Process nimxs.exe automatically calling VISA::viFindRsrc.

[RyanBichler]

The process nimxs.exe running in the background is automatically calling VISA::viFindRsrc every time the device I am testing is connected to my computer. The device is connected as a network adapter. This process is finding miscellaneous equipment on the network and taking up to 15 seconds to complete each time. During this time it is frequently locking the resource I'm trying to send commands to with Labview and causing the following error.

VISA: (HEX 0xBFFF000F) Specified type of lock cannot be obtained, or specified operation cannot be performed, because the resource is locked.

This behavior started when I updated NI-VISA  from 4.1 to 5.1.1. Is there a way to turn off this automatic search for equipment on the network? The only time I would want to search for equipment is when I open NI-MAX.

[chaka1234]

Hello RyanBichler,

Please open MAX and go to Tools>>NI-VISA>>VISA Options. Then, go to My System>>General Settings>>Remote. You can configure VISA to search resources stated on the list. 

Regards,

Carmen C.

[Alisha_P]

Hi Ryan,

Could you provide some more information about the device you are testing? Is it a VXI-11 device or LXI or something totally different? Does it support auto discovery? Also, what miscellaneous equipment on the network is being found?

It may be helpful if you provide an I/O trace when VISA::viFindRsrc is being called. This trace will provide us a view of all the low-level calls that VISA is making. To do so,

1) Open NI IO Trace

2) Select Tools>Options

3) Select the Logging tab and check "Log to File" and choose what file path you would like to log to.

4) Select the View Selection tab and check everything except LabVIEW (having LabVIEW unchecked will let us see more low level calls)

5) Click OK at the bottom to close out the Options.

6) While you expect this automatic call to VISA::viFindRsrc, click the green arrow to begin taking the trace.

7) Click the red dot to stop when you're done.

Reply with the trace attaced and I'll take a look at it.

Also let us know if Carmen's suggestion allows you to block the extra calls to FindRsrc.

[RyanBichler]

Attached is the I/O Trace.

The device I'm testing is a Motorola radio connected via USB. Attached is a screenshot of it in the Device Manager. I'm using a power supply controlled via GPIB on my local computer to power the device and take current measurements. Any other equipment that is being found on the network by NI-MAX is irrelevant for my application.

I have not tried Carmen's suggestion yet.

Thanks!

[Alisha_P]

Hi Ryan,

I apologize that it  has been so long since I have responded. Are you still having trouble with this? 

Were you able to try Carmen's suggestion?

I've been looking through the I/O Trace and I can see that a general search for GPIB items and I can see where you are erroring out on the write.

I was curious what evidence you found that tied the general search to the mxs process. Could you provide that evidence as well?

[RyanBichler]

The ProcessID 0x00000828 associated with the VISA::viFindRsrc in the IO Trace matches nimxs.exe in the Windows Task Manager. Also, I originally debugged the problem using Agilent IO Monitor which lists the program that makes the call.

As for Carmen's suggestion, there are no Remote Systems in the list to choose from.

[Alisha_P]

Hey Ryan,

From the IO Trace, we can see that something is causing a full refresh to look for any type of system available on the system (as opposed to a partial refresh that we would normally expect to happen when a USB device is plugged in).

There are only a few things that can cause this full refresh, including refreshing MAX and having any changes made to the visaconfig.ini file.

We are wondering if perhaps the creation of a new network adapter that occurs when you plug in your USB device is triggering one of these things (and I will be doing some further testing on this).

One thing that makes changes to the visaconfig.ini file and is associated with searching for things over networks is the LXI Discovery Service. Therefore, it would be helpful to remove that as a possibility. Could you disable that service on your computer and make sure that this still occurs? (you do not need this service unless you are using LXI devices which communicate over TCP)

[RyanBichler]

I no longer see the issue after turning off the National Instruments LXI Discovery Service. The issue returns if I turn the service back on.

[Alisha_P · Accepted solution]

Hey Ryan,

Is it a problem for you to have the service turned off? You shouldn't need it unless you want to be able to automatically discover LXI devices on the network.

We will continue to investigate the issue here and evaluated fixes for future releases.

[Dennis_Knutson]

Isn't the auto scan part of the LXI spec. I would think turning it off is appropriate and the behavior when it is on is normal and expected.