Voltage Measure, detection fail

[Duplessis]

Hello everybody

I'm a new user of Labview and I'm trying to measure a voltage but faced some troubles.

I'm using:

-Labview ver 8.0 on Windows XP

-A basic electric circuit with a tension generator and a resistance to get the voltage

-A SCB 68 connection block

-A NI PXI 1042 Chassis

But Labview seems unable to detect my aquisition circuit, i've tried to use  the DAQ assistant>Analogic entry>Voltage  in my new VI but it didn't detect any device.

Have I miss any points?

Any help would be welcome, if my explanation are not clear enough, you can ask me some more questions.

Thank you for reading my post.

[GerdW]

Hi Duplessis,

Have I miss any points?

Well, you have a PXI chassis and a connection block. You miss the DAQ device in between those two…

[Duplessis]

Thanks for the answer but I forgot to mention that i have a 7831R as a DAQ card and a PXI 8331connection to the computer.

[GerdW]

HI Duplessis,

did you check your DAQ hardware with MAX (Measurement & Automation Explorer)? Is your PXI system listed properly?

(Does your LabVIEW/DAQmx version even support that hardware?)

[Duplessis]

Thank yo agine for your quick answer.

I think MAX do not even detect my PXI, here is a screenshot

http://image.noelshack.com/fichiers/2015/27/1435926315-pxi.png

[GerdW]

Hi Duplessis,

please attach images directly in the forum, links to 3rd party sites may get blocked by (company) firewalls!

Again: Does the LabVIEW/DAQmx version you use even support your hardware? You just mentioned LabVIEW8.0, which is rather old…

Edit:

I just read the "Getting started" manual for the 7831R, it mentions LabVIEW FPGA and the RIO drivers.

I guess you already read this document too: you're sure you have the needed drivers installed?

[Duplessis]

Hi GerdW

>"NI 781xR and 783xR devices require the LabVIEW FPGA Module 7.1 or later and NI-RIO 1.3 or later driver software."

So it should be compatible.

(Yeah the material i'm using is pretty old.)

I guess i have the RIO driver installed, doesn't appear in the driver control menue but have  "NI-RIO" folder (it is Ni RIO 2.0)

Same thing go for Labview FPGA driver, i have got a folder named " LabVIEW FPGA Utilities"

[natasftw · Accepted solution]

The DAQ Assistant SHOULDN'T pick up your FPGA.  You're looking at different sets of drivers.

I'd expect to see the device in your PXI system in MAX, though. 

To work with this device, you don't add the DAQmx code into your code and go from there.  You'll never get a reading.  Instead, you add a target to your project.  Do you have a controller in your PXI chassis or are you connecting it directly to your PC?  If you have a controller, is it WIndows based or RT?  If it's Windows, you'll want to work from the PXI itself.  If it's RT, you should be able to see everything from a remote connection.  If there isn't a controller, try shutting off your PC and PXI.  Power the PXI first and then the PC.  You'll only read what's in the PXI chassis when your computer boots.  If you added anything to it, you won't see this.

I can't remember off the top of my head.  But, I believe you'll right-click "My Computer" in your project to see the R-Series card.  Choose "New Targets" and find your card.  If it's not listed there, right-click the project name instead.

For this device, ignore the DAQmx palette entirely.  It's useless to you.

[Duplessis]

>I can't remember off the top of my head.  But, I believe you'll right-click "My Computer" in your project to see the R-Series card.  Choose "New Targets" and find your card.  If it's not listed there, right-click the project name instead.

Thanks a lot, i've been able to find the PXI 7831-R card, it now also appeared on MAX.

But now i'm a bit confused, I have no clue about how to create the PXI 7831-R entry on the VI without the DAQ assistant (which anyway doesn't seem to detect the right driver), furthermore the measure Entry/Exit folder is rather empty. (took a screenshot)

Should I program the FPGA card?

[GerdW]

Hi Duplessis,

you don't use any DAQmx function at all.

You need to use LV-RT (Realtime) functions or even go down to the LV-FGPA level…