IIR filter for multiple ATD data

[naroowal]

I have 3 ATDs simultaneously sampling. The digital IIR filter works on the first board data of 16 waveforms. The second and the third ATD data do not get filtered at all. They just output zero for all the channels. I tried different instances of the IIR filter to be used with different ATD data and the result is the same. If I turn off the digital filter, then the data shows up correctly.

Please help.

Thanks,

Narayana

[Nadim R]

Hi Narayana,

I am not too familiar with what you mean by "ATD" - do you mean an analog to digital converter?.  Can you clarify your setup.  Particularly, what kind of signals are coming out of the ATD.  Furthermore, are all of the signals of the ATDs similar?  What type of specs did you specify on the IIR filter?

Regards,

Nadim
Applications Engineering
National Instruments

[naroowal]

Hello Nadim,

Thank you for replying. In fact I just came from the lab after solving the problem. Yes, it is an analog-to-digital board - with 16 inputs. All these boards are tied together with respect to sampling-using a synchronization cable. the ATD board is what NI used to call PCI-MI0-16E-4. During my troubleshooting, I realized that the data coming from the first board has a t0 and dt value in the waveform attributes. The other two boards did not have these two attributes - they were zero. Once I gave the waveforms the proper dt and t0 value, the IIR filter could operate on the waveforms. So the problem was solved.

But thank you for replying. If I did not make myself clear above, I can post an image of the code.

Thank you,

naroowal