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Buffer for Load Cell Data Collection with NI myDAQ

Hello,

 

I am using a myDAQ to collect impact force measured with a FUTEK LCM325 FSH04009 load cell (http://www.futek.com/files/pdf/Product%20Drawings/lcm325.pdf). My issue is when doing the conversion from millivolt input to force measurement, the conversion requires multiplication by 2000 lb unit conversion which amplifies any noise in the load cell reading (a static reading with no force applied gives a reading of +/- approximately 15 lb). Is there a buffer or some labVIEW function suitable to use to smooth out my reading but still collect an adequate number of sample points to analyze the impact? (myDAQ sample rate according to the spec sheet is 200kHz, so I would be looking at 200 samples for a 1 millisecond impact)

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I do not see any problem here, if you multiply your data, your signal-to-noise ratio just stays the same...

What you could do, is to use some background noise removal method. One of the most simple is a rolling average. Another simple way is that, before data conversion, you define a "+-threshold" value: set it as it gives you the +- amplitude of the background noise. Now you just simply go through all of your data points, and zero those values which fall into this background threshold interval...

 

edit: of course you could also do some more sophisticated noise removal, like filters acting in the frequency domain. Could you upload a typical measurement data including the background noise and the impact signal both? People could have a look at your raw data, and probably recommend you how to filter out the noise...

Another thing is to "attack" the noise from the hardware level. Did you do your cabling properly? Do you use proper grounding and shielding? http://www.ni.com/white-paper/3344/en/

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