Archived:Vision Builder Will Not Connect with CVS After Opening LabVIEW

Updated Jan 12, 2018

National Instruments does not actively maintain this document.

This content provides support for older products and technology, so you may notice outdated links or obsolete information about operating systems or other relevant products.

Reported In


  • Vision Builder for Automated Inspection
  • LabVIEW Full

Issue Details

After opening LabVIEW, when I try to run Vision Builder AI scripts, I get an error saying that the connection failed and that the server may be down. I am able to run Vision Builder scripts before I open LabVIEW and know my CVS is configured properly. Why am I getting this error?


When targeted to the CVS as a real-time target, LabVIEW checks to see which files are currently in memory on the target. If the Vision Builder VIs are in memory, in order for LabVIEW to run, these VIs need to be closed. Closing the VIs will shut down the Vision Builder Server and subsequent calls to Vision Builder on the CVS will fail with the aforementioned connection error. Your CVS will need to be restarted for Vision Builder Server to be reloaded into memory.

If you want to run Vision Builder Scripts on your Compact Vision System from LabVIEW you will need to use ActiveX. There is a shipping example provided with Vision Builder AI demonstrating how to use Active X through LabVIEW to run Vision Builder AI scripts. This example is called “” and can be found at the following location on your hard drive (assuming you have installed Vision Builder in the default location):

C:\Program Files\National Instruments\Vision Builder AI X.X\ActiveX Support\Examples\LabVIEW

It is important to note that the execution target for LabVIEW needs to be set to LabVIEW for Windowsand not to the RT Target corresponding to the CVS.


Not Helpful