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Freeze and Frequency Analysis

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Re: Freeze and Frequency Analysis

Hey Alex,

I still have just a straight line. Its like my MEMS gets no data, but i made a test in the DAQmx and the hardware works fine. I added some screenshots. You have any idea? Smiley Sad

The error message is also strange because i setted everywhere the same rate(1kHz) and samples(100) like ago. Or did i missed it somewhere?

Thank you very much!

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Message 21 of 42
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Re: Freeze and Frequency Analysis

Hello Gregory88,

disable the highlight mode

best regards
Alexander Glasner
CER AES
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Message 22 of 42
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Re: Freeze and Frequency Analysis

no change Smiley Sad just a straight line at -5 volts-5V.jpg!?!?!?

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Message 23 of 42
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Solution
Accepted by topic author Gregory88
12-09-2016 01:47 AM

Re: Freeze and Frequency Analysis

Alex... i think i know why.. is it because i have changed the DAQ card? last week i used the SCB 68a with a PCI card. Now its a USB 6001 from NI

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Message 24 of 42
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Re: Freeze and Frequency Analysis

Thank you very much for your help and your patience! It works FFT.jpgSome last questions:

For understanding: 1. why makes the FFT in the first milliseconds always this one big peak?

2. the amplitude in the FFT is in Herz?

For the program:

3. could it also be possible to vary the waveform graph 2 and 3 from 10 seconds manualy into 15 or 20 seconds? e.g. through a rotary knob?

 

 

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Message 25 of 42
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Re: Freeze and Frequency Analysis

Hello Gregory88,

 

1. This could be the dc part in your signal.

2. What are the Output Units of FFT-based VIs?

3. Attached

best regards
Alexander Glasner
CER AES
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Message 26 of 42
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Re: Freeze and Frequency Analysis

Hi Alex,

 

thank you it´s also a nice feature, it´s great thou, but i would like to scale the x-axis and maybe y-axis by a rotary knob.

 

Furthermore i tried to write the data from the "waveform 2" & "waveform fft2" into a excel chart to print and compare them. Attached my VI with Express tools Smiley Embarassed does´nt work as expected :/

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Message 27 of 42
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Re: Freeze and Frequency Analysis

Hello Gregory88,

 

How Do I Programmatically Format the X-Axis of a LabVIEW Graph to Display Timestamps?

With this way you can set also the minimum and the maximum for each axis.

 

There is also a method export grap to excel

Daten von NI LabVIEW nach Microsoft Excel übertragen

 

Save to a series of files and use the true to generate a new one.

Unbenannt.PNG

best regards
Alexander Glasner
CER AES
Message 28 of 42
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Re: Freeze and Frequency Analysis

Hi Alex,

the scale with the x and y axis doesnt work, just the description changes the graph stays constant. :/

 

An "extra" idea for my VI is to create sth like a RMS - all three voltage signals (x-y-z-axis from the analog sensor) could combine together and could be visual in an extra waveform. would be usefull that i dont have to switch between the 3 signals of the sensor and compare everyone after each measurement.

 

attached the VI

 

 

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Message 29 of 42
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Re: Freeze and Frequency Analysis

Hello Gregory88,

 

like this

Unbenannt.PNG

 

for the scaling the range maximum property can be used.

best regards
Alexander Glasner
CER AES
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Message 30 of 42
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