Remote access to PXI with DAQmx

[M Schacht]

I have a PXI chassis with an embedded realtime controller (PXI-8186), and some DAQ modules (PXI-6259)x2. I have been programming this via LabWindows with an RT-UI server-client kind of thing using network variables and such. For some applications it would be sufficient, and more convenient to be able to interact with the PXI's DAQ hardware directly from a network connected PC.

The controller runs a VISA server, so it appears I could connect to that from a remote machine with some kind of viOpen("visa://pxi.somewhere.com//PXI0::15:INSTR"); and then communicate with a particular DAQ card. But I can't find any information about programming the 6259 in any way other than DAQmx or similar.

First question then: Is the PXI-6259 VISA interface described anywhere?

More convenient would be to continue to use DAQmx, via something like DAQmxCreateDOChan(taskHandle,"pxi.somewhere.com//Dev1/port0/line0:4",......

I found references to something called "Remote Device Access", for example:

    http://digital.ni.com/public.nsf/allkb/5CC9792C6CD4A34C862565BC0072D5DF

 which seems to implement something equivalent,  but I can't find it where directed to look in MAX:

     Start->All Programs->National Instruments->NI-DAQ->Remote Device Access Server

 and I have seen suggestions that maybe it is only for Traditional DAQ, or only pre 7.0, or in some other way no longer applicable.

Second question: Does "Remote Device Access" still exists and how to I install/enable it on my PXI controller?

Does anyone have any clues about the above, or any other way to get the same sort of functionality?

Thanks,

Mike Schacht

LANL

[Seth_B. · Accepted solution]

Hello Mike,

Remote Device Access was a feature in Traditional NI-DAQ a long while ago.  This functionality was not ported over to NI-DAQmx because the framework that it was built on doesn't really fit well with the modern day need for intense network security.

Unfortunately, the functionality that you describe doesn't exist per say for DAQmx.  Currently, this kind of control is limited to deploying applications to the RT target.  While VISA is used for some portions of the DAQmx interaction, these function calls are not documented.  Someone else on the forums may be able to help if they've tried to implement something like this in the past.

Best of luck!

[M Schacht]

Thanks Seth,

Now everything I have been reading makes sense. I'll keep working the way I have. Though for future reference, is it possible to use an MXI module instead of the embedded controller in any of the PXI chassis' for remote access to the DAQ devices?

Also, how does MAX use the PXI DAQ devices? It there a dedicated server on the PXI controller, the LabView RT runtime?

[Seth_B.]

If you use a MXI connection to a desktop PC, your DAQmx devices will enumerate in MAX just as if they were PCI cards natively in the PC.  Thus, to address them, you would use syntax such as "PXI1Slot1/ai1" instead of "Dev1/ai1", though the "PXI1Slot1" can be renamed in MAX.

If you are using an embedded controller with RT on it, then MAX uses TCP/IP to communicate with the chassis.  If you are using MXI, it's much lower level and for all intents and purposes, the modules in the PXI chassis are handled as though they were in the native PCI slots.

Regards,

[Raul2203]

Hello all,

I am using PXIe1085 as my real time target.

I am trying to read data from my DAQmx card installed in slot 4 of my PXI module.

But, in this process I'm getting this error message 'Waiting for RT- PXI to respond'.

Does anyone have any idea about the reason behind this? And how can this be avoided?

Thanks,

Rahul

Knorr- Bremse Sfs GmbH

Germany

[RikkiTikkiTucker]

Hi Rahul!

To get better help from the community with your issue, I would recommend creating a new forum post.  The thread you have posted on here is 6 years old, and by making a new one, it will be more visible to the community.

Thanks!