VB Programmer looking to LabView

[GlennPiper]

I am an experienced Visual Basic programmer, and am learning LabVIEW. I am interested in using LabVIEW for data acquisition and analysis in an upcoming project because of its pre-packaged components that will hopefully save me development time and run faster than if I did it all in VB. I don't want to write the entire app in LabVIEW because I am still very new to it, and need to leverage my VB knowledge to be able to complete the project on time.

I had planned on writing VIs to handle instrumentation control and possibly some data analysis, and build them as DLLs to call from a Visual Basic 6 app. However, I am currently using the 6.1 Full Development System and it appears that I need the Professional Development System to do this.


So, a few questions:
1) I understand I can call LabVIEW as an ActiveX application and have it load and run a VI, but can I easily pass and receive data to/from the VI?
2) Can I do this with just the runtime installed? (I don't want to force my users to have to buy the full LabVIEW package to run this project.)
3) Is there a speed hit over using a DLL?
4) Are there any other options without upgrading my version of LabVIEW?
5) How does the speed of a DLL compare to a native VI? I assume it is comparable, but have not been able to test that yet...
6) What new options open up if I purchase LabView 7?
(As far as this automation stuff is concerned, that is. I am not using .NET yet, so that is not a big plus to me at the moment, however if it has good XML support, that would be nice.)

I am interested in any other opinions or thoughts from the LabVIEW masters!

Thanks!

Glenn Piper

[Greg_McKaskle2]

> 1) I understand I can call LabVIEW as an ActiveX application and have
> it load and run a VI, but can I easily pass and receive data to/from
> the VI?

Yes. There are examples that show how.

> 2) Can I do this with just the runtime installed? (I don't want to
> force my users to have to buy the full LabVIEW package to run this
> project.)

In order for your VIs to be used by others you need the Professional or
they need LV.

> 3) Is there a speed hit over using a DLL?

If you have two processes, COM is slower due to data transfer between
apps. If they are in the same process, COM is faster, and using DLLs,
it is still faster since they pass more pointers and the data isn't
being converted between as many types. If you aren't talking about
megabyt
es of data, though, then the cost should be minimal.

> 4) Are there any other options without upgrading my version of
> LabVIEW?

NI also sells VB components which adds DAQ and analysis and display
functionality to VB. I'm not sure what the licensing is in using these
controls on multiple computers.

> 5) How does the speed of a DLL compare to a native VI? I assume it is
> comparable, but have not been able to test that yet...

The DLL internally calls the native VI. It has to go through a proxy to
get the C information into what we call a dataspace, but it is comparable.

> 6) What new options open up if I purchase LabView 7?
> (As far as this automation stuff is concerned, that is. I am not using
> NET yet, so that is not a big plus to me at the moment, however if it
> has good XML support, that would be nice.)

It does include some XML support, but I'm not sure it has anything new
over 6.1. ActiveX should be the same with some bug fixes, and .net
client support is added. T
here are lots of other features, but not
necessarily in the VB connectivity area.

Greg McKaskle