visa usb bulk communication - multiple end points

[gharris]

Hi All,

I'm setting up an ocean optics USB2000+ spectrometer and would like to use visa instead of the dll I got with the spectrometer (I had a bunch of stability problems, its not supported anymore by ocean optics and I don't want to have to pay for the new version).  I have the documentation for the spectrometer and have been able to set the integration time and receive spectra as quickly as the dll was able to.  But I have not been able to read the calibration information from the spectrometer.  All commands use bulk transfer, so I'm using visa write and read to send/receive.  I think the difference between the spectral data and calibration data is that the data comes from different endpoints.   The spectrometer has 4 endpoint addresses (3 to the PC = IN, 1 from the PC = OUT).  The spectral data comes back on the first IN endpoint and the calibration data comes back on the 3rd IN.  

Is there a setting I need to change to read from a different endpoint?  They are all bulk type according to the documentation.  Any suggestions would be much appreciated.

thanks!

[Justin_E]

Hey gharris,

I'm going to have to research into this a bit more before I can provide you with any suggestions. Thanks!

[gharris]

Thats great - thanks for your help.  I'd be happy to provide any vis I've written.  Most of Ocean Optics documentation is password protected, so they probably don't want me sharing it, but I do have the manual for the spectrometer, which is not password protected.

[Justin_E · Accepted solution]

Hey gharris,

It looks like there is a setting you can change through a property node that will change which endpoint you read from. If you're using a text-based program, the property you need to change is VI_ATTR_USB_BULK_IN_PIPE. If you're using LabVIEW, follow these steps :

First, set a VISA property node down on your block diagram (really any property node will work). Next, right-click on the property node and select Select Class -> VISA -> I/O Session -> USB Raw. This step can be found in EndpointSS1.png attached below, and will change the property node to a USB Raw property node. Third, left-click on Property and select USB Settings -> Bulk-In Pipe. This step can be found in EndpointSS2.png, attached below. This is the property that sets which endpoint to read from. To change the value of this, right-click on the property node and select Change all to Write, which will allow you to wire in an endpoint value. 

[gharris]

Hi Justin,

Nice work!  Thats exactly what I needed.  I've always had better luck using Visa than most vendor's drivers.  This is another great example of how well it works.

thanks,

George

[MSD100]

Can you post your VI having Multiple endpoints supported for bulk transfer?

[gharris]

Are you looking for USB2000 software? Or is your question more general?  For the spectrometer, most of the reads were from one endpoint so I left the endpoint value set for that one.  Once in a while I'd change the endpoint, do a read and then change is back.  Here's an example:

[MSD100]

Thanks for the reply..I am working with usb raw interrupt and bulk communication between uC and labview....my controller supports 5 different endpoints atleast 64 bytes long in or out pipes..so I want to know how to write program in labview so it can read or write all the data from all endpoints from controller....

I have posted one question regarding my vi...posted here..http://forums.ni.com/ni/board/message?board.id=170&thread.id=469273

can you help me out in this vi for multiple endpoint support?