(Still) low pass filtering

[GerdW · Accepted solution]

Hi Milon,

Would you please mention the missing 'InitArray functions'? 

That's not what I wrote.

I wrote:

one of those InitArray functions was missing its size input…

Do you spot the difference in the sentences?

You need to wire all inputs of those two InitArray functions. I guess you are able to find them in your VI on your own…

[Chowdhury_Milon]

Respected Mr. GerdW,

Greetings. Although this problem is solved, I have attached a filtered signal graph here (for the mentioned LabVIEW code). I recorded 14 seconds of data. Before and after every second, a fluctuation has observed. I think it occurs due to skid (not continuous) sampling of DAQ. Curious mind wants to know, can we omit/reduce this fluctuation?

[Chowdhury_Milon]

Hello,

Recently, I am working in signal processing in Labview 2017. I got different filters (Butterworth to Advanced FIR) in LabVIEW. But, I was searching for a Kalman filter. When I searched in Find examples, the CDEx Kalman Filter.vi and related Kalman filter.vis are disabled to open. I have attached that picture. I also searched about it in the discussion forum but most of the problems are unsolved. My question is:
1. Why the Kalman filter is disabled?
2. is there any specific 'vi' for Kalman filter (like Savitzky-Golay)?

Another relevant question, I observed a fluctuation before and after every second of recording during using the 'Savitzky-Golay.vi'.  I recorded 14 seconds of data and have attached the graphical picture here. I want to know, can I omit/reduce this fluctuation? 

Apologize for my poor English writing.

[GerdW]

Hi Milon,

1. Why the Kalman filter is disabled?

Did you read the cause in the upper right corner? Pretty good explanation…

I recorded 14 seconds of data and have attached the graphical picture here. I want to know, can I omit/reduce this fluctuation?

When you still use the same approach as before (you didn't attach any actual VI) then you are reading data for 1s and apply your filter on that interval of data. The next iteration you read the next block of data and apply the filter again. But your filter "starts" again with each data block, it doesn't "remember" its last state: so there might/will be some filter artefact at the start/end of each data block…

You need to apply your filter "continuously". Did you see the "init/cont" input at those filter functions (in the SignalProcessing palette)?

[Chowdhury_Milon]

Respected Mr. GerdW,

Thanks for instant reply. I read the note for "Kalman filter' but didn't find any specific toolkit for that. In my computer, NI-DAQmx drives, NI-VISA toolkit  are already installed. I would be grateful, if you mention any specific link for Kalman toolkit.

[GerdW]

Hi Milon,

do you even bother to read the messages shown to you?

Do you see this "Requirements" field in the lower right of your image?

[Chowdhury_Milon]

Respected Mr. GerdW,

Thanks for your explanation of my previous questions. I read all the dictates for the Kalman filter. In the right upper side, they mentioned a toolkit need to install. I searched "Kalman toolkit" but didn't find. Lower right side mentioned a link. I didn't found any toolkit or relevant options there (maybe my misunderstanding/ignorance). I never bother to read the instruction as I need to solve my problems. Now, it seems, you feel bored to answer. If so, I am SORRY for that.

[GerdW]

Hi Milon,

In the right upper side, they mentioned a toolkit need to install. I searched "Kalman toolkit" but didn't find.

That message only mentioned a missing toolkit. It didn't say you need some "Kalman toolkit"…

Lower right side mentioned a link. I didn't found any toolkit or relevant options there

You found the Control, Design and Simulation (CDS) module - as is mentioned in the example finder.

Guess why that example has a name starting with "CD…"

So when you really want to see that Kalman filter example you need to install the CDS module - as is clearly written in the "Requirements" box!

[Chowdhury_Milon]

Respected Mr. GerdW,

I am still trying to solve the signal fluctuation. Although you explained that problem a nicely ( about "init/cont"), and I followed some examples, but couldn't solve that yet. I have attached the modified code here. Would you please check and give the suggestion for further steps...

[GerdW]

Hi Milon,

no problem on my side - after correctly wiring all those array functions (again!):