USB Interface in LabVIEW Realtime

[Madan]

Hello All,

Here is a little bit about my application.

• I am using IntrpidCS' ValueCAN for HS CAN communication (low cost version of NeoVI). This device is made by IntrepidCS(http://intrepidcs.com/). 
• Interpid provides Drivers and Win32 DLL interface for LabVIEW in Windows environment.
• I am able to communicate to the vehicle over ValueCAN in LabVIEW for Windows.

However, for some precise control loop tuning, I will need to use the same setup in LabVIEW RT. I am using a desktop ETS with LabVIEW 8.5 (Pharlap) as my RT target.

Based on this link (http://intrepidcs.com/support/ICSDocumentation/neoVIDLL/neoFrameMain.htm), I should be able to develop my interfaces. Are there any specific USB interfaces in LabVIEW Realtime 8.5 ? Are there any examples available to get started ?

Thanks!

[Jim_S]

Hello Madan,

I looked at the link that you posted and the notes you provided and these drivers won't work on a Real-Time system. The reason is that these dlls call into Win32 dlls. You can check this by running the DLL Checker. We do have some other drivers that work in a Real-Time OS like NI-CAN, NI-DAQmx, NI-VISA, etc. Since your CAN device is not ours, we would need a driver for Real-Time OS. Using this driver, we could use NI-VISA in order to communicate with the device.

Therefore, at this point I would call Intrepids and ask if they have a Real-Time Driver for this CAN device.

JimS

[Madan]

Hi Jim,

thanks for your reply.

In the same link

http://intrepidcs.com/support/ICSDocumentation/neoVIDLL/neoFrameMain.htm

Under the section RAW API, 

"Normally a custom application will want to access the neoVI via the neoVI DLL. This DLL was written only for Microsoft WIN32 applications. Since not all neoVI applications are for Windows we offer a RAW communications API. "

 How can I access these Raw bytes on the USB port fromLabVIEW Realtime ?

Thanks,

Madan

[Jim_S]

Hello Madan,

You can access the data from a USB RAW port by using NI-VISA. I have found a KnowledgeBase that explains how to do this on the cRIO. In this KB, it states that there are three examples in the example finder for different types of USB communications. I have also found some general information in the LabVIEW help file about USB RAW communication.

JimS

[daniel.white@revoleng.com]

Hi Jim,

Thanks! From the link you posted

"It is possible to use NI-VISA on your CompactRIO controller if your controller is running the VxWorks real-time operating system. Using LabVIEW Real-Time with VxWorks allows for any USB device that doesn't have an associated driver in the Operating System to get attached to VISA by default."

Does it imply that the USB access over VISA is not possible with LabVIEW RT Desktop ETS system or targets with Pharlap?

Thanks

Madan

[G-Money]

Madan,

           In the Related Links section on the KB that Jim linked, was a KB on supported NI-VISA Operating Systems (http://digital.ni.com/public.nsf/allkb/36F14D84EC594D5C8625754B00782629?OpenDocument). This KB lists that the only Real-Time operating system that currently supports NI-VISA for USB communication is VxWorks. It is currently not support on Pharlap targets. 

[Madan]

Grant,

Will this option be available with LabVIEW 2010?

Thanks

Madan

[G-Money]

Madan,

       Not that I know of but you can definitely submit a product suggestion (http://digital.ni.com/applications/psc.nsf/default?OpenForm) and maybe the NI-VISA driver team can add it to 2010 because the bottleneck is just support from the driver itself.