Issue Details

I am using shared variables bound to OPC tags. I am receiving Error -1950679035: Unable to locate variable in the Shared Variable Engine.  

Solution

Below are solutions for different causes of this error:

Shared Variables are Not Deployed 

• Manually deploy the shared variable library 

1. Right click the shared variable library in the LabVIEW project. 
2. Select Deploy. 

• Programmatically deploy the shared variable library

Blocked Access from DCOM and/or Firewall 

• Follow the instructions in Using OPC via DCOM with Microsoft Windows XP Service Pack 2. 

 

Port Conflict with the OPC Server

1. Navigate to Start >> Run on the Windows taskbar. Enter services.msc. 
2. Search for the service that relates to your OPC server and note if it starts automatically. 
3. Select the service and select Stop. 
4. Test if your shared variables will deploy. 
5. Double click on the service and set the startup to Manual to prevent the service from starting automatically. 

 

Using Dual Network Interface Cards

1. Open the LabVIEW project file and right click on My Computer,  then select Properties.
2. Put a check on 'Specify custom address' and enter the secondary NIC address into the Address.

NI OPC Servers Software Is Not Licensed

Navigate to the NI License Manager and verify if the NI OPC Servers software is licensed. The NI OPC Servers is individually licensed and is not part of the LabVIEW Datalogging and Supervisory Control (DSC) Module. For more information about the available licenses, please refer to NI OPC Server Licensing.

Additional Information

Shared Variables are Not Deployed 

If the shared variable library has already been deployed to your host or target computer, you should be able to view it in Distributed Systems Manager for LabVIEW 8.6 or later, or in Variable Manager for LabVIEW 8.5 or earlier. 

Programmatically deploying the shared variable library using an invoke node is not supported on real-time targets. However, you can use the invoke node on a host computer and target the real-time target with the "Target IP Address" input option. 
 

Blocked Access from DCOM and/or Firewall 

DCOM and/or Firewall settings can prevent your computer from accessing individual variables in the Shared Variable Engine. They can block specific ports that prevents the Shared Variable Engine from using the OPC Server to pass information. 
 

Incorrect Bound Shared Variable Paths 

Install the LabVIEW 8.6.1 Shared Variable Patch if you are using LabVIEW 8.6.1. You will also need to install the patch on target machines running an executable using the LabVIEW 8.6.1 Run-Time Engine.