convert volts to frequency ?

[reteb1]

I run LV 8.6 and a MIO Daq 16-E-1.

The DAQ I/O Assistant works flawlessly.

I have been trying intensively - in vain - to see a frequency spectrum analyzed graph of the DAQ ( which outputs voltage only when using the DAQ I/O Assistant with this DAQ card ).

Every attempt I made results in a time X axis instead of the wanted frequency X axis.

I tried the Express vi " Spectral Measuments " , various FFT vi's , the add-on " Spectral Measuments "  and the Signal Processing " Signal Analysis ".

All of them were outputted to a Waveform Graph, partly thru a power spectrum cluster wire , partly thru a double complex wire and partly thru a dynamic data wire.

All of my attemps did produce a Waveform Graph, but only with a time X axis, no freq X axis.

Very obviously, I do oversee something very basic.

Any help would be appreciated.

[Dennis_Knutson · Accepted solution]

The x axis 'Time' is just a text label that you can change to whatever you want.

If the data is not correct, that is a different story. I don't understand what you mean by 'partly'. There should be a single wire from the Express VI to the graph.

[reteb1]

Thanks !

Part of the problem resolved.

I was unaware that changing the X axis label would also change the time units into frequency units

( I presumed the X axis labels were just text labels without  effect  ).

Two of my trials do work properly now ( i.e. DAQAssistant>Express>Signal Analysis>Spectral Measurements>Waveform Graph as well as  DAQAssistant>Sound and Vibration>Frequency Analysis>Baseband FFT>Power>SVFA Power Spectrum.vi>Waveform Graph ).

Two other trials ( FFT transform vi's ) ) do not work properly or not at all.

I try to find out what's up but I am somewhat puzzled by the many FFT.vi's

With " partly " I meant my various trial configurations showed various output lines into the Waveform Graph ( e.g. the Spectral Measurements.vi outputted a blue dynamic data line and the SVFA Power Spectrum.vi outputted a cluster of 3 elements pink line. ).

For this moment I can go on.

[reteb1]

---

>reteb1 wrote:

>I was unaware that changing the X axis label would also change the time units into frequency units

>( I presumed the X axis labels were just text labels without  effect  ).

Oops, having been too premature, I have to correct myself.

Changing the X-axis label from time to frequency is just a text label indeed ( without any effect ).

Just as Dennis Knutson said.

In my two working configurations as explained above the X-axis produces frequency units anyway, whatever the X-axis label is named.

Problem was my wrong ratio " samples to read " versus " rate " in the DAQAssistant.