Why does NI VISA FindResources take 1 minute?

[rickr]

We're running NI VISA 3.2. When we execute GetLocalManager().FindResources("VXI?*INSTR") it takes 1 minute when the PC's DNS & WINS servers are setup. Why is FindResources() querying DNS & WINS Servers? How can I control this behavior?

[JohnM 64]

Hello,

If you have any Remote VISA Systems configured in Measurement and Automation Explorer, and VISA detects that it is connected to a network, it will scan the network to find that remote VISA system.  This could account for the large amount of time you are seeing.  To see if you have any remote systems configured, open Measurement and Automation Explorer, expand the Software entry in the tree on the left, and highlight NI-VISA.  Then move to the right, and click the VISA Options tab at the bottom of the screen.  This will bring up a new window in the area on the right, with a new tree structure.  In this new tree structure, highlight Remote under General Settings.  If there are any remote VISA systems configured, they will show in a box on this screen... and if any have checks in the boxes, deselect these systems.  Then VISA will not search the network for resources when FindResources runs.

Hope this helps!

john m
Applications Engineer

[rickr]

We don't have any remote VISA servers configured, yet FindResources still goes out to the network repeatedly looking for something. Examination of the network packets show the text "crl.thawte.com", as though NI VISA is trying to check licensing or something. If I change the DNS & WINS configuration, removing those servers, the time drops dramatically, to about 12 seconds. Any idea what NI VISA is doing & how we can control it?

[JohnM 64 · Accepted solution]

Hello,

I searched the discussion forums for that file you mentioned, and I found a rather lengthy correspondence between a Measurement Studio employee here at NI and a customer having a similar problem.  It appears that this is a known issue with Microsoft involving any .NET assemblies that are code signed with a digital certificate, as the Measurement Studio assemblies are.  The only workaround offered by Microsoft was the following:

1. Launch Internet Explorer and go to Internet Options

2. Click on the Advanced tab

3. Scroll down to the "Check for publisher's certificate revocation" checkbox and uncheck it.

If you are interested in learning about this issue more in depth, here is a link to the post that describes it in detail.  Have a great day!

john m

[mcfa9597]

I have tried all the help in this thread, and I find that FindResources still takes 6 minutes on my computer.