Communication with USB interface

[RNS]

Dear Freinds,

I need a help if possible.

I am trying to use the labview to control an external device; I want to use the labview to turn on an external device by using the USB port, and after that, the device will do certain processing and then send a data to labview through the USB port. Then, the labview will read this data and draw certain graphs and other analysing.

This is in general what i want to do.

I do not have any DAQ system, because all the processing will done in the external device and the output of this device could be digital or analog, but i do not know which i should select to transfer data to labview by USB.

I know that i am new and also beginner in labview programing but i really need a help to be able to complete by project.

So, if possible, please send me any method or example to help me.

Thanks a lot,

[Dennis_Knutson]

Is this "external device" something you've created or a device you purchased? If it's your own creation, then you can use VISA and USB RAW to communicate with it. There's information at http://zone.ni.com/devzone/conceptd.nsf/webmain/6792bab18242082786256dd7006b6416?OpenDocument on how to use the Instrument Driver Wizard and USB RAW. If this is a commercial device that you bought, you should really be using whatever software the vendor provided. This might be a dll or ActiveX control. If purchased, what is the make and model?

[RNS]

Dear Freind,

Thank you very much. Actually my device, which i want to communicate with it through USB, is a self-made. It contains a microprocess and when i send special code from labview through usb, the process, in the device, will recognize this code and start working. After certain time, the device will start sending the information to labview to draw certain curves and make some processing.

In your reply, you advice me to use VISA, actually i do not know if i have this function module or not; and if i have it, i do not know how to use it.

Please, if possible, can you guide me to solve this problem.

Thanks a lot.

[Dennis_Knutson]

NI-VISA is included with the LabVIEW distribution. You'll find in on your driver's CD. The link I provided has the information you need to get started. Since it's your own device, you could also create a windows dll that interfaces to the device. You would then use the Call Library Node Function in LabVIEW.