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Real-time audio pitch shifting in Labview?

December 14, 2017, 5:10 pm
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Hi everyone,

 

I'm relatively new to using Labview so am after some help. I am wanting to be able to use Labview to pitch shift inputted audio (from a microphone or from a file) by a specific amount. For example either up or down one musical octave (this would mean doubling or halving the frequency respectively) and then having it output to a speaker in real time (or at least with as little delay as possible). I've worked out how to bring the audio into Labview but am now unsure what would be the best way to do it (or if it even would be possible inside Labview). I have also done a FFT to produce a frequency spectrum of the audio but not sure if this is actually useful.

 

If anyone has any suggestions for the best course of action to take that would be great.

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labview

December 14, 2017, 7:48 pm
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can i read desktop notifications from labview?

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Calling different LabVIEW application from a shell application

December 14, 2017, 10:13 pm
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Hi all, 

We have different applications to test different products like Product A, Product B, Product C.

 

I need to create a shell application for the user to select the type of product they want to test.

 

I would like to know the methods of finding the location of all the three applications and calling them from the shell application.

 

Thanks in advance

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String to numeric array

December 14, 2017, 11:16 pm
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Hello everyone,

I have try to convert element by element from a 4-digits string to a 4-elements array. 

First, I convert the string to number by using decimal string to number function. But I can not find a way or a tool for converting number to array. Could you help me about that problem?

Thank you.

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FPGA Image Convolution Size error

December 14, 2017, 11:19 pm
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Hi all,

 

I am trying to use image convolution inside FPGA. The convolution is applied properly until 2600 pixels in x resolution. After that, the values seem to miss previous row data. 

 

In Detail: As convolution is matrix operation, image data needs to be stored for the operation. But it seems there is an inadvertent error storing only 2600 pixels per row inside FPGA. And hence the filtered output is calculated assuming these pixels to be 0. 

 

I have tried with different image sizes, different convolution kernels, and also in different targets (cRIO 9030 and IC 3173).

 

I have attached screenshot FPGA VI and an example image.

 

The example image shows an input image of 4000x2500 of same pixel value 16.The kernel is 3x3 of values 1 with divider=1. The RT image is processed using IMAQ convolute inside RT controller and has value 144 [(9*16)/1] for all pixels. But the FPGA processed image (zoomed in) has 144 until 2597 pixels and then 112 (7*16- showing 1 column of 2 rows missing) at 2598, 80 (5*16- showing 2 columns of 2 rows missing) at 2599 and 48 after that (missing 3 columns of 2 rows- current row is always present). 

 

Does anyone have a workaround for this or am I making some mistakes?

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LINX function

December 15, 2017, 1:45 am
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Hi everybody,

How is the "ultrasonic HC-SR04" function of the LINX functions installed?

 

Thank you.

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Rookie errors

December 15, 2017, 2:14 am
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Hi, im struggling here to try and get my VI to stop. I have a project due and im trying to take it step by step but i have come to a halt! can anyone suggest why this wont stop when i press the stop on the while loop around the program?

perhaps there is a smarted way to achieve what i am trying to do. basically tank 1 is to empty to 30% and then be filled by tank 2 to 90% capacity. 

 

any help would be greatly appreciated, new to all this.

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What boards other than cRIO can run LabVIEW RealTime?

December 15, 2017, 4:04 am
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I have a project where I want to program in LabVIEW, I would like my code to be run in Real Time, I would like the board to be a Linux-based operating system, and I would like the board to support serial and Ethernet communication. Unfortunately, due to external constraints, I am not allowed to use any NI hardware, so I cannot simply use a cRIO.

 

Are there any outside hardware vendors that support my requirements (LabVIEW, Real Time, Linux OS, Serial, and Ethernet add-on/ports)?

 

Thanks.

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TIFF Saving in Labview using open-source libraries

December 15, 2017, 4:53 am
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Hi, 

My requirement is to read and write a stack of images into TIFF format (multiple pages, directories , with customised metadata). I would like to do this using open-source libraries (C, C++ or preferably .NET) and build a code in LabVIEW.

I had explored an old post on the same using LibTiff dlls in LabVIEW (https://forums.ni.com/t5/LabVIEW/Labview-libtiff-implementation/td-p/929843) and tried utilising the same. However, all dlls and llbs / VIs attached in the post don't seem to work,  in that , I get an error message ' Library not found or failed to load' (attached image) for all Call library function nodes despite configuring it to point to the correct dll location in my local system. I have ensured that the right version of the dll is utilised as mentioned in the post. 

I am working on 32-bit LV (version 14.0.1, LabVIEW2014 Service Pack) on Windows 10 , 64-bit OS. The downloaded dll from the webpage said it was compatiblie with both 32- and 64-bit systems.

In this respect I would like some help in figuring out why this issue occurs. Alternatively I would also welcome your suggestions on various other TIFF utility libraries which can be used for my specifications (mentioned above) in LabVIEW.

Thanks in advance !

 

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include data type for array control refnum

December 15, 2017, 4:54 am
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Hi,

 

I have placed a control refnum from the front panel and linked it to the array. After linking i was unable to select the include data type option on the refnum in order to make it as a strict type def. Why unable to include the data type option.

 

I have attached the sample VI in which array control reference is included with its data type which i have converted from main VI to sub VI. But why it is not possible to convert a control reference to array reference with inclusion of data type.

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NI-FGEN SFP localization

December 15, 2017, 4:56 am
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Hello,

 

I would like to localize (translate strings in program and documentation) NI-FGEN SFP. I have found sfpArb_DynamicStrings_ENG.ini and translated it. Now I'm seeking sfpArb_VIStrings_Eng.ini file to translate. Where could I find it and how could I programmatically change SFP language to Japanese or add new language in order to read strings from new configuration files?

 

Thanks in advance

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How to set the scale of graph to display more numbers?

December 15, 2017, 5:45 am
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Hi,

How to setup the scale of graph to show like below?For example show 50 between 20 and 100...

Thanks,

 

what I wantwhat I wantwhat I havewhat I have

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PID or PWM for Servo?

December 15, 2017, 6:08 am
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I have a Moog Servo.  Attached is a synchro for feedback voltage to my circuit that is proportional ( PID?) to a wing position attached to the servo.  The servo is fully on when commanded (threw a DAQ 6229 Analog out) to an angle/position or off  once its at the commanded position ( PWM?) .  Everything I've read indicates this ..to me..is a hybrid PID/PWM controller.   ON_OFF_ON..etc.. would be the PWM and a PID to determine when it got to the commanded position.  The problem w the PID is it looks like it keeps looking at the process variable ( my synchro ) compares it to my setpoint ( my commanded angle) and tries to set the output to a voltage to get the wing position to its commanded position.  In my case I want to give the servo say 10 vdc and by measuring the synchro voltage take away servo voltage when the two are equal..

This is a "general" example but this is graphically what I envision..

The 2nd plot is what I think the PID does..it outputs a voltage or whatever constantly after you have adj the P, I and D.

 

Thanks..

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User Event, Producer- and Consumer Loop

December 15, 2017, 6:32 am
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I have an application in which I have a Producer Loop, which gives me data and apends this to a queue. The queue elements are then read in a separate consumer loop, since the analysis of the data is rather long. The producer Loop only enqueues every 0.05 seconds or so (as this is the time it takes to make a measurement).

The problem I have is that I have user controls which are required for the analysis, e.g. an Offset value. The user can change this value and the upated value is then applied in the analysis.

What is the best architecture for this?

I was thinking that instead of the present 2 loops, I add a third loop which handles User Events.

But then how do I get the new values into the consumer loop? Another queue? Wouldn't this affect timing? Another alternative would be to put all the controls in the already existing Producer Loop a,d bundle everything into a cluster (controls and data) and add that to the queue. This seems messy though.

Any experiences?

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Control position locked on front panel

December 15, 2017, 6:40 am
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Silly question, but it has me baffled. In LabVIEW 2015 the "Continuous Measurement and Logging" template example creates a front panel with a set of controls across the bottom. These controls move as a group as the main panel is resized. How is this done? I can select individual controls and move them, but can't select the group, as a group. I also notice that if I "show label" it shows "briefly" as a dotted outline "behind" some area above the control. If I move the control upward, the label is visible, and an area around the upper part of the FP is shown with a dotted line, briefly. I know that the front panel is probably created with scripting, but assume that it can be done manually as well.

 

Also, the scroll bars are turned off, and in fact can't be turned on in the VI properties "Window Appearance" window, they are grayed out.

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loop for a changing value

December 15, 2017, 7:10 am
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Hello,

 

I would like to create a loop function with a changing value. I want to create a binary image with the IMAQ threshold. Now I want to change the lower value in the front panel and I want that the new binary image appears on the screen.

 

So far I tried it with a case structure but I do not know how to compare the old value of the lower value with the new value from the front panel.

 

Can someone help me with this?

 

Thanks a lot!

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IMAQ template question

December 15, 2017, 8:58 am
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Hello,

 

I'm new to IMAQ so I'm not sure how to accomplish the following.  I wish to conduct a comparison between two images to evaluate defects.  The part in question, however, has a hole in the center and the background is NOT consistent (parts mounted in a GelPak at time of imaging so the background seen through this hole is highly variable).  How can I exclude a region within the ROI? (part outer dimensions are square)

 

As a side question: I can't find the IMAQ pallette functions (functions are currently accessible via quick drop menu only).  Where would I expect to find the Menu file?  (LabVIEW 2016)

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System Exec.vi wait until completion

December 15, 2017, 9:52 am
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I have a vi that uses the System Exec.vi to run a command line program from Atmel (atprogram.exe). Our current code has "wait until completion?" set to True and uses the standard output from the command line to see the output of atprogram.exe to confirm that the command completed OK and to get data back from atpgrogram.exe.

 

This vi has worked fine on four computers for a while. I tried yesterday to run the same program on a new computer and I keep getting an error. It appears the System Exec.vi is returning an error with a traceback that ends up with "WindowsError: [Error 6] The handle is invalid". This appears to maybe be something with a GUI, although atprogram doesn't use a GUI; anyway, that may be specific to atprogram, the point is it gets some type of error.

 

When I set "wait until completion?" to false the System Exec.vi runs the command fine and atprogram.exe does its job. The problem is then I don't get the standard output that I use in the rest of my vi to process data that comes back.

 

I have verified that running the string that is passed into System Exec.vi works fine just pasting it into a windows command prompt. And as I mentioned the command runs fine if the vi doesn't wait for completion.

 

Does anyone have ideas what to look for? It does seem like something specific to the computer that is causing the problem. But the wait until completion seems to affect it too.

 

 

 

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Image processing

December 15, 2017, 10:08 am
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Hi guys, 

I  come from Viet Nam. I am a student and I am studying Image Processing with Labview by myself. But I have a problem that I do not know how to trigger an area of a picture. Please give me your suggestion. Thank guys so much, my picture is below and I need to trigger license plate of motorbikes.

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PWM signal

December 15, 2017, 10:48 am
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hallo,

please how to generate a PWM signal with labview on a Arduino Board ?? ( i have already installed LINX or LIFA).

 

thx

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