visa32.dll Matlab direct entry

[Brian_Bidwell]

Don't see why one should need Matlab insturment control toolbox when the Visa32.dll should be able to be called and used in Matlab directly.  Help start this off please.

loadlibrary('C:\WINDOWS\system32\visa32.dll','C:\Program Files\IVI Foundation\VISA\WinNT\include\visa.h','alias','visa32');

not sure what to do with defaultRm

Must be something like

calllib('visa32', 'viOpenDefaultRM', defaultRm)

calllib('visa32', 'viOpen', defaultRm, 'GPIB0::22::INSTR', 0,0, vi)

Can't figure it out and need help from a matlab and C guru.  Shouldn't be hard for someone that knows matlab and C real well.

[TV_Enable]

Hi Brian,

I don't know to call the DLL from MATLAB, but you should be able to run C code from MATLAB.  There all several C examples that ship with VISA that you may want to take a look at.  They use the C API for NI-VISA, they don't call into the DLL directly.

Regards,

Todd V

[Brian_Bidwell]

Yes I know about c and Matlab.  Doesn't work for for two reasons.  1) C requires MexFunctions (yuck)  2) Matlab changes how the Mex Functions work sometimes between versions.

I feel that Direct DLL calls are the only sensible way to do this.  I know it is possible because I've seen it done with straight GPIB.  For example see the link below

http://code.google.com/p/ni-gpib-matlab-wrappers/wiki/dll_loading

I want to do the same with VISA but there are some C to matlab topics I am not sure I understand.  I know that somone out there who knows C & matlab can help me a little here.

I can almost get a session open.  I watch it in Ni-Spy.

Message Edited by Brian Bidwell on 02-25-2010 04:52 PM

[TV_Enable]

Hi Brian,

I would recommend posting to a MATLAB forum for this issue.  Hopefully someone can help you on this here, but you can probably get more help on using MATLAB on their forums.

Regards,

Todd V