Bandstop filter for displayed data from USB 6211 DAQ with LabWindows

[Ward]

Hello,

I've developed an application to measure and display data acquired from a USB 6211 NI DAQ. Because the measurements are sometimes contaminated with powerline hum, I'd like to be able to filter the data before plotting it. I'm acquiring several channels (up to 16), at approx. 1 kHz per channel, using a buffer of 1 second. The channels are grouped by scan number, and I plot them using plotstripchart. Before the plotting, I'd like to filter the (displayed, not raw) data array. How can I do this?

Greetings,
Ward

[Ward]

Hi,

I got the basic filtering to work using the GroupByScanNumber function and Bw_BSF filtering. One problem remains though: in the displayed data, a settle-in effect remains in the first 1/10th of a second (for each channel). I assume this is an inherant effect of the filtering, and only using a buffer with part of the previous acuired second and filtering the larger dataset would prevent this, correct? Or is there a faster way?

Cheers!

[RikPrins]

Hello Ward,

Sorry for the late reply. As far as I can see this is a good solution. The effect you seeing is indeed an inherant settle-in effect of a filter.

Regards,

RikP - National Instruments Applications Engineering