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Using VISA Find Resource for PXI Devices


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I'm using VISA Find Resource to determine what's on my system at the startup of my software. I've been successful using it for just about everything we have in the lab that isn't Ethernet, including recently with some PXI devices (we hadn't started using PXI systems in our lab specifically until just a few months ago with my current project).

I have a Pickering Switch PXI card, an NI PXIe-4353 (Thermocouples card) and NI PXIe-4080 (DMM). The first two show up fine using the VISA Find Resource (with "?*INSTR" as the expression), once I configure NI-VISA in MAX to "Show all devices accessible to VISA" under "PXI/PCI Interfaces". But the PXIe-4080 does not. I had loaned a PXI-4071 DMM (an older NI model), and that one shows up fine.

When we contacted NI support, they were initially confused, as if using VISA Find Resources for PXI devices was super weird or unheard of. Then they tried to claim that since the PXI 408x is completely a different product than the 407x under the hood, it cannot support VISA. We're not trying to take measurements over VISA, just find it, and get some interface information about it (we then plan on using the NI-DMM IVI). I've included a snapshot of a conglomeration of the functionality that we use to find, get information on, and then convert the VISA reference to the NI-DMM IVI ref specifically.

Again, all this worked with the NI PXI-4071 DMM, but I have two NI PXIe-4080 DMMs now that both will not even show up in VISA in MAX. Has anyone else had this issue, or issues like this? It's totally reasonable to use VISA Find Resource for PXI devices, right?

VISA Find to NI-DMM IVI.png

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Posted (edited)

I have read that manual, yes. We have also already tried re-installing NI-DMM, and tried my chassis connected to two (very different) PCs with no change in results.

I need to clarify about what I meant by "once I configure NI-VISA in MAX" the "PXIe-4080 does not" show up.

Both the 4071 and 4080 show up in MAX, but only the 4071 is found by VISA. NI-MAX (or the NI-DMM driver) doesn't seem to assign a Resource/Alias for the PXIe-4080. That's the issue. I can use the NI-DMM softpanel on all of the DMM models fine, and select all of the DMM models using the "DMM IVI I/O" control, but I CANNOT find JUST the 408x model with NI-VISA.

I've attached a few more screenshots showing what MAX looks like on my setup with the PXIe-4080, and an older setup with a PXI-4065 DMM (which is found with VISA just fine). Hopefully that clarifies.

VISA Properties Tab on PXI-4065.png

VISA Properties Tab not on PXIe-4080.png

VISA List of Resources in MAX, no PXIe-4080.png

Edited by YavannaKementari
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Posted (edited)
On 4/15/2022 at 1:26 PM, ShaunR said:

Is it an MXI controller?

I just noticed you had asked this question as well Shaun. Thanks for your quick response.

Yes, our PC is interfacing with a PXIe-1073 Chassis using a PCIe-8361 MXI card via an MXI x1 cable (the little DSUB one). The PXIe-1073 has the "baked in" MXI interface, since we always plan on these PXI chassis being remotely connected to a Windows PC.

Edited by YavannaKementari
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On 4/18/2022 at 6:04 PM, YavannaKementari said:

I just noticed you had asked this question as well Shaun. Thanks for your quick response.

Yes, our PC is interfacing with a PXIe-1073 Chassis using a PCIe-8361 MXI card via an MXI x1 cable (the little DSUB one). The PXIe-1073 has the "baked in" MXI interface, since we always plan on these PXI chassis being remotely connected to a Windows PC.

Well. Assuming you have enabled the bridge (last line of the troubleshooting in the manual) have you tried adding the alias manually?

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Posted (edited)
23 hours ago, ShaunR said:

Well. Assuming you have enabled the bridge (last line of the troubleshooting in the manual)

All PCI-to-PCI Bridges (there are several on the current PC setup) are working an enabled. Again, I can use the DMM cards just fine via their NI-DMM softpanel or the IVI niDMM type session, just not VISA itself.

23 hours ago, ShaunR said:

have you tried adding the alias manually?

As you can see from my second post, there is no VISA properties tab for the DMM PXIe-4080 to even set an alias manually, unless you know of a different way of setting one up?

On 4/15/2022 at 1:45 PM, YavannaKementari said:

VISA Properties Tab not on PXIe-4080.png

Edited by YavannaKementari
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NI Support is still firm with me that "they are no long using VISA to enumerate these devices" (their words). That's pretty concerning that PXI cards made by NI, to a standard they're supportive of (PXI), doesn't comply with VISA at all. I have a meeting with them tomorrow...

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1 hour ago, YavannaKementari said:

unless you know of a different way of setting one up?

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019LgySAE

1 hour ago, YavannaKementari said:

NI Support is still firm with me that "they are no long using VISA to enumerate these devices" (their words). That's pretty concerning that PXI cards made by NI, to a standard they're supportive of (PXI), doesn't comply with VISA at all. I have a meeting with them tomorrow...

Nothing is mentioned in the application note.

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I am probably going to get my details a bit mixed up here, but I ran into something quite similar to this last year.

I think we were trying to either export a MAX config (or programatically reimport it or something) and it did not include our 408x based PXI cards. The official response from NI was that the System Configuration API does not support these cards! I will dig through my email tomorrow when I am back at my work PC.

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Shaun, thank you for that app note - it will be more good ammo for me for my discussion with R&D today.

I'm also going to be referring them to the PXI standard, particularly PXI-2 Software Specification Rev. 2.6, Section 3.2 where it specifies support for VISA for PXI modules. (NI is a "Sponsor Member" of the PXI Systems Alliance)

We did just try manually adding a VISA Alias to the visaconf.ini file. It worked for the PXIe-4353 card (which already works and has a VISA Properties tab in MAX), but it did not work for the PXIe-4080 DMM card, which does not have a VISA Properties tab in MAX.

Here's what we added to the INI file:

[ALIASES]
NumAliases=2
Alias0="'Jimmy','PXI21::0::INSTR'"
Alias1="'Jimmy1','PXI19::0::INSTR'"

 

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  • 4 weeks later...
Posted (edited)

Just so everyone is aware of what the conclusion of this was, and thank you everyone for your help here. 

After lots of discussion with our NI rep and R&D, it was determined that R&D purposefully did NOT implement any VISA capabilities for the NI PXIe-4080 DMM, even the ability to enumerate the device.

They recommended these two things, neither of which are good options for our architecture or requirements:

  1. Use NI's proprietary System Config API to dynamically find the PXIe-4080 DMM. I don't want to transfer my entire framework to this proprietary approach (nor do I believe it would cover all the bases VISA Find does). That's what a standard like VISA is for, which any PXI device should support (at least VISA enumeration/find).
  2. Create an INI/INF file using the VISA Wizard (https://www.ni.com/docs/en-US/bundle/ni-visa/page/ni-visa/usingddwtoprogrampxipcidevice.html), however I don't have access to a Certificate Authority (CA) to make that installable on Win10, nor can I even install the Windows Driver Kit (WDK) on my machine due to IT Security restrictions without particularly difficult approval. NI R&D refused to do the (relatively small) work to create this set of files to fix this oversight.

So at the end of the day, this PXIe device is not VISA capable at all, and they designed it that way. Our project is moving to swap what PXIe-4080 cards we already have to PXI-4070s (which do support VISA enumeration/find/etc.), and future PXI DMM purchases for our setups will likely be Keysight M918xA's, assuming they play nice with NI-VISA on an NI PXI chassis.

I wanted to let folks know that this model isn't fully compliant to the PXI standard (although they tried to claim that they meet the letter of the requirements in a particularly lawyerly way, but certainly not the way any NI customer would read it), and I'm a bit concerned this may be the case with future cards - be aware with NI PXI devices that they might not support VISA anymore.

Edited by YavannaKementari
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