Can't install driver for a possible USBTMC instrument

[ssteger]

Hello,

I have a Newport 525B Laser Diode Driver that I would like to communicate with using Labview and NI-VISA on Windows XP.  I have installed the software that came in the box and I was able to successfully communicate with the 525B using an included VI that essentially emulates the front panel of the instrument.

The software also comes with some Labview libraries that appear to use standard VISA blocks for communication.  The libraries do not include all of the instrument's functions, so I would like to be able to write my own libraries.

The manual for the 500B series of instruments can be found here:
http://www.newport.com/file_store/User_Manuals/Model_500B_LDD_Users_Manual.pdf

The manual does not mention a communications protocol, but it does include a section of SCPI commands.  This leads me to believe that it uses USBTMC for communication.  I am currently attempting to verify this directly from Newport.

Unfortunately, the 525B does not show up in NI-MAX when I installed it using the included driver.  If the instrument uses USBTMC, it should be able to use the NI USBTMC driver included with NI-VISA.

I found two NI documents referring to USBTMC:

http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/044fa220f32774ed86256db3005850ca?O...
http://zone.ni.com/devzone/cda/tut/p/id/4478

The first document says to "instruct the [new hardware] wizard to search for the driver, which in this case is NI-VISA."  When I see the list of possible drivers, there is no option for NI-VISA, though there are options for NI-GPIB and NI-IMAQ.

The second document says that "no configuration is necessary to communicate with a USBTMC device."

Last, I found this post on these forums:
http://forums.ni.com/ni/board/message?board.id=170&message.id=261101&query.id=146028#M261101

The users suggest that in their instrument's .inf file, "the class = LibUsbDevices does not look correct for USBTMC."  I looked at my own .inf file that came with the instrument.  It contains "Class=USB" and appears to be from a developer package called EZ USB.  Does this mean that the device is probably not USBTMC compatible?

So, in summary, I have several questions:
1) Is there any method that I can use to determine if the 525B is USBTMC compatible or not?
2) Is there a way to force Windows to use the NI USBTMC driver for this device?  (niusbtmc.inf is located in %SYSTEMROOT%\inf, but it doesn't show up on the list of possible drivers)

Software information:
OS: Windows XP SP3
NI-VISA: 4.6 (latest, NI-MAX reports 4.6.1f0)

Thank you for any help,
Scott

[markus kossmann]

Did you allready check the windows device manager ? If the device uses the standart USBTMC driver it should be listed there as "USB test and measurement device".  If it uses another driver, then should be listed there, too. But you can't expect then that it is seen by MAX.

Do the supplied driver libraries include VI's for "lowlevel communication" , which allow you to send command strings to the device and read the response ? Then you don't need to write your driver from scratch. Just add a wrapper ontop of the existing driver which adds the missing features by sending the command strings with these VI's.  

[Dennis_Knutson]

Why don't you post the VIs that the vendor provided? Just because it uses VISA does not necessarily mean the driver is USBTMC. You should be building on the existing VIs and not starting from scratch.

[ssteger]

Thanks for the replies.

I haven't found a "low-level communications" block in the library yet, but I think that there's a good chance that it could be there.  I'll keep looking.

One of the reasons I was hoping to be able to use the NI USBTMC driver is because it can be used in Matlab.   Only one of our computers has Labview installed on it, but all of them have Matlab.  I guess if I want to use this instrument on other computers, I should go ahead and buy some more Labview licenses.

Also, I'm not sure if I should post the Newport VIs due to copyright/licensing restrictions.  I may if I feel like it could be very useful.

Scott

[Dennis_Knutson]

I don't know what low level communications blocks you are looking for. Originally you said it uses VISA. Does it or doesn't it? If it does, what VISA functions? What VISA Resource Name does it use?

[ssteger]

I'm sorry.  I should have been more clear.  markus kossman, who posted above you, asked me if "the supplied driver libraries include VI's for 'lowlevel communication', which allow you to send command strings to the device and read the response."

I haven't found a VI in the supplied libraries that allows me to do this, but I imagine that there must be one someplace.

I originally said that the supplied libraries used VISA because I see VISA blocks when I look at their code.  Now, though, I notice some custom (text code) functions written in that call one of their DLLs.  I'm beginning to think that I need to give up hope for USBTMC and just use their VIs for communication.

The VISA resource name appears to be generated by an initialization block and I am trying to decipher exactly what its output is.

Scott

[Song_D]

ssteger,

To answer your original question, whether a device is USBTMC or not is determined by the device's firmware.  I would recommend you to use USBView.exe to check the device class and device sub class. An USBTMC device should have 0xFE and 0x03 for those two properties, respectively. If the device is not programmed as a USBTMC, you can't really force Windows to bind the NI USBTMC driver to it.

Looking at the exsting posts you made, I'm fairly sure that the device is not an USBTMC device.  You can always use NI Spy to see if there are any called being made by the vendor provided dll to VISA. It it does use VISA, NI Spy should help you figure out how it constructs the resource name as well.

Message Edited by Song D on 10-29-2009 05:25 PM