Arrays, sub VIs

[Mbdeck]

I've attached my code for the VI that will read from the "write to text file VI" above. Is the "decimal to number" function in my VI the right function to use?.  I'm asking this because I built my own simulated temperature acquisition VI because I couldn't find a demo. The data from my simulated device is all over the place but I continued using it so as to learn the stuff even if the numbers weren't correct.  Anyways, I'd like your input on the coding above.

Thanks

[Mbdeck]

sorry here is the attachment

[Dennis_Knutson]

The Decimal String to Number is okay as long as all you want to read is integers. Otherwise use Fract/Exp String to Number.

[Mbdeck]

On another note, I'm trying to set up a cheap test station for Solar cell testing and I'm wondering if a Labview based oscilloscope and a USB-6009 DAQ accessory would suffice in this instance. Has anyone done this before?. I'd welcome any suggestions.

[Ipshita_C]

Hi Mbdeck,

Your solar cell would have the usual signal wires--positive and negative. You would need a couple of analog input channels and perhaps a ground. The USB 6009 should suffice. However, remember that it is not meant for sophisticated signals, so if you need to do any amplification or filtering you will need to build your own or use NI's signal conditiong SCB systems. Hope this helps.

Ipshita C.

[Mbdeck]

Thanks for your input Ipshita.  I just realized I needed to learn a little more about the USB-6009 that I have and I don't have all the accessories to use it at the moment. I've decided to use a simulated device to learn more on data acquisition, however, I'm not so sure if the device I created is working properly. Can some body take a look and see if it's correct? I was supposed to obtain a sine wave on the waveform graph but it seems to be a very low frequency wave that appears to be a sine wave.I'm not confident that this is really what I'm supposed to get.  Please see the attached  VI below:

[Ipshita_C]

Hi Mbdeck,

Simulated devices in MAX are not meant to generate signals--they are just used for setting up and looking at configurations. you should use the Simulate Signal express VI--it can generate four kinds of waves with noise. Please look at the attachment. Hope this helps.

Ipshita C.

[Mbdeck]

 Hello everyone,

Can someone help me out here. I just created VI that was supposed to filter a signal and take a fast fourier transform and then select the dominant frequency but the VI doesn't work when I try to run it. I think the problem lies in the filter configuration but I don't know how to correct it. I set it to high-pass but the config. dialogue box only allows you to set the high -frequency limit and not the lower limit. The low limit seems to be set a default value. Why is that?.  I will really apprecaite any input here. Please see the attached VI and thanks in advance.

[johnsold]

Your VI seems to indicate some confusion on your part about how these signal processing VIs work.

1. The filter is set to be a high pass filter.  Therefore it has only one frequency limit.  The other limit is grayed out because that is only needed for bandpass or bandstop filters.

2. The Tone Measurements VI uses FFT (spectral analysis) internally to find the tone.  Applying it to the output of the Spectral Measurements VI is meaningless.  You could use the peak detector VI at the output of the Spectral Measurements VI or apply the Tone Measurements VI directly to the Filtered Signal.

3.  The output of the  > comparison is a boolean value (carefully disguised in a Dynamic Data wire).  What do you want the Detected Peak indicator to show, the frequency of the peak?  If so, connect the Detected Peak indicator to the Tone Measurements: Frequency output.

Lynn 

[Mbdeck]

Hello everyone,

I'm having trouble acquiring a sound signal with an electret microphrone through a usb-6009 DAQ hardware. Has anyone done any sound signal acquisition with this microphone? I'd welcome any assistance on how to set this test up. Thanks in advance.