labview 5.1 and ni-daq 6.9.1 acquisition problem

[highkftj]

Hi all,

I have a DAQ acquisition system with the two software versions above specified. I am trying to acquire a sinusoidal wave of 240Hz and 5V amplitude.

These are the steps I have followed as advised in the manual.

1) Function generator outputs a sine wave of 240Hz and 5V pk-pk

2) I have wired the signal to the breakout board for a differential measurement on channel 0: + on ACH0 (pin68) and - on ACH9 (pin34)

3) As acquisition parameters I set sampling rate = 200*240 = 48000Hz and data points 200*4 = 800 in order to capture 4 whole periods with 200 data points each

4) I set Device 1 and Channel 0

From labview I can just see a constant line at 10v then using the test channel from ni-daq software I can see that the input to the acquisition card is a step value which jumps between 0v and 10v, but no sinusoidal behaviour at all.

The labview project VI works correctly with other acquisitions (temperature measurements) so I can say it's not the problem.

I don't really know what other parameter I could change. Anyone has an idea of what is the problem or how I can diagnose if the acquisition card/breakout board has any hardware issue?

Thanks in advance!

[Dennis_Knutson]

Is that a typo or do you actually have AI0 and AI9 connected? For differential, it should be AI8 instead of AI9.

[highkftj]

Hi,

yes sorry it was a typo.. pin 34 is ACH8 (negative for differential on channel 0).

Any clue why I get a straight line at 10v in my acquisition screen? From a DSO hooked up on the same signal I can clearly see the sine wave at 240Hz and 5v pk-pk.

[Coq_Rouge]

You can use MAX to test things without programming. But I will guess your configuration is wrong. Check out the Daq card user manual for recommend ways to connect to your system with different input configurations

[Coq_Rouge]

By the way, you can use newer versions of Labview together with ni-daq 6.9.3. I have used Labview 8.6 and version 6.9.3 without any problem

[highkftj]

HI,

WHERE I CAN FIND THIS MAX? ALSO I FOLLOWED THE CONNECTION PROPERLY WHICH IS PRETTY STRAIGHTFORWARD, ONLY TWO WIRES, SO I NEED TO TEST THE CARD

IS THERE ANY FREE UPGRADE OF LABVIEW?

[Coq_Rouge]

You can look for the file here .........program files\National Instruments\MAX\NIMax.exe

And yes Labview has been updated a lot since Labview 5.x 😉 But those updates are nor free

Message Edited by Coq Rouge on 04-15-2010 05:05 PM

[Dennis_Knutson]

MAX is Measurement & Automation Explorer and should be on your desktop assuming that the version of the DAQ driver is not so old that MAX was not used. I don't remember that far back.

No, there is no free upgrade of LabVIEW.

[highkftj]

Thanks for your help, this morning I got it worked but I still think the card has a problem. The connections are correct since when it works I can see the right sine wave.

As I said I believe there is some sort of hardware issue in my system: I went to Measurement & Automation Explorer, under device, I tested the device. I got an error saying that the primary interrupt has a problem. I went ahead and in the windows of the device test panel I could see the signal correctly. I started labview and took my measurements. After 5 min of acquisitions, in the windows of the test device of Measurement & Automation Explorer the signal went back to a straight line at 10v and of course I couldn't read anything anymore in labview project (only the straight line at 10v).

I closed all the programs, wait 5 minutes and restarted Measurement & Automation Explorer, tested the device again, aquired with labview and everything was fine... Till again a straight line after some time.

I guess there is a problem of suspension/hardware on my system. I will try MAX right now, but is it normal I have to costantly test my device to push a reading?? Indeed if I don't follow this procedure, labview cannot read anything.

Thanks!

[highkftj]

So I figure out through MAX, i.e. the explorer, that my card sometime read a constant value of 10v, while other times it correctly see the wave form.

When I start testing my device (PCI-6023) from MAX, I got this error:

"The device is not responding to the first IRQ level. Continue with the test panel?"

Saying yes to this message brought up the panel but again in a total random way the card sometime 'see' the waveform other times 'see' constant value of 10v...

Any idea about that?

Also I have another machine with the latest version of labview, but I don't think I can open my VI project or that this is compatible without recompiling. Do you have any suggestion about that either?

Thanks!