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What would cause build info to disappear from a project?

June 7, 2017, 3:06 pm
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I am working on a project that hasn't been looked at in a few months.  According to SVN, there haven't been any changes since I last committed, yet somehow all the build info is missing.

 

It's not a big deal because it is easily reproduced, but still yet... what could've happened?  I grabbed versions of the .lvproj file all the way back to the first committed version, but it didn't have the build info in it.  I was under the impression that the build info was saved in the .lvproj file, but it would appear that I am wrong?

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How to add 1D arrays and then divide to find an average array?

June 7, 2017, 3:25 pm
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Hello All,

 

I have a 1D array that is being generated inside of a case. This array leads out of the case, and I want to be able to add it to the previous array created, which is why I have it in a For Loop. As you can see in the picture attached, I am trying to figure out how to correctly add the current array to the previous one, and once the for loop is done, divide the added array by the number of iterations (basically the number of arrays added). Would this give me the averaged array? I want to average the array so I can find the averaged Max of the array which is being filled in by a frequency sweep.

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plot data acquired in a loop in real time

June 7, 2017, 4:07 pm
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Hello,

I am acquiring data, and doing some basic processing inside a loop. I would like to plot this data in a real-time way every time the loop executes i.e. data on y, loop iteration on x, and have the plot show data from previous loop iterations too  (not just the current one). I'm trying this using shift registers and arrays to clusters, but what shows up on my plot is a single point that updates every loop iteration. I can get what I want, superficially, by just putting the data on a waveform graph, but that updates with time and not loop count. I have also tried plotting the data array directly, but I haven't had success with that either.

 

I've attached my vi, and the relevant part to this question is at the bottom of the case structure.

 

Thank you!

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Defer panel updates when using activex webbrowser

June 7, 2017, 4:33 pm
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I am working on a LabVIEW application that performs a series of tests and generates an HTML report.  The report is displayed using the Microsoft web browser inside an activex control.  To do this, the report is saved to a file and then the file location is passed to the browser using the Navigate method (IWebbrowser 2).  The report and its view should be updated after each step of the test.  This is currently being done by generating the current edition of the report after each test step, saving it to the same file, and then calling the Refresh method of the browser.  This works fine unless the report does not fit in the browser window (scrollbar needed) and the scroll bar has been moved down from the top.  In this case, the Refresh method causes the scroll bar to move to the top, the latest report is displayed, and then the scroll bar returns to its previous position.  The final position of the scroll bar is what I want, but the redraw appears glitchy.  I tried to deal with this by deferring front panel (using a property of the front panel) updates while the Refresh node was called, but this did not keep the activeX control from updating.  Does anyone know how to prevent this glitchy effect, perhaps by suppressing the rendering of the activeX control until it has finished updating, or some other way?

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Digital to analog conversion labview

June 7, 2017, 5:03 pm
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Hello All,

I want to convert digital output from arduino to analog. for that i am using Adafruit MCP4725 (DAC). DAC should be connected to SDA and SCL pins of arduino which 20 and 21 in Arduino MEGA.

My queries:

1. In labview arduino Digital Write block only shows 0-13 pins to write but it shows for Uno Arduino. If i am using Arduino Mega then it will work automatically i am using digital write 20th pin.

 

2. Can i connect PWM output to SDA pin of DAC.

 

 

Thanks

Siddharth

 

 

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Editing a subVI's input lines

June 7, 2017, 6:15 pm
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I'm working with a piece of code created by the (unfortunately recently inactive) author of this example. In short, the code feeds a square wave to user-selected lines on a NI-DAQ. I'm trying to make adjustments to the array below, such that each of the cells/elements includes a control/menu for an offset. As is, the user can only specify frequency and duty cycle, but for my application, I want to be able to include an offset to the square wave. image.png

I can go into the array for this and customize it so that there's a third field in each cell titled 'offset,' but the problem is that the "Generate PWM" vi doesn't update to have an input channel for the new entry field I created. I'm not sure how to edit "Generate PWM" such that it will take another input line. (image illustrating this below)

image.png

 

image.pngAbove is "Generate PWM.vi" -- I've made an adjustment already: I added in that double/control (offset) to as the function generator has an input line for offset already. I don't know what parts of the VI determine the inputs it will take when used as a subVI in the larger "Cont Gen Dig.." VI I've attached. 

 

Any help or insight is greatly appreciated

 

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event

June 7, 2017, 7:26 pm
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Can someone help me out a little new with LabVIEW. I use an event case to control a tab control in the event case I have Booleans when valve change it change to the page it works but now the stop button has stop working. It all in a while loop. Delete the event and the stop will stop 1.PNGwork.

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leer varias tablas en excel para aplicar un control

June 7, 2017, 7:28 pm
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hola, como estan

mi inquietud es que tengo que realizar un control de angulo de ataque de un aerogenerador, para ello cree una serie de tablas en las cuales tengo un angulo predispuesto y vario la velocidad del viento para allar cuantas rpm genera, son aproximadamente 15 tablas, y el control debe de seleccionar buscar entre esas tablas el angulo que estoy utilizando y que velocidad de viento tengo, para asi darme unas rpm que comparare con un set point y  poder variar el angulo de la pala a uno adecuado. espero me puedan dar una idea de como hacerlo. gracias

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How to save recorded data on front panel Labview

June 7, 2017, 7:41 pm
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Hi,

i wanna ask about save recorded data when my program on process, for example :

oee.pngi have run my program for long time, then suddenly my power has shutting down, and then i want to run my program again and the value of program calculate rollback from zero again, i want to resume the last progres before the power was shutting down. how to resume it ? 

thanks,

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UI Freeze using Local Variable

June 8, 2017, 12:31 am
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Hi everyone,

I am fairly new to LabView. I have been trying to get my hands dirty the MatLab block and do some data processing with it. The VI is suppose to read a complete (.wav) audio file into an array; depending on whether the 'stretch' or 'play' button is clicked, the signal in the 'waveform' variable is altered/processed or played. 

 

The current behavior is that I can either initially

1. play the music

2. stretch the signal

3. stretch the signal then play the music

4. play the music and then stretch the signal

 

and then the VI just froze up. I understand that it freezes probably due to the 'locking interface option' when the event is being process... but I have yet to see why the event wouldn't finish processing...

 

Any help will be much appreciated. Thank you in advance!

 

(TIPS: if you going to run my VI, use a very short .wav file or it will take a VERY LONG time to complete my MatLab code when clicking the 'stretch' button).

 

Best.

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Is there any function which can detect if one USB port is available to insert to PC

June 8, 2017, 3:37 am
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Is there any function which can detect if one USB port  is available to  insert to PC?  Please help me .

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Web Publishing Tool Smartphone

June 8, 2017, 4:12 am
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Hello everyone, 

I have a problem when i want to control my front panel on my smartphone. I send to you a screen shot. I've just a blank vi. It's the same when I use an other computer. When I try on my computer (where the main Vi is), no problem, i can take control normaly.

I'm to the university, I've a box here and I don't know if my problem come from this.

 

Thanks.

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QMH - Enqueue Element Error Code 1

June 8, 2017, 4:13 am
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Hi, I have attached the VI I am having trouble with.

This is a rather simple QMH. It has an EHL and two MHL. When I run the VI in "Highlight Execution" mode no error is produced. However, if I run the VI at the speed it is intended to run at then there is an error produced in my EHL. Please note that I have implemented multiple error clusters so that is is easy to see where the error is coming from.

Hopefully, this is a fairly straightforward issue that I have somehow missed.

 

Any thoughts/suggestions on how to fix this error?

 

P.S. I have simplified this VI greatly from what it used to be - but it still does not work.

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Please convert VI from 2016 to 2015

June 8, 2017, 6:39 am
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rotate a ploted 3d graph around an axis

June 8, 2017, 7:26 am
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Hi ,
I am trying to make something like a CAM simulator , I started with a fixed object (cylinder) and a cutter (also cylinder) and i am trying to make the cutter to rotate around the axis of the cylinder and tangent to the top surface of the cylinder.
I attached the VI plus a video for what happened with me.

Capture.PNG

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LabVIEW Application Builder with LabVIEW NXG

June 8, 2017, 7:26 am
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With the latest updating Labview 2017 also came with Labview NXG 1.0.
My question is the enclosed version of NXG 1.0 capable of generating executable programs? Have not found the option so far.

 

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Mit dem letzten Updaten kam zusammen mit Labview 2017 auch  Labview NXG 1.0.
Meine Frage ist die beiliegende Version von NXG 1.0 fähig ausführbaren Programme zu erzeugen? Habe die Option bisher nicht gefunden.

 

René

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Event structure or producer/consumer

June 8, 2017, 8:35 am
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Hi everyone, 

 

I just started writing a program which is controlled by the user. 

 

The LabVIEW program will control a stepper motor and there will be a pressure sensor and force sensor connected to a USB-6008. There will be different options to run the stepper motor (which will be chosen by the user in the front panel by pressing different controls), at the same time values from the pressure and force sensor will be read and saved. 

 

For the reading and storing or values, I will use a producer/consumer. But what I am not sure is how to implement the events which are decided by the user. I am choosing between two options, but I am not sure about the pros and cons of each of them. The implementations I've been thinking about is:

 

1. Only use event structure.

2. producer/consumer. With an event structure in the producer and a case structure in consumer for the different controls. 

 

Is one of the structures better than the other? Then which one and why, what are the pros and cons?

 

Grateful for some discussions!

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How to control (Minimize and maximize) external application

June 8, 2017, 8:41 am
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I am trying to control an external window from my application.  I have done this years ago using the   "labview_win_util32_" but it doesn't seem to work quite the same on Windows 10.  Specifically when I give the VI "Minimize Window.vi" the program to minimize it gives an error. upon further investigation the "Get Window RefNum.vi" that calls the "user32.dll" returns 0 instead of a refnum which gives me the error.  It does not give an error on talking to he the .dll though.

 

  Has anyone successfully minimized an external program with 2016 and windows 10?

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Send Shell commands to Mate Terminal on Linux Debian through LabVIEW

June 8, 2017, 10:37 am
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Hello,

I am currently trying to make a LabVIEW VI on Linux Debian to run commands on the Mate Terminal. I know the proper shell commands to use on the terminal to connect an SSH server. Right now, I am in the process to try to make the process automated instead. I've used both SystemExec.VI and Pipes for this purpose. I know the SystemExec.VI requires a script file instead of sending the commands one at a time (if possible I would like to send commands one at a time to include prompts for the operator to verify the IP addresses. However, so far I've been unsuccessful since the first command is executed but then the session turns off before the next command is sent. I haven't attempted to use a shell script file yet, but before I start trying I just wanted to see if there was a better method to send shell commands to the Mate-Terminal (or any other terminal) in an automated manner. 

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VI to obtain last active pop up for all open applications

June 8, 2017, 11:07 am
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Hello Community,

 

I am currently designing a Labview VI using the Windows API functions through the "call library function node" block to first, retrieves the handle of all windows, then check through each window what it's most recent pop up handle was and then pass that handle to the get windows text API to display an array with the list of most recent pop up titles.  I am trying to then compile this into an .exe file and run another VI that uses the three button dialog block to create a pop up that I can close, but I can't find the pop up anywhere on the list.  The list of names that I get is about 500 long each time and I don't really understand why it's that long.  I am very new to labview and working with the Windows API functions so any help with this would be great.  I have attached a screeny of the block diagram along with the front panel showing what I get at the output.  Just to be clear my questions are.

 

1. Is my block diagram wired to correctly do what I want?

2. Why is the list of names so long at the output?


Thx,

Sam

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