Swept Sine using Sound and Vibration Toolkit 3.1

[w_lodiman]

Dear All...

I'm trying to develop swept sine measurement using PCI-4451 card, LabVIEW FDS, and Sound&Vibration Toolkit 3.1.

I get problem while running vi that I've made.. I can't set the parameters for generating the swept sine signal. I can only run it in its default value (frequency start = 100, frequency stop = 10000, and number of step 100). When I change the either one of them (frequency start/frequency stop/number of step), my card odesn't generate any signals at all..

Can anyone help me?

Here's enclosed picture of the vi that I've made..

Thank you..

[Hani R]

Hi,

From what I understand, you do not get any output for values besides the default values that you set for frequency start, frequency stop or the number of steps.  What are some of the values that you have tried so far? 


Can you also attach the VI you are using so I can take a look at your other settings?

[w_lodiman]

Hello Hani R..

I've tried a lot of combination, such as: (frequency start = fstart, frequency stop = fstop, number of step = n)
1. fstart = 100, fstop = 1000, n = 1000
2. fstart = 10, fstop = 100, n = 100
3. fstart = 20, fstop = 100, n = 50
4. fstart = 1, fstop = 10, n = 10
5. many more..

I tried lots of combination but it doesn't work.. Do you ever had the same experience?


about the vi.. as far as I know, isn't it the toolkit is a patent of National Instruments so that it can't be distributed freely? because, I've browsed some thread and usually people don't attach their vi.. only the screenshot of it.. CMIIW..

Thank you..

[Hani R]

Hi w_lodiman,

I tried your VI on a PCI 4451 and found that changing the default values to certain other values causes an error in the SVFA Power Spectrum VI.  However, I do see a frequency sweep being generated when I disabled the SVFA Power Spectrum VI. 

When you say that you are not obtaining any output when you change the default settings, are you getting an error with the SVFA Power Spectrum or are you speaking of something else? 

[w_lodiman]

Hello Hani R,

I don't understand what you mean with "SVFA Power Spectrum".. Do you mean the SVT Power Spectrum.vi?
I've already tried to delete the SVT  Power Spectrum.vi, but I'm still having the same problem..

My problem is I can't obtain any output when I'm changing the parameter for generating swept sine signal.. I simply only get noise in my input or Error 1901 occured..

FYI:
Error -1901 occurred at SVT Swept Sine Engine (Traditional DAQ).vi
Possible reason(s):
Sound and Vibration Toolset:  The maximum test frequency is above the alias-free bandwidth for the specified sample rate. Increase the sample rate or decrease the maximum test frequency.

Can you help me?

[dsb@NI]

w_lodiman,

In SVT 3.1 up to SVT 5.0 (Hani R, it appears that you are using the most recent version) you can use SVT Set Swept Sine Sampling Frequency.vi to explicitly set the update/sample rate that will be used for the measurement.

As a first step, please refer to one of the swept sine examples (SVXMPL_Getting Started with Swept Sine (Traditional DAQ).vi and SVXMPL_Swept Sine FRF (Traditional DAQ).vi).

Right now I can verify that the Getting Started with Swept Sine (Traditional DAQ) example works with non-default sweep frequencies on an MIO device with Traditional DAQ 7.4.4. I will try the example on a 4451 tomorrow.

What version of Traditional DAQ do you have installed?

[w_lodiman]

Dear Doug,

---

dsb@NI wrote:

As a first step, please refer to one of the swept sine examples (SVXMPL_Getting Started with Swept Sine (Traditional DAQ).vi and SVXMPL_Swept Sine FRF (Traditional DAQ).vi).

---

Ok I'll try the example tomorrow..

Well, I'm using NI-DAQ 7.2 for the driver..


Regards,
William

note: sorry, all.. since the first post I've always forgotten to write my name.. thanx..

[w_lodiman]

Dear Doug..

I've already tried the "SVXMPL_Swept Sine FRF.vi".. When I was running the vi, I got this error message:
Error -10803 occurred at SVT Swept Sine Engine (Traditional DAQ).vi
Possible reason(s):
NI-DAQ LV:  The on-going transfer has been stopped.   This is to prevent regeneration for output operations, or to reallocate resources for input operations.
Can you explain for me about this error? FYI, I didn;t change any configuration of the vi when running the vi..


I've already tried the "SVXMPL_Getting Started with Swept SIne (Traditional DAQ).vi".. It works well.. I can generate the swept sine signal and I can adjust the frequency stop, frequency start, and number of step..! Great man!
Simple conclusion from my opinion, I don't give enough settings and configuration in my vi which make it run to error.. I'll learn this vi right away now..
Thanks alot Doug..


Best Regards,
William

[dsb@NI]

William, I am very sorry to have been out of contact for the past two days. I am glad to hear that the Getting Started with Swept Sine (Traditional DAQ) Example works for you. The -10803 error that the more advanced example gave you is essentially a performance error stating that the computer could not keep up with the acquisition while performing the display updates and servicing other programs that may be running. One simple way to free up more of the host processor for the generation/acquisition is to shut down any other programs that don't need to be running. Also, you can minimize the amount of display updates that need to happen by doing something as simple as leaving the tab on the example on the Getting Started Tab. Generally, I find that this is enough to allow my computer to make the swept sine measurement even with small block durations (duration < 50 ms). Another option is to increase the block duration to 150 or 200 ms. This will generally cause the sweep to take a little longer, but the longer block duration seems to better tolerate momentary interruptions/lapses that happen with Windows OS.

[w_lodiman]

Dear Doug..

Thank you for the explanation..
If you see DSA forum, I've also posted another question about "block duration" (link), which I'm still confused about..
Can you help me again in determining the "right value" for block duration?

Thank you..


Best Regards,
William