Why Can I Connect to My OPC Server in Quick Client but Not With a DataSocket Client?

Updated Dec 4, 2018

Reported In

Software

  • OPC Servers
  • LabVIEW

Issue Details

I can connect to my OPC Server using the NI OPC Quick Client, but when I try to connect using a DataSocket Client, I get Error 1184 occurred at Datasocket Read in MyProgram.vi.
Why does this happen?

Solution

The OPC Foundation has released three major versions of the OPC specification: Versions 1.0, 2.x, and 3.0. The LabVIEW DataSocket API is only compatible with OPC DA Specification versions 1.0 and 2.x. The NI OPC Quick Client, bundled with NI OPC Servers, is compatible with OPC DA Specification versions 1.0, 2.x, and 3.0. If the LabVIEW DataSocket API cannot connect to the OPC server, but NI OPC Quick Client can, the OPC server is most likely operating under the OPC DA Specification Version 3.0.
 
Some servers allow for the operational OPC DA Specification to be changed while others allow for multiple specifications to be used at the same time. Consult with the documentation of your OPC server to determine what OPC DA specification it is operating under and how to change it.
 
The LabVIEW Datalogging and Supervisory Control (DSC) Module includes features that allows it to interface with the OPC DA Specification versions 2.x and 3.0 as an OPC client. If changing the specification the server is operating under is not a possibility, consider purchasing the LabVIEW DSC module to interface with OPC servers operating under the OPC DA Specification version 3.0.