Quantcast
Channel: LabVIEW topics
Viewing all 67075 articles
Browse latest View live
↧

PXIe-6535 Digital Output only P0_L0

January 30, 2019, 2:34 pm
$
0
0

I am turning to help here as I have exhausted every search and example I can find...

 

I have a chassis with 4 PXIe-6535 Digital IO cards.  I need to output a pulse of 100us @ 300Hz (3% Duty) on 24 of the 32 channels.

 

These pulses need to be staggered delayed across the 4 6535's, however this is getting way far ahead from where I am currently stuck.

 

I have created several VI's for configuring and outputting the pulse, and I can ALWAYS get a desired pulse output on port0 line0, of each card.  

 

I cannot get the function to produce and output on any of the other channels in the card, no matter what I do.  I change the target line and run, and the Active LED on the slot lights up, but I cannot see any pulse when I measure the cable with a scope unless I have selected Line0.

 

In MAX, I can create a DigitalOut task for any of the channels, set to continuous samples, and always get an output - so I know the hardware is functioning. 

 

I have uploaded an image of one of the VI's that I created based on a search and example for this problem, and again this works great if I am choosing Line0.

 

Hopefully someone can point out the silly and simple error that prevents this from working on all the lines of the card!  Thanks in advance

 

↧
Search

Processing large amounts of Data from DAQ

January 30, 2019, 3:02 pm
$
0
0

So I have an application that gathers a lot of data from instruments (20 MS/s on three channels). I have been trying to figure out how to use producer consumer loops to process this data. The data must be separated into chunks of approximately 1.5 million samples to be processed. The location where the data needs to be separated is determined by a dll that I wrote which monitors two of the channels and finds where to split the data. My initial thought was to use a shift register to store the data and then have my dll figure out where to take the chunks, and then place the data in a queue for the consumer loop to process one chunk of data at a time. However, I am not sure is this is the best way to realize this.

 

Basically I have:

  • Data coming in from three channels (about 65000 samples at a time)
  • That data needs to be combined so that my dll can find where to split it into chunks
  • another loop should receive the chunks for further processing.

If anyone could point me in the right direction that would be awesome. I have been looking into circular buffers, the queue system, and shift registers; however, I am not sure about how to do this.

↧
↧

Regarding TIME STAMP Control in LabVIEW

January 30, 2019, 8:19 pm
$
0
0

Here i have attached which is having time stamp control,where i can mask time but when i click on control it is showing date and time I don't want time in that control,i have to set time once either that is 00:00:000 or 23:59:59.Later i have to change date.Below i have attached a vi which is having timing information control.If there is any idea to mask time completely please suggest me.

↧

generate voltage in myrio 1900

January 31, 2019, 12:13 am
$
0
0

Hi guys, i was trying to create a constant voltage (1.25V) in labview using myrio 1900. I tried few times but still couldn't make it. Can Anyone help ? 

 

 

Thanks in advance ！

↧

Error 200621, memory underflow NI USB 6212, Do not allow regeneration

January 30, 2019, 12:33 am
$
0
0

Hello.

I have a problem with error 200621. My apps are working properly, but sometimes ( 1/100 launch) this error occurs. I found some solutions here, but I still can not solve my problem. I need to keep the regeneration off.

Thank you for your help!

JJ

 

HW - NI USB 6212

↧
↧

Any recommendations on small cameras that work well with Labview

January 31, 2019, 1:39 am
$
0
0
I'm currently working on a project with my engineering club at college. The project focuses on air flow through a variable leak in a pipe. So I'm looking for a camera that can be connected to our National Instruments DAQ, controlled by Labview and is small enough to fit in a 2in diameter pipe. I know this is asking a lot but any recommendations help so thanks in advance!!!
↧

Create a custom project template with Packed Library dependency

January 31, 2019, 4:11 am
$
0
0

Hello everyone,

I'm currently strugling creating a new custom template project (http://www.ni.com/tutorial/14045/en/).

 

 A bit of context :

  • Project I want to create from this template allow the user to create a new plugin for an application --> building the project gives a packed library
  •  The project rely on a packed library that is used as interface between EXE and plugin

 

T

The project contained in ProjectTemplate directory as the following hierarchy

 hierachy.png

The lvproj opens correctly here.

 

First issue

If I try to create a new project from the Create Project window, I get an error 6

 

error6.png

 

CopyUserProject.vi has a password but path inputs type don't have path that exceeds 255 characters

I found a workaround removing the explicit link to the packed Library interface in the project. If this packed library is in the dependencies, project is correctly duplicated, but... see issue 2

 

Issue 2  

In the new project, the  packed Library interface is linked to the ProjectTemplate directory. I would like to change this link programmatically in order to link to my actual entire project. Do someone know how to automatically change this link ? ( Note that I know that even manually, this not something easy...)

 

Thank you for any ideas that could help me.

↧

VISA read functions make loops take wayyy more time than they should

January 31, 2019, 4:48 am
$
0
0

Hi,

I'm currently new to Labview and I'm actually experiencing a problem with my Program.

I'm using the Visa read function to read the inputs from my Lock-in amplifier.

Sadly my While-loop needs to wait for it each time meaning that each loops take more time to be done.

Any way to use a similar VI that takes less time to resolve?

By the way does VI read fuction wait for each machine input or does it simply return the old value each time it waits for a new one?

 

You'll find attached to this My VI. I highlighted the part that could cause this Problem.

Thanks for taking the time to read my message.

↧
Search

select letters from file and store them in an array

January 31, 2019, 5:06 am
$
0
0

Hi all,

 

I want to read out letters and numbers from a textfile and store them in seperate arrays. My file looks like this: -23,-33,""-15,-19"N", (and so on, so it's always two numbers and one referencecomment, which I want to have in the same row of the arrays) . So I've tried it with the Spreadsheet String To Array Funtion, but with this I'm only getting the numbers (because they are seperated with , ) I would like to have the two numbers in a 2D array and the referencecomment in a 1D array.

My idea is now to search the string for " and save the next item in an array, but there's than the problem, that I also need the empty spaces ("") in the array. Now I am quite uninspired and hope you can help me.

 

Thanks

↧
↧

generate analog output voltage in myrio 1900

January 31, 2019, 5:10 am
$
0
0

Hi guys, I am trying to generate analog output voltage in labview. Can anyone help me please.

↧

Flat sequence structure with While Loop

January 31, 2019, 6:25 am
$
0
0

Hi, this is a really interesting problem that I am facing. I created a flat sequence structure and it works fine with a New VI. But it does not work after integrating it with another While loop. I will attach both of the VIs to the topic.  

 

To make it clear, please run "Works.vi" file to see the Flat sequence structure that works fine. Then run "Does not works.vi" with an Arduino Mega. Then you will see that it does not work for the time I set for it and it only works like blinking. 

 

Best

↧

Generating finite number of pulses to move motor

January 31, 2019, 6:28 am
$
0
0

hi all,

 

I've created a VI which creates a finite pulse train, which is send to my NI-USB 6251 DAQ box.

The frequency, duty cycle, and number of pulses are input variables. The pulse train is retriggerable via a digital input.

 

Let's say i want to send initially 2500 pulses at a 1000 Hz; after this, i want to send 5000 pulses at 500 Hz.

The software does allow me to change the values but, it still deals with the initial values (2500 pulses, 1000 Hz).

 

I've tried different things, but i'm lost now. I think I'm making a beginners mistake, can someone help me out?

 

↧

Open SubVI from block diagram while code is running

January 31, 2019, 6:42 am
$
0
0

Typically you can open the block diagram of a SubVI by just pressing ctrl and double clicking it (on the block diagram of the VI one layer above).

But when the project is currently running a double click will open the front panel, but if you simultaneously press ctrl to get the block diagram you only set a breaking point. It is not such a big deal to first open the front panal and then switching to the block diagram, but still it would be nice to be able to open the block diagram immediately. Is there some way to do this in running mode?

 

Best regards

↧
↧

VISA serial interface works only in design mode

January 31, 2019, 6:52 am
$
0
0

This  VI does what it is supposed to do in design mode ( Its part of a project ). But when I build the project it does not work.  The Serial Port reference is via the control which has the right port by default. 

 

What could be wrong ?  Using LV2017 / WIN10 Pro / VISA driver 17

 

Simple Serial Query-Response.png

↧

Icon text not in main Block

January 31, 2019, 6:52 am
$
0
0

Hello,

 

For some reason my Icon text is not going into the main block

Capture.PNG

Any help on how to resolve this would be great

 

Thanks

↧
Search

Data precision in spectral measurement

January 31, 2019, 6:55 am
$
0
0

Hi guys,

 

I'm using DAQ assistant and Spectral Measurements to analyze a signal. I need the exact distribution between 49.8-50.2Hz but the both datas acquired from the "Spectral Mesurement" and "FFT Powerspectrum and PSD" seems to have a too rough datas and only power of the frequencies of integer is showed. Is there any way I can acquire more precise datas? I've heard of NI-RFmx SpecAn, will that be helpful?

powerspectrum.PNGBest Regards

 

↧

Transferring and manipulating data from oscilloscope to labview

January 31, 2019, 7:01 am
$
0
0

Hello,

 

I have managed to read the data from the 2 channels of the oscilloscope. The aim of my program is to store the data of each waveform in an array, zero pad the waveforms (add zeros at the end of the waveforms) and then multiply the elements of the first array (i.e. waveform) with the elements of the second one (or if the data is stored in one array then multiply the first column with the second one). Could you please provide me with any ideas. I am providing below the block diagrams and my code.  

 

Thanks in advance!

↧
↧

IEWebBrowser2 & IE11

January 31, 2019, 7:19 am
$
0
0

Hello everyone, I'm using the activeX IWEBBROWSER2 controller which natively uses IE7 even if IE11 is installed on the PC.
How can I use IE11 also from IWEBBROWSER2 within the labview development environment?

Thanks for your help Smiley Wink

↧

[myRIO] Voltage measurement to get analog signals

January 31, 2019, 8:26 am
$
0
0

Hello, I'm fairly new to this software and was wondering how (or if there are any similar tutorials around) I could make a code that measures voltages and gives analogue signals, and to use a hall effect sensor. 

 

Not sure how to begin this work, as I don't know what tools/components I should use with labview.

↧

PCR Temperature Control and Monitoring

January 31, 2019, 8:56 am
$
0
0

Hii, I am working on a project where I need to control and monitor the temperature with three zones respectively for amplification using pcr technique:

1) Denaturation - 95 C (2mins)

2) Annealing - 60 C (60sec)

3) Extension - 72 C (45sec)

 

This is for one complete cycle. And I need to run this procedure for n cycles. I am using the following components:

1) Peltier module for temperature heating purpose

2) DAQ 6002

For 3 different temp I am using only two peltiers  heating module and I am achieving third temp by balancing the two, you can just see vi file below, but I am not sure till what extend it will be accurate.

 

I am herewith attached the vi file. I request you to please do the needful and reply for the same. If you have the vi code for the above please I kindly request to share or upload it.

↧
Viewing all 67075 articles
Browse latest View live
Search
<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>