Whether NI 6259 (M Series) can do AC coupling?

[lyrock]

I am going to use it to collect acceleration signal and this AC coupling function is important for this application.

I searched the NI support, and found some materials about the AC coupling. It said that not all DAQ devices support AC coupling.

I read through the references of this card, tried to find AC coupling in the DAQmx setting, and didn't succeed.

Wondering it cannot do AC Coupling.

Is there anybody can give me a comfirmation or any suggestion. thanks!

[devchander]

Yes, this card does not support AC coupling

You could probably switch to DSA  cards as they are built for the kind of applications that you speak of

[AnalogKid2DigitalMan]

Any possibility of selecting a suitable capacitor to add in series with the input to the DAQ to block DC/low frequencies to achieve AC coupling?

[devchander]

Theorotically, it seems possible.

But Personally and Practically, I have never tried it

So cannot really comment on it

Message Edited by devchander on 10-24-2006 02:24 AM

[Abhinav T]

The following Knowledge Base article has details on the capacitor that adds AC coupling to a signal (it is essentially a high pass filter):

Basic Information about AC and DC Coupling

The capacitor has to be extermely small to ensure no low frequency AC signals are omitted.

In addition to the DSA cards, S-series boards also support AC coupling according to this KB.

Abhinav T.
Application Engineer
National Instruments