AnsweredAssumed Answered

VISA COM INSTR command return two answers for each instrument

Question asked by oferoded on Dec 21, 2014
I’m writing some API for Keysight scope MSO9404A using C#. My platform is Windows 7 32 bit.
I installed the IOLibSuite_17_0_19013 library using side by side mode because I have another non Kesight instrument connected which uses NI VISA.
My instruments are connected via the USB port.
In my C# project I added a reference to VISA COM 5.2 type library.
I’m using this code to scan for connected instruments:

                ResourceManager resourceManager = new ResourceManager();
                String[] sResources = resourceManager.FindRsrc("?*INSTR");
And I got two answers even if I have one instrument connected:


Please notice that the VID and PID in the address line are the same in the two lines but in different format:
2391 = 0x0957
36877 = 0x900D

I investigated for a while and noticed that in the directory c:\Windows\System32\ I have two dll’s:

When I rename agvisa32.dll to another name and run again my code I got only one line in the answer:

Just to be clear:
The problem occurs only if Kesight Visa is installed as secondary Visa at Side by Side mode.

Any idea how to solve the problem?