Creating an "IVI session" using COM

Question

I am trying to program NI's RFSG from a COM client with LabVIEW acting as the COM server.
An niRFSG initialization vi requires as one of its inputs a wire of type "resource name (IVI session of class niRFSG)". Passing the resource name as a string (e.g. "pxi1slot2") doesn't work because of type mismatch. Which COM component can I use in my client to create an object of type "resource name" from its human-readable name?
Where is information like this documented?
Thanks!
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Answer 1

Hello f28,
Your assertion that LabVIEW automatically casts the strings passed into the resource input of VIs which use a device’s resource name is correct, and can be noticed by the little red “coercion” dot which appears at that VI’s resource name input terminal. 
So, we must find a way for you to take strings from Python and make them “IVI session of class niRFSG” data type.  I believe that [Class Prefix]_InitWithOptions from the IVI Function Tree would get you the correct data type, but I am not completely sure (possibly something for you to try out).  Unfortunately the C API and LabVIEW API are the only ones that are documented for IVI (unless you also have Measurement Studio for .NET installed).  So, I think that the easiest (and less research-intensive) way of going about this would be to just create other VIs which will convert strings to the appropriate IVI class for you.  Attached is one such VI, which is just composed of a String Control and an IVI Class Session Indicator.  The indicator’s class was selected by right-clicking on in, and selecting Select IVI Class » IviRFSigGen » niRFSG.You could possibly use this VI (and other VIs for other IVI-specific classes) instead of calling directly into the COM component.  It may be a little easier since it looks like you are already calling into VIs in order to use the RFSG driver.  Would this meet the requirements of what you are trying to accomplish?The guide to the IVI documentation should be installed on your machine under Start » Programs » National Instruments » IVI » IVI Driver Help.  Like I mentioned though, nothing about COM in here, but LabVIEW and C instead. Also, you should beware that calling into the RFSG library from LabVIEW will not circumvent the fact that the driver is a 32 bit DLL at its core… In other words, calling it from LabVIEW will not make it a 64 bit application any more than calling the C API… unless I am missing something here…
Chris_G
Sr Test Engineer
Medtronic, Inc.
Attachments:
StringToIVIRFSigGenClass.vi ‏6 KB