GPIB-USB-HS not recognized

[LVKB]

Hi Everyone,

I've been using a GPIB-USB-HS adaptor to communicate with a variety of devices for a few months now, with no problems. But yesterday the device has completely stopped working with my computer. GPIB addresses aren't recognized in LabVIEW, but the adaptor it does show up in MAX (usually). When I do a device scan there, I get the message "There was an error performing the instrument scan." I've run the NI-488 troubleshooting utility test, which the software passes and the hardware fails. The problem seems to be windows not recognizing the GPIB-USB-HS - sometimes (usually) I get a "USB Device Not Recognized" error when connecting the device, but only on this computer (and I've tried every USB port). The several other computers I've connected it to recognized it just fine.

My stetup:

Windows XP SP3

Dell Precision 670 (2 Xeon 2.8GHz CPUs, 1GB RAM, all USB ports USB 2.0)

LabVIEW 8.5.1

NI-488.2 v2.5

I've tried removing every piece of NI software including removing all NI registry keys, then reinstalling, and deleting registry keys in HKLM/SYSTEM/CurrentControlSet/Enum/USB. At the very end of the day yesterday everything suddenly worked, but now it's not working again.

Can anyone guess what the problem is? One thread I looked through mentioned that this device wouldn't work if the USB hub didn't have enough power capacity. Could that be it

Thanks for your help!.

[Dennis_Knutson]

It sounds to me like this is a problem more with the pc than with the GPIB controller. You can opne windows device manager and find the USB Root Hubs listed. The properties of each will how much power is available (should be 500 ma per port) and how much is required for the device that is plugged in. I don't remember how much the USB-HS requires but it's less than the 500 ma available from a working hub. If I remember correctly, it was higher than other USB devices I was using at the time so other devices might not show a problem. I have no idea what could cause all of the hubs to malfunction though.

[LVKB]

I checked the USB hub power information in Device Manager, and for each hub it said there was 500mA available per port. The hub which had the GPIB-USB-HS attached had it listed as using 500mA, and another device using 98mA. Does this mean the GPIB adaptor is using the maximum power? If there was a problem with the power usage, why did it work fine for 2 months before malfunctioning?

The other thing I don't get is why this problem seems to be intermittent - sometimes the device isn't recognized at all, other times it is recognized and installed but doesn't work in MAX or LabVIEW, yet it has worked fine in the past.

Thanks for your help, any more ideas?

[Dennis_Knutson]

What I'm not sure of is whether there is any actual current measurements being taken. In other words, is the 500ma available just something listed because that is what is supposed to be there. If there is an actual problem with the power being provided to the hubs, the full 500ma may not be available. The only way to make sure, would be to place a load on one and measure the current.

Since you've verified that the controller works on other pc's and it was once working, that would indicate to me that either the pc or the driver became broken. Since you've reinstalled the driver, that leaves the pc. Power supplies and voltage regulators do go bad.

[LVKB]

I finally got sick of this problem so I swapped my hard drive into an identical computer that wasn't being used. The GPIB-USB-HS works just fine now, so some part of the old computer's hardware must have failed.

Thanks for your help.

[sjborch]

Just in case this helps someone out there: on our setup, the GPIB-USB-HS was appearing as "USB Device" when plugged into the desktop. We disconnected it from the GPIB end of the instrument, and it was then recognized as GPIB-USB-HS in Windows.

[Code]

Hi, I brought this GPIB-USB-HS cable two years ago. But I didn't start to use it untill today. I was not able to find the contacted scope at all.

I have labview 7.1 and MAX 3.1.1 installed. Is there additional driver required for this cable? 

I will really appreciate a quick reply on this issue as I am using it for emergency programming. Thanks. 

[Dennis_Knutson]

Yes, there are drivers required for the GPIB controller. You need to install NI-488.2 and should also install NI-VISA.

p.s. It's a waste of time to link to pictures that reside on your local C drive. No one can see them. Use the attachment option (right below the message body).

Message Edited by Dennis Knutson on 04-21-2009 08:36 AM