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Self-Coded Lowpass Filter

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Hi,

 

I'm fairly new to LabVIEW, and struggling with implementing a self-coded lowpass filter in my code. It works fine for simulated sine waves (as can be seen below). However, when attempting to lowpass load cell data acquired from a DAQ assistant, something strange happens. The baseline of the filtered signal is offset from the unfiltered signal, and the offset increases with decreasing cut-off frequency. I've attached the VI for the lowpass filter. Any help or insight would be greatly appreciated!

 

lowpass.PNGlowpassSimulate.PNGlowpassResponse.PNG

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Solution
Accepted by mikarn91

Hello mikarn91,

 

Welcome to the Forums! I made a test-vi to wrap around your VI, to make it easier to test it. I attached it in LabVIEW version 2016, you should be able to open it. (You probably have a similar file, feel free to attach it as well, makes the hurdle to start looking into your issue lower for others Smiley Wink)

 

I think I found your mistake: Removing the Negate in your Filter it workes much better for me.

LabVIEW_2018-04-13_11-15-41.png

LabVIEW_2018-04-13_11-18-04.png


Ingo – LabVIEW 2013, 2014, 2015, 2016, 2017, 2018, NXG 2.0, 2.1, 3.0
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Wow, talk about being blind to my own code. This fixed everything. Thanks!

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True Smiley Happy

Thank you for the feedback; I am happy we could help that fast!


Ingo – LabVIEW 2013, 2014, 2015, 2016, 2017, 2018, NXG 2.0, 2.1, 3.0
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