create a DSA in Labview

[Oli Oli Oxin Free]

Hi

I would like to create a vi that does some of the things a Digital Signal Analyzer(DSA). I have done bits of the program and would like some help on some of the parts. I am using the NI cDAQ-9172 and I have in it a NI 9205 that has a 32 channel analog input. I'm only using 4 channels from them and I have already configured the DAQ assitant with the device. I have a signal that's going through and what I want is to create a FFT graph from the signal and using my formula that I have, I'm taking the peaks of the fft and getting temperature from it. From there, the temperature would be the x axis and depth would be the y-axis. The audio signal is coming from a device in the water. What I'm having problems with is first, how do I configure the DAQ assitant to only plot the channel that I want and not plot it all on the graph because sometimes, I'm only using one channel. Initially the VI was done to use the information from the 4 channels on the 2 DSA using the virtual instrumentation and now what I'm trying to do is change the program to not use the DSA at all in the program and create my own VI. There is a autotrigger function in the DSA that I would like to implement which I don't know how?. Also, I have the portion of the code that determines the peak of the fft but I don't know if it works or not. I have attached all the VI's that I have done. The workinprogess.vi is the work I'm working on now and that is getting the info from the DAQ and applying a FFT on it and suppose to find the peaks but I can't tell cuz i don't know how to add cursors to the graph and the main program that doing the whole thing is the bathyprogram which is taking all the info from the DSA and graphing it and everything that the DSA is doing in that program, I need to change to my own code. I really appreciate you taking the time to read my questions. It is a little harder than most programs and I would really appreciate anyone helping me with this. This is a program that needs to be done in a couple of months. 

Thanks in advance

Mohammed Tayel

[Oli Oli Oxin Free]

Those are all the VI files used for the program.

Thanks again

[GerdW]

Hi Oli Oli Oli,

just a side note: did you know you can create libraries from vis (*.llb)? Or put all vis into a ZIP archive to attach only one file...

[Oli Oli Oxin Free]

Could anyone help me or have any inputs?

[Ipshita_C]

Hi Oli Oli Oli,

I read your post and understand your concerns. However, it would really be great if we could narrow down the VI and work explicitly on the sections you are having problems with. Can you please put up a second post perhaps discussing what section of the code you want to start with and we can go from there. The FFT looks fine although in terms of data, I would verify it once.

Ipshita C.

[Oli Oli Oxin Free]

Hi

Thanks for replying. There are a lot of things that I have finished and only a couple problems that I'm still having trouble with. I'm having problems implementing the auto trigger function. It is suppose to start when the object in the water reaches a certain depth. How do I implement that? Also, the "Do Reading" vi was already made by someone else that I can't get a hold off anymore. I'm not that experienced with labview but how would I be able to edit the vi so it could take the data from the daq assitant vi as an input.

Thanks again

Moe

[Ipshita_C]

Hi Moe,

I would like to have a few more details on exactly what aspect of the implementation you are having difficulty with and what do you want to send as an input to the DAQ Assistant. Thanks!

Ipshita C.

[Oli Oli Oxin Free]

Hey Ipahita

sorry for the wait. I got the whole program done but there are a few problems. It is not graphing because when I turned on the highlight execution it shows that all the data that is coming out of the autostart subvi is 0 so there are nothing to print. It would be greatly appreciated if you could try to figure it out cuz I can't find the problem. 

Thanks a lot in advance

Moe

[Ipshita_C]

Hi Moe,

You can wire output from a DAQ Assistant directly to a waveform chart or alternatively, you can convert the dynamic data to static data and wire it to a waveform graph. I would try that instead of wiring it to a Build XY Graph Express VI. Also I am unable to open your VI without errors. I would suggest putting your Work in Progress VI and all the sub-VIs that you have used in a single folder, zip it up and post it on the forum. I will then have all the VIs in one place. Thanks!

Ipshita C.