Script error: At least one FFT function must be selected!

[flupa]

Hello,

I have written a script to analyse my data. I have written 2 new code sections:

1. calculations to get a Bode Plot

2. calculations to get a Waterfall diagram

My problem: If I run these scrips one by one they work as requested. But if I run them serial, I get the following error: At least one FFT function must be selected!

Does anyone have a clue on this?

Regards

Patrick

Message Edited by flupa on 03-13-2008 03:32 AM

[flupa]

Hello again,

If my description was not helpfully I am sorry. I am using V 9.1. Did anyone had that fault once too?

Regards

Patrick

[flupa]

Hi,

If none knows that error message I should start to describe my problem:

I have a time,speed, keyphasor and a proximity sensor signal.

First Part: Bode

1. I do a FFT with time and proximity sensor (CHNFFT1) -> Amplitudes
2. I do a transfer calculation with time, keyphasor and proximity sensor (CHNFFT2) -> Phases
3. Aritm. mean of speed in intervals (STATBLOCKCALC) -> Reverence Speeds
4. Take the Amplitudes and Phases of every interval at the frequency of the first Order at the reverence speed

So far so good.

Second Part: Waterfall diagram

1. Order Analysis in frequency domain (CHNORDAFCALC)

And now the error occurs (at this command: CHNORDAFCALC): "At least one FFT function must be selected!"

If I comment the first part, the second part works. So I really have no Idea what else to do.

Regards
Patrick

[Twigeater]

Hello Patrick!

Do you set all global parameters before using CHNORDAFCALC? You get a list in the help.

Matthias

[flupa]

Yep, I think so. I recorded a macro an took the code into my script and replaced some values with variables. As I said: without the first analysis befor it works.

My settings:

  GENXBEGIN        =SpeedMin
  GENXEND          =SpeedMax
  FFTWNDFCT        ="Hanning"
  FFTWNDPARA       =10
  FFTWNDCHN        ="time"
  FFTWNDCORRECTTYP ="periodic"
  FFTCALC          =0
  FFTAMPLTYPE      ="Ampl.Peak"
  FFTAMPLEXT       ="No"
  FFTPHASE         =0
  ORDAFSIGWEIGHT   ="NoRef"
  ORDAFREVOLSTEP   = stepWidth          
  ORDAFTYPE        ="Frequency"
  ORDAFFFTLENGTH   = intervalLengthFFT 
  ORDAFMAXORDER    =10
  ORDAFFILTRECALC  =5

At least the last two should not be necessary if ORDAFTYPE ="Frequency".

Regards
Patrick

[Brad_Turpin]

Hi Patrick,

I think the easiest way for us to help would be for you to post a data set and your full script application that runs both portions of the code.  If you don't want to post it, you could alternatively send it my email address:  brad.turpin@ni.com

Brad Turpin
Product Support Engineer
National Instruments

[flupa]

Hi all,

Brad solved my problem and I wanted to tell anyone who might have the same problem in the future how to fix that:

I just had to add the parameter:

FFTAmpl          = 1  

Thank you again Brad!

Regards
Patrick