NI-VISA USB Devices

[lmtis]

I am having a couple of problems using a USB RAW device.  I have an interface module that has a PIC18F1450 micro to provide USB communications.  I used the driver wizard to configure it for LabVIEW.  The developer of the module provided a simple VB GUI, and after I used the wizard, the VB GUI could no longer see the module.  If I move it to a different USB port the VB GUI can see it, but LabVIEW can't.  Using a USB device monitor I see that when it is plugged into the port that it was in when I ran the wizard, it shows up as a NI-VISA USB Device.  When I plug it into another port it shows up as a USB Human Interface Device.  Why does the NI software have to change how the device registers in Windows?  Also, when I first connect the module and start my program, I typically have to try communicating with it a dozen times or so before I have any success.  After that, every attempt is successful.  Here is my communication code.

[Mark_Yedinak]

The switch has to mostly with Windows device drviers. A device in Windows may only have one driver assigned to it. I have not seen the type of behaviour you are seeing where your device is exxentially locked to a specific port. We use VISA USB to communicate with printers all the time. What we have found is that once we assign the NI drvier, other tools that require a drvier can no longer communicate with the printer. Likewise if we install some other tool the NI VISA drivers can no longer communicate with the printer. We also use a .dll to effectively install the driver for the printer when it is first connected. This is the .dll example NI provided me when I was first getting this to work with our printers.

We do a VISA resource lookup to get to the list of devices currently connected.