assistance.