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Need help with Pt by Pt derivate

May 11, 2017, 2:32 am
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I'm using a Ni usb6216 to acquire the position value from an rotary encoder. Since I'm new with labview I started from the encoder example " Counter - Read Encoder " given with the nidaqmx driver.

It works and I can read the position properly, but I now want to derivate the signal to obtain the rotation speed.

The point to point derivative block doesn't seem to work, cause it's output is still the position value divided by the "dt" value.

I don't know what's wrong, maybe it's some basic knowledge of lab view I'm missing.

 

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Connection of PT100 to NI9217

May 11, 2017, 2:44 am
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So I've got a couple of PT100 RTD's connected as in the attached image and I'm struggling to get both of them to read correctly at the same time. When I just connect the Gauge PRT at a 3 wire with the blue, yellow and white wires it works, and the same with the Fluid PRT using the white and two red wires. When I connect them both to two channels on the ni9217, one reads as expected but the other is reading as if it is short circuiting the PRT (-244 degrees C which is about 0 ohms from a PT100). I cant figure this out and have tried several different orientations. Also, surenrly given the orientation of my two RTD's, using a 1mA excitation for both would give me a 2mA excitation for the second gauge given current laws (1mA and 1mA into a node gives 2mA out). Also, Labview will only let me use internal excitation and complains every time I try to select external or no excitation. 

 

Any ideas of how I could make this read as expected?

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application multilingue labview

May 11, 2017, 3:35 am
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Hi,

how i can make an application multilingue in labview?, I want the user to choose his favorite language in the same window, 

 

I am looking for a tool that allows me to extract the references or the terms that excise on the interface, so translate and replace them on the same interface?

 

thank youuu for your help .

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Comparing elements of array with previous ones and insert index of elements where v[i+1]

May 11, 2017, 4:14 am
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Hi,

i'm new to Labview. I'd like to get some helps to solve this kind of problem. I've got an array of integer in input and i must compare every element with previous one. If the element in i-th position is less than previous(i-1 th) then i must insert index of this element in another array in output, else if the element in i-th position is greather than previous(i-1 th) then i must insert zero in output array.

 

Example

Array in input=[1,36,2,3,43,6,8,1]

Array in output=[0,2,0,0,5,0,7]

 

 

Any helps would be kindly appreciated. Thank you so much.

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Problem with extracting column from 2d array

May 11, 2017, 4:59 am
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Hi all, I have problem with extracting columns from 2d array and saving it to the cluster which contains 5 arrays. Could you tell me what am I doing wrong? I attach my project to this post. The txt file has 5 columns and 6 rows. Also how to make it possible that the 1st row will be string and the others arrays of doubles.

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Locating Express VI Components

May 11, 2017, 5:12 am
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I created several express Vi to control devices on a bench test.

These express Vi allow to easy program the device. ( power supply, oscilloscope, generator .... )

When i modify the source code or the config code of the express vi, the modification is not deployed in my Labview program.

My Labview program keep the previous version of the express VI.

 

In this NI help lavbiew 2016 document :

https://zone.ni.com/reference/en-XX/help/371361N-01/lvconcepts/express_vi_location/

 

We can read :

 

"When you save a VI that contains an Express VI, LabVIEW saves the Express VI inside the VI. When you open the VI, the Express VIs within it load from the same file as the VI and not from the source VI file of the Express VI. Therefore, you must place all the functionality of the Express VI in a subVI that you can update as necessary."

 

Do you have an example ?

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siguiente fila string

May 11, 2017, 6:12 am
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DAQ

May 11, 2017, 6:30 am
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I want to create a virtual simulator

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Wifi Module of NI MyRio 1900

May 11, 2017, 6:53 am
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I want the detail of wifi module used in NImyrio 1900.I had to defend it  but not found its features and details.

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Start Button and User Inputs

May 11, 2017, 8:02 am
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I would like to create a start button for my VI for when I export the program to be used without being able to edit. 

 

I know that I can select start VI upon opening and I have then created a start button by using a while loop where the stop button is linked to the start button. (So loop finishes and VI continues once the stop button has been pressed). However, my issue is that my VI has user inputs that are required and when I press run and then try to change the user inputs before pressing start, these are not registered. 

 

Is there a way to make this work so that the VI can be started via opening and user inputs can be changed before pressing start?

 

Thanks

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I Only Want to Plot the Entered Data - no 0s

May 11, 2017, 8:05 am
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I'm currently reading data points from a text file and plotting them to a waveform graph.  It's working perfectly -except- in instances where there is no data, the graph displays 0 (causing lines straight down to appear in my actual data).  I'd like it to not display anything when there is no data.  Is there a way to configure it to do such?  I'm brand new to LabVIEW.

 

Thanks

Sarah

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project of automatic monitoring for greenhouses

May 11, 2017, 8:25 am
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my project is about automatic monitoring for greenhouses using labview8.6 and I need helping because I faced some problems with no time,,

I have some broblems in blocks and with DSC Labview,,

Any one can help me????

Thanks very much,,

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project of automatic monitoring for greenhouses

May 11, 2017, 8:26 am
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my project is about automatic monitoring for greenhouses using labview and I need helping because I faced some problems with no time,,

I have some broblems in blocks and with DSC Labview,,

Any one can help me????

Thanks very much,,

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Compiling FPGA code numerous times has different results

May 11, 2017, 8:27 am
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I have been experimenting with compiling my code on different computers, virtual machines, and cloud compiling. Using the exact same code, I get different results...most compiles fail (usually timing violations) with a few successfully completing.

 

I don't really understand why this happens...digital computers working with the exact same code...compiling should give the exact same results.

 

I have burned probably 10 hours with this trying to get code to compile, which compiled 6 months ago (same software versions).  When it did compile w/o errors, the code was downloaded and worked perfectly.  I added a constant to the diagram, then deleted it and accidentally saved the code...LabVIEW wanted to recompile...since my code was already running, I didn't need it compiled, but I did it anyhow...which failed.

 

Now, I'm characterizing this some more, burning another 20 hours by testing on different computers, multiple virtual machines, and cloud compiling.  I am 100% confident it's not because I am pushing the size limits of the FPGA since I cut out 66% of the code and it had the same problems.

 

Has anyone else seen such odd behavior?

 

BTW, LabVIEW 2012, all software loaded from 2012 Developer Suite 1.

 

Thanks,

 

Todd

 

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find derivatives of mathematical function and visualize on XY plot together with mathematical function

May 11, 2017, 8:50 am
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Hi,

this is the first time i use labview and i'm a beginning developer but i'd like to create a VI that receiving the formula of mathematical function(exponential, logarithmic, sine, cosine, tangent, polinomial, exc) find the derivatives of these function and plot on XY graph either function either function's derivatives.

 

If someone can help me, i really appreciate.

 

Thank you so much

 

Giorgio Massaro

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Controls in MultiColumn Listbox

May 11, 2017, 9:02 am
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Hi everyone,

 

I've found an example online of how to select a row and place a checked box beside it  in another column for a listbox.  I see how they used the properties of the listbox but I don't see these properties for the multicolumn listbox.  Could anyone show me an example of how to do this for a multicolumn listbox?  I thought it would have been very similar.

 

 

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Compact Rio 9067 - unable to set FPGA interface

May 11, 2017, 9:12 am
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Hi,

i'm trying to run a vi on the FPGA of my CRIO-9067. For some reasons I fail to understand, every time I try to run the vi, as soon as the loading window "preparing for interactive executions" pops up, another pop up window opens basically telling me that the chassis is in "scan interface mode".

 

However, when i go to the properties window of the chassis, the option "FPGA interface" is properly checked.

 

In my opinion something is wrong with the CRIO, since after I experienced this problem I developed another project on another device (CRIO-9075) and everything work fine.

 

Has anyone experienced something similar?

Thanks,

Luca

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i need help

May 11, 2017, 11:37 am
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Hello guys,

I hope you can help me.

 

I want to sum all of price's codes. the input is "cod de bare" which changes while running (manually). I have tried autoindexing the  prices but the output is an array with only one code.

When i run the program i'm changing the value of code (1234,1235, etc) and at the end i want to sum all of the prices for that codes.

 

Thanks !

 

 

 

 

 

 

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Reuse Class update methods in project

May 11, 2017, 11:59 am
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Hello,

 

I have an OO question.  I want to have a common reuse class.  I have this reuse class in multiple projects.  Lets say I add a method to the Reuse class.  How do I get the new method into the projects that use the reuse class?  Do I have to manually add the method to my class in every project that uses the reuse class?  Is there way of automatically loading classes from file that may have methods added to them?

 

Thanks

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XY Graph X-axis Manipulation

May 11, 2017, 12:34 pm
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I'm trying to create the NC curve graph as attached in Excel.  I just can't seem to get the X-axis to show the values as depicted.  I'm using an XY graph in LabVIEW.  Does anyone have any suggestions?

 

Thanks.

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