VISA Open Exclusive Lock Is Locking The Wrong Resource

Updated Apr 17, 2018

Reported In


  • NI-VISA 14.0
  • NI-VISA 15.5


Newport PSD9 Beam Detector

Issue Details

In my program, I open a VISA resource, Comm 4,  with an exclusive lock to compile a list of resources, I close Comm 4, and then open Comm 4 again with an exclusive lock. At this point, if I repeat the first step of compiling the list of VISA resources, a different resource than the one I locked, Comm 6, is missing. Comm 6 was on the original list. Comm 4, however, shows up as available.


Update your VISA driver to the most recent version, as this has been seen to occur in VISA versions 15.5 and previous. If the behavior persists, please contact National Instruments at 1-866-275-6964.


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