Bug: Ci(x) and Chi(x) for negative values

January 18, 2015, 2:50 am

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Hi,

 

There are three problematic math functions in the Mathematics -> Elementary & Special Functions -> Exponential Integrals palette:

 

1) 'Cosine Integral.vi' and 'Hyperbolic Cosine Integral.vi' both return real values for negative input values. Neither function is defined in the real domain for negative input values, so should return NaN for inputs <0.

 

2) 'Dilogarithm.vi' is really evaluating Spence's Integral (as its icon says). The dilogarithm function Li2(x) and spence's integral isn't the same function, so it can't be both. Spence's Integral F(x)=Li2(1-x). The solution would be to a) Make the 'Dilogarithm.vi' really evaluate the dilogarithm function (and fix its icon), and b) To make an additional 'Spence's Integral.vi' that does what 'Dilogarithm.vi' does today.

 

Cheers,

Steen

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What is an embedded signal in labview?

January 18, 2015, 8:20 am

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What I have to do is this:

 

I need to Generate 2 2D arrays and make a subvi (done) but I need to do this with an embedded signal (I don't know what this is at all)

 

Then I have to multiply the 2D arrays and display it on an intensity plot (easy)

 

My main issue comes with the topic of an embedded signal, I have absolutely no clue what this is.

device instance path

January 18, 2015, 9:16 am

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Hi 

 

Guys, how do use LabView to read device instance path,

i do not think windows 7 has device instance id.

 

 

Best Regards

how to get smooth plot in graph

January 18, 2015, 10:17 am

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hello all 

 

 please refer the attached file for my question.

 

in it u can see two plots. the left one is on excel and the right one on labview. both the plots are for same data.

u can see the difference

i want to generate a smooth curve like that on excel. 

i tried various curve fittings like  polynomial, exponential, spline but was not able to get the smooth plot like the one im getting in excel.

note that the number of points in my data are only 5

LabVIEW executable with .NET controls crash, if operating system's regional format is Turkish

January 18, 2015, 11:57 pm

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Tested with Windows 7 and LabVIEW 2009 and 2010:

 

Crash is very easy to reproduce:

 

1. Go to Windows Control panel -> Region and Language -> In the first tab, set format: Turkish (Turkey) -> Apply change (doesn't need system restart)

2. Start LabVIEW (2009 or 2010) and create a blank VI.

3. From the .NET palette, drag the MonthCalendar to your front panel. In many cases it crashes at this point.

4. Save the VI and build an application exe about it.

5. Run the built application: it doesn't start, just crashes. From the Windows event viewer you can get some information:

 

Faulting application name: TurkishCrash.exe, version: 1.0.0.0, time stamp: 0x4b47dc79

Faulting module name: KERNELBASE.dll, version: 6.1.7601.18409, time stamp: 0x53159a86

Exception code: 0xe0434f4d

Fault offset: 0x0000c42d

Faulting process id: 0x%9

Faulting application start time: 0x%10

Faulting application path: %11

Faulting module path: %12

Report Id: %13

 

By searcing with KERNELBASE.dll and 0xe0434f4d you can get some information from web and it seems to be .NET related issue.

 

I'm wondering how the LabVIEW application developers survive in Turkey because of this problem..

 

Anyone noticed this, NI engineers?

 

BR,

Jani

 

OPC client cannot get value

January 19, 2015, 12:43 am

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There is a remote Matrikon OPC server.  Labview and DSC was installed on another PC(win7). 

 

In the LV project, a OPC client can be created and link to the remote OPC server. Items can be binded to shared variables. When run the vi with shared variables on the front panel. The tiny green triangle for each shared variable appear.

 

But the value of each shared variable is always 0. While the MatrikonOPCexplorer can link to remote server and refresh value automatically.

 

Any suggestion, thanks.

NI-Update: no connection to the internet since 115 Years!!!

January 19, 2015, 1:05 am

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I have just received the following message (I have the German version of NI-Update), saying NI-Update hasn't had an internet connection since 42023 days (or 115 years). I'm not sure if the message is entirely correct: I can still remember how about 70 years ago, after replacing some valve amps I also launched NI-Update. And I'm really afraid now, that all the updates for the past 115 years are going to be downloaded and installed at once.

Does anybody know if there is a way around this? Can I install the missing updates with at least 20 years interval?

 

Automatic Pause (through program) and Manual Resume through front panel Button

January 19, 2015, 1:20 am

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Hi, I am trying to implement a system which measures voltage and current for a varying source voltage at varying temperature. The program acquires 5 pairs of voltage and current data. The issue here is that the source voltage is varied by manually changing the value of the variable resistor. What I would like to do is somehow pause the program automatically once the loop (for acquiring 5 V and I data pairs) has completed. Then, after the user manually changes the value of the variable resistor (and enters the new value through a front panel indicator), the user should be able to resume the program through a front panel button like in this example: https://decibel.ni.com/content/docs/DOC-10792

 

Is it possible to implement this in LabView?

 

In summary: I would like to implement a system in which the program would pause automatically after a condition has been fulfilled, and can be resumed through a front panel button.

 

Thank you in advance for any help and suggestions. I hope I made my query clear. I'm not sure whether attaching the program would help but I included it just in case

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6024

January 19, 2015, 2:38 am

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I'm using PCI 6024 Daq device to measure volt, and temp, I've connected volt to AI0 to AI3, and I get every thing ok in voltage measurement,

 

but, I faild to read a thermistor sensor connected to AI4

I replaced the sensor with a decade resistor in order to try the connection, and I measure the voltage on a DMM after signal conditionning and it changes according to the resistance change, I measured the current (30 mA)  (I think the connection is ok)

 

I configure the channel on the daq assistant in labview

Read analog--> resistance --> thermistor with the configuation of excitation sorce to external: 30 mA , with no response

 

I've tried the NI example (RTD) example, also no response

 

can anyone help me in the pin connection and the labview daq assisstant configuration

 

thanks

table control

January 19, 2015, 3:03 am

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Buenos días,

 

Estoy utilizando un Event Structure para introducir datos en un Table control. En el caso mouse down selecciono la fila en la que quiero empezar a escribir  y borro los datos que pueda haber en esa fila, después voy introduciendo datos en el caso Key down? y convirtiendolos en mayúsculas. Paso de una fila a otra mediante la tecla return.

 

En problema esta en que si una vez escrita la tabla vuelvo a revisar los datos, la fila seleccionada con el ratón se borra como debe hacer. Al pasar a la siguiente fila con return los datos que habia se quedan seleccionados pero al escribir nuevamente no se borran y me aparecen los datos antiguos más los nuevos.

 

¿Cómo puedo hacer que se borren los datos al volver a escribir sin tener que suprimir cada uno de los caracteres? 

 

Un saludo

Supporting files outside .exe file

January 19, 2015, 3:21 am

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I have a labview executable which uses some resources.Currently I'm using the resources by giving file path.It becomes a problem when uploaded the executable and support files in the Internet and accessed from there.It loads only exe file and misses resource file.

Is there any option to embed resource files inside executable ?

Sound and Vibration toolkit download for LabVIEW 2011

January 19, 2015, 5:11 am

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Hi all,

Can anyboby please provide the link to download Sound and Vibration toolkit for LabVIEW 2011?

 

 

How to use different font styles in the same boolean text?

January 19, 2015, 5:48 am

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Hi all,

As reported here http://digital.ni.com/public.nsf/allkb/6BD344ACA4DEE20A8625692700737E16, it is possible to change font color, size or other font properties of a subtext in a string indicator. This can be applied to a caption too.

I'd like to apply this properties to a boolean text but it does not work. The boolean control has the Text.selectionStart and End property node but it does not appear to function.

 

Can you help me?

 

Thanks all

Adding multiple custom edited controls affects vi runtime

January 19, 2015, 7:09 am

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I have a problem with custom edited pointer slider. After adding two or three custom sliders (from one .ctl file) the while loop which is responsible for comunication with external measurment card slows down so much that application is unable to work properly. Sliders are indicators and there is no data connected to them. What is more, if normal sliders from labview pallete are added instead everything works just fine.

I already checked whether custom sliders affects CPU or RAM and there isn't noticable change.

Do You have any idea what can cause this problem? 

How to read register storaged in IEEE 754

January 19, 2015, 7:29 am

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Hi!

I need to build an application to read registers from my gauge. Application is almost finished but values i get on from holding register are different than values on my gauge (ex. i have voltage 230V on gauge, and values about 20k in application). Gauge stores values in IEEE 754 32-bit format and I have no idea how to read it to get correct value. I saw it's possible with using "Type cast", but i don't know how to configure it, I am totally newbie in LabVIEW. I will be much grateful if someone could show me a VI with reading from IEEE 754 option, or just tell me how to do it in detail (what to click, what to write, etc ) 

Sorry for my english, I hope I didn't make many mistakes  

Greets

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formula nodes

January 19, 2015, 7:31 am

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I'm using a Formula Node and my out put is always the number the same

Z= -4.08442104999969e-1*X+2.21688421e1;

the value of X changes

not sure what im doing wrong

 

thanks

Is it possible to use FPGA to modulate/demodulate LED communication?

January 19, 2015, 7:37 am

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Hi all,

 

I am looking for some technical assistance with a current project I have been tasked with.

The project requires the construction of a working Free Space Optical (FSO) link. Although exact distances have not been stated as yet, it is hoped to achieve a working prototype in the lab and then build from there.

 

To avoid the need for PCB construction and component soldering i was wondering if it would be possible to use a FPGA to carry out the modulation and demodulation of the light signal at the transmitter and receiver.  A basic block diagram of the idea i have in my head look something like this....

 

 

Transmitter
I/O Device (TCP/UDP) >>> FPGA BOARD (To modulate the data and drive a current to the LED) >>> LED ARRAY >>> FRESNEL LENS ------ free space-----

 

Receiver
------free space >>> PHOTOSENSOR/PHOTODIODE >>> FPGA BOARD (To de-modulate the light signal) >>> I/O Device (TCP/UDP)

 

 

 

Now i am sure it is probably far more complex than I am making out but this is just an initial idea. Thankfully we have until April to deliver the project so i have plenty of time for learning!!

Lauren

 

 

Any help is massively appreciated!!

Reshuffle / Interleave 2D Array

January 19, 2015, 7:51 am

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Hey guys,

 

Background info for context:

I know the answer to this is somewhere out there, but so far I have been unable to enter in the right key words.  I am building up an analysis routine where I am comparing monthly values by a category in which there are two "buckets" of information per month.  Ultimately, this will all be plotted on a graph to compare month by month values.

 

Question at hand:

I have built up a 2D array which I want to interpolate much like a 1D array.  If I have [x,y] structure where I want to interpolate the second half with the first, what is the quickest way to do this?  ie, my values would take the form [0, x/2, 1, x/2+1] while the y values would remain unmixed.  (Much like a sort function in Excel where you sort by a single column and every value rearranges based on the sort column.)

 

 

I am not a computer scientist, but have tried (probably poorly) to use the proper notation to help convey what I am looking for, but if I have not, please ask and I can clarify.  I am hoping to do this in the most efficient manner as these arrays can get very large.  I am also a big fan of the MGI, OpenG, GPower, etc. pallets, so if there is something already developed I can use, I am all for it.

 

Thanks for the help.

Variant to Data Object Class

January 19, 2015, 7:54 am

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The "Variant to Data" has that "Type" is a required input, according to the help documentation.

 

However, I can do a variant to data without using the type when the variant is an object and a Class Method is attached. Is this expected behaviour?

 

Also attached is a screen shot. The top loop used to have a "blue wire" method, which then became a child of the "brown wire" method. Since there is no type, the blue wire seems to have retained it's last colours. By duplicating the code, the new isntance has the correct colour. Both loops provide the same output,

I have been asked by my IT department how a LabVIEW application is secure

January 19, 2015, 8:02 am

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In general how does a standard LabVIEW application respond to these requirements:

The runtime environment shall not be susceptible to buffer overflows, SQL injection, LDAP and XPath injection, code injection or any other injection flaws. Malicious file execution and insecure direct object references shall be prevented at all times.