There is a very good example program that ships with LabVIEW called FIR Windowed Filter Design that demonstrates all the functionality of the FIR Windowed Filter.vi. To eliminate noise on a DC signal, choosing the lowpass filter option is probably best. The FIR Windowed Filter can do this, but any lowpass filter (Butterworth, etc) should work as well. Experiment with the sampling rate and the cutoff frequency to achieve your desired signal to noise ratio.
There is a good article in the National Instruments Knowledge Base which discusses removing 50 to 60 Hz noise from a DC signal. Here is a link to that article:
How Do I Eliminate Powerline Noise from DC Measur
ements Without Using a Hardware Low-pass Filter?
The article says that averaging is an alternative to software filtering for eliminating noise on a DC signal. Hopefully, by experimenting with these two methods, you can achieve the signal to noise ratio that you are looking for.
John M
National Instruments
