Shared Variables Don't Update on Client Side in NI-OPC Servers

Updated Jul 25, 2023

Reported In

Software

OPC Servers
LabVIEW Datalogging and Supervisory Control Module
LabVIEW

Operating System

Windows

Issue Details

I had a working NI-OPC application that was working fine, but is no longer functioning. I have not made any changes to the code. The OPC Quick Client on the server side shows the correct variable values, but when I read the same variables on the client side in the NI Distributed System Manager, the variable values are either all zero or do not show up at all. How can I troubleshoot this issue?

Solution

This issue has been seen with a recent Windows 10 update (KB4056892) that affected the necessary DCOM settings to connect a server and client PC using NI-OPC Servers. This issue was resolved in Windows 10 update KB4058258. Make sure that you have the latest Windows updates installed on your machine.

If the problem persists, there are a few troubleshooting steps to try:

Verify that you are running your application on LabVIEW 32-Bit version.
Ensure that you have deployed the shared variables from the LabVIEW project.
Make sure that your DCOM settings are properly configured.
Try restarting the Shared Variable Engine as an administrator.
Check the OPC Quick Client on the server PC and make sure that the shared variables show up.
Make sure your firewalls and antivirus software are turned off or configured to allow NI hardware and software .

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