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Cannot Read Data from OPC Server with LabVIEW Executable

Updated May 14, 2023

Reported In

Software

  • LabVIEW
  • LabVIEW Datalogging and Supervisory Control Module
  • LabVIEW Datalogging and Supervisory Control Runtime Module

Issue Details

I am using LabVIEW as an OPC client to read values from an OPC server. This works well in my development environment, but when I run my executable on my deployment computer, all the network published shared variables return zero values.

Solution

Confirm the following has been done for your application:

Additional Information

The LabVIEW executable does not automatically deploy the shared variables to the Shared Variable Engine (SVE). As a result, you will have to configure the executable to deploy the variables in the Build Specifications, or deploy them programmatically. 

The NI DSC Module provides the OPC Client I/O servers that connect to each OPC tag using the OPC DA standard. The SVE provides a Publish-Subscribe-Protocol (PSP) URL for each OPC tag that other Shared Variables can bind to by enabling aliasing. Once you deploy the Shared Variables in the SVE and the Shared Variables receive values, LabVIEW can easily read and write to the Shared Variables using a VI. 

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