USB communication failed via MAX but not via ACE

[Dennis_Knutson]

The agilent i/o library is required for an agilent GPIB - not ace, as far as I know. In any case, what version of the agilent i/o library are you using and what version of NI-VISA?

You still have not mentioned what programming language you are using. Is it just a problem with MAX you are having or can't you communicate to the instrument in your program either?

[cdux]

Yes that is true. The IO library provides the driver but ACE allows me to see and interact with the devices connected via the USB/GPIB adapter. I have version 16.1 and NI-VISA 4.2. I am controlling my test automation using TestStand with LabView as my main programming language. Since MAX failed to communicate with the device, the VISA scheme is useless for interaction even though I was able to communicate with the devices using ACE's IO GPIB control panel.

I did a bit more research and found two alternative methods which may or may not work pending on my trying out the solutions from previous members that took a while to dug up. One member suggests it was an issue of the Windows 32-bit and 64-bit difference. I have downloaded the latest version of NI-VISA 5.2 with 64-bit and try if that works. The second member suggests that the reference on Device Manager needs be changed to refer the correct .sys file to warrant the conflict. I shall try that next.

If you have any other suggestions that would be great. Thanks.

[Dennis_Knutson]

So are you saying that you cannot communicate to the GPIB modules either with MAX?

[cdux]

That is correct. I cannot communicate to the driver with MAX but am able to with ACE despite the Conflict Manager setting NI-VISA as primary.

[Dennis_Knutson]

Okay, that's different than your original posting where you said you were just having problems with the USB instrument and did not mention the GPIB.

[cdux]

See attachment to illustrate the problem. NI conflict manager, no such errors occurred, but according to ACE's conflict manager the diagnostic are a bit more thorough. Please advise to go from here. Thanks.

[cdux]

Update:

I had to uninstall then reinstall NI Software for one reason or other and monitored the process. This time around, I was able to have ACE recognize through their VISA 32 the same resources and Aliases created both via ACE and MAX. However, the ACE VISA 64 Conflict Manager could not see the devices available even though VISA 32 was able to identify them. As for MAX, all the devices and were recognized. However, as I can input all program code via ACE to all the devices connected to GPIB and USB, I was not able to do so via MAX for USB devices.

To be less verbose, here's a chart:

                                  connection scheme                         ACE IO Test Panel              MAX Open VISA Session

---

HP 6624A PS                 USB/GPIB                                          yes                                                   yes

U2653A  DIO                   USB                                                    yes                                                   no

Any ideas how to fix this? It still doesn't make any sense why I can't communicate with it via NI-VISA.

[MilanR]

Hi cdux,

You mentioned earlier that you were going to verify the USBTMC sys file that was being loaded by the USB U2653A device. It is possible that if a different USBTMC driver is being used that it may not be compatible with MAX, etc. In addition, have you tried the U2653A on a different computer that does not have the Agilent drivers installed (only the NI drivers) to see if the device will function properly using the USBTMC driver and VISA software supplied by NI?

[cdux · Accepted solution]

After verifying that both sees the device and that ACE can communicate with it, I was able to use DAQmx protocol to communicate via LabView as well. However, using direct VISA still does not work. Perhaps this is just a quirk of the instrument.

Thanks for the help.