Instrument Driver for Keysight 34461A DMM works with GPIB, errors with USB

[awooster]

I'm trying to remotely control a Keysight 34461A DMM using the instrument driver located here:

http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=21589

This instrument driver works like a charm when the DMM is connected via GPIB, but it errors out when it is connected via USB.  I've isolated the problem to "Default Instrument Setup.vi".  When this VI is called in the USB case, the instrument is left in a state that results in a timeout of any subsequent call to VISA Read.  The only way I've found to get the instrument talking again after this error condition occurs is a power cycle.  I have another 34461A exhibiting the same behavior, so it is unlikely to be a hardware issue.  I can run the example "Agilent 3446X Series Acquire Single.vi" successfully over USB if I remove any calls to "Default Instrument Setup.vi".

Has anyone else experienced this or a similar issue?

I'm using Windows 7, LabVIEW 2014 SP1, NI-VISA 14.0.1, and the GPIB-USB-HS+ (NI-488.2 14.0) when operating over GPIB.

[mkossmann]

It could still be a bug in the instruments firmware not only a bug in the driver. To decide that, you have to look which commands the driver is sending to the device with NI-IOTrace and check in the instruments programming manual if they are OK.

[jjp377 · Accepted solution]

From the Readme

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3. Known Issues

Agilent IO Suite has to be installed to use USB interface.

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