Error -1950679035 When Programmatically Changing Shared Variable Properties

Updated Oct 29, 2018

Reported In

Software

  • LabVIEW Full

Issue Details

When programmatically changing properties of a deployed Shared Variable with a Property Node (using the SharedVariableIO class), I receive the following error:

Error -1950679035 Occurred at ni_tagger_lv_read

Possible Reasons: The shared variable does not exist

Solution

You may get this error if you attempt to write to the SharedVariableIO property node too frequently. See the Additional Information section for details on why the error occurs. The best way to prevent this error is to use event-based programming instead of writing to the Shared Variable inside of a loop. 

Additional Information

When a property change is made to a Shared Variable in the Shared Variable Engine, the Shared Variable becomes temporarily inactive. If you attempt to write to the shared variable at this time, this error can result.

Additional suggestions to prevent errors when writing to a Shared Variable property include: 

  • Use a DataSocket Write to write to the Shared Variable property rather than using the SharedVariableIO Property Node. 
    •  Using the Property Node forces an update to the intermediate Shared Variable Refnum property map. This propagates changes to the Shared Variable Engine, whereas using the DataSocket API writes the new value directly to the Shared Variable Engine. 

      An example of the URL for the Hi alarm level property would be \\localhost\process name\variable name.Alarms.Hi.level.
  • Use appropriate error handling on Shared Variable Reference Nodes rather than letting the VI handle errors automatically, as automatic error handling will stop your VI if an error occurs.

WAS THIS ARTICLE HELPFUL?

Not Helpful