Multifunction daq

[C-Dav]

Imran,

It sounds like what you are experiencing currently is either 'ghosting' or 'crosstalk' in your measurements.  The following documents will do a better job of explaining it than I could:

Ghosting: http://digital.ni.com/public.nsf/allkb/73CB0FB296814E2286256FFD00028DDF

Crosstalk: http://digital.ni.com/public.nsf/allkb/B9BCDFD960C06B9186256A37007490CD

They should also provide some considerations you can make to alleviate this behavior (like using two channels that are physically further apart than ai0 and ai1, for instance).

As far as the other issue is concerned, I have spoken extensively with some of our DAQ experts and the only conclusion we can draw is that the incompatibility between the motherboard of this specific computer and the DAQ interface (the same incompatibility that requires interrupts to be used instead of DMA) is causing this strainge input behavior when the AI and AO are used at the same time.  I do apologize for this because I know it must be an inconvenience, but the best work around we can suggest is using your DAQ card with another computer where DMA works without any trouble.

Let me know if you have any further questions.

Regards,

[Emran]

As far as the other issue is concerned, I have spoken extensively with some of our DAQ experts and the only conclusion we can draw is that the incompatibility between the motherboard of this specific computer and the DAQ interface (the same incompatibility that requires interrupts to be used instead of DMA) is causing this strainge input behavior when the AI and AO are used at the same time.  I do apologize for this because I know it must be an inconvenience, but the best work around we can suggest is using your DAQ card with another computer where DMA works without any trouble.

Let me know if you have any further questions.

Thanks for articales sir!

 I'll read and inform you about the results regarding ghosting issue lator sir and i'm using allmost all the analog inputs of daq thats why it is impossibal to use physically far away analog input channels.

As far as the other issue is concerned sir that is solved because as you already said and now it is proved as well that by selecting data transfer mechanism to intrrupt it does not effects the health of any ai.The reason for turning into garbage like data was the ghostin/crosstalk ,i sent you the application describing behaviour of input when only two analog inputs were used but in my real application i am using almost all ai's thats why waveform(because of ghosting/crosstalk) was being disturbed severly.

One question may be arise sir why input was not being effected by ghosting when we were using  dma data transfer mechanism?

Sir answere is(as i understan) by using dma we were not able to generate more than 100hz(in this pc) and this frequency is too low to take part in ghosting and when we shifted to interrupts we generated high frequency  that can play a role in ghosting.

And sir in my thread where is the option "Accept as soloution"? only "Reply "option is present.

Thanks

Emran

[Emran]

As far as the other issue is concerned, I have spoken extensively with some of our DAQ experts and the only conclusion we can draw is that the incompatibility between the motherboard of this specific computer and the DAQ interface (the same incompatibility that requires interrupts to be used instead of DMA) is causing this strainge input behavior when the AI and AO are used at the same time.  I do apologize for this because I know it must be an inconvenience, but the best work around we can suggest is using your DAQ card with another computer where DMA works without any trouble.

Let me know if you have any further questions.

Thanks for articales sir!

 I'll read and inform you about the results regarding ghosting issue lator sir and i'm using allmost all the analog inputs of daq thats why it is impossibal to use physically far away analog input channels.

As far as the other issue is concerned sir that is solved because as you already said and now it is proved as well that by selecting data transfer mechanism to intrrupt it does not effects the health of any ai.The reason for turning into garbage like data was the ghostin/crosstalk ,i sent you the application describing behaviour of input when only two analog inputs were used but in my real application i am using almost all ai's thats why waveform(because of ghosting/crosstalk) was being disturbed severly.

One question may be arise sir why input was not being effected by ghosting when we were using  dma data transfer mechanism?

Sir answere is(as i understan) by using dma we were not able to generate more than 100hz(in this pc) and this frequency is too low to take part in ghosting and when we shifted to interrupts we generated high frequency  that can play a role in ghosting.

And sir in my thread where is the option "Accept as soloution"? only "Reply "option is present.

Thanks

Emran

[C-Dav]

Imran,

The 'mark as solution' can only be used once per forum thread, and I believe an earlier post in this thread was already mark as the solution.  You may be able to de-select that post and select another if you wish, but I've never actually tried that.

This could explain what has been going on, as ghosting would be augmented at higher frequencies.

Regards,

[Emran]

Hi

sir i m on vocations from ofice til sep,after returning back i,ll be able to perform testings related ghosting problem,than i,ll inform you about the results.

thanks