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LabVIEW topics



LabVIEW topics



Published: Sat, 25 Nov 2017 08:20:20 GMT2017-11-25T08:20:20Z

 



How to replace all spaces with tabs?

Sat, 25 Nov 2017 06:59:50 GMT2017-11-25T06:59:50Z

I wrote a program that reads a file and adds a number everytime the file has a tab. I want to make it so any spaces in the file turn into a tab and continues to add a number to the file. I can provide the program if needed, any help is greatly appreciated, thank you




Can't find NVIORef.dll

Sat, 25 Nov 2017 03:11:48 GMT2017-11-25T03:11:48Z

It‘s no problem to use the project in the attachment to build a installer, but when I install this one on a new computer without labview and run it, I get a error that can't find NVIORef.dll. How to fix it?




DAQ Assistant Acquisition mode N sample

Sat, 25 Nov 2017 00:20:23 GMT2017-11-25T00:20:23Z

Hi

 

I have created a LabVIEW program to collect and save data from the 11 sensors using NI DAQ. I have also synchronized LabVIEW with another software. I actually wanted to calibrated my sensors with another device. So I synchronized the LabVIEW program with its software. 

 

I mistakenly adjusted the acquisition mode to "N Samples" instead of "Continuous Samples". Now, I have finished my data collection and found that the number of samples is less than the expected amount. For example, I have collected data for 113 seconds and it was supposed to have 113000 samples but I have around 104000 samples. I may not be able to repeated data collection. Therefore, I need to find a way to recover missed data. 

 

I set the Samples to Read: 100 and Rate (Hz): 1k.

 

I have the duration time for my collected data. I can use interpolation method to recover the missed data but I do not know where I lost data. 

How can I find where and how many of samples that I lost?  

 

Thank you for your help.

Iman

 

 




Error -50103 How can I clear the task in main VI?

Fri, 24 Nov 2017 16:53:20 GMT2017-11-24T16:53:20Z

Helle everyone,

 

I want to use subVI's for gathering data from variant sensors, both digital and analog data. So firstly I have the VI's for all sensors independently working clearly and nicely. But when I simply tried to run them in the top-level VI it just didn't work. It gives "error -50103".

 

 http://digital.ni.com/public.nsf/allkb/EBF0B0F4542E402886258122004FB314 here NI has some solutions for the cases, I think my case is case 3 :

Using multiple SubVIs that run without any error independently, but generate an error when called from a top-level VI.
 
NI suggests that I should clear the task before I open it again in another subVI, but I don't know how to do that. If i can give reference to stop task and create task I could menage that I guess, but I don't know how to do that too..
 

 



Connect fluorescent microscope to computer

Fri, 24 Nov 2017 16:35:25 GMT2017-11-24T16:35:25Z

In our lab we hav new fluorescent microscope, but there is problem connecting it's camera to software we used before. Can I by LabView make soft to get signal from fluorescent microscope's camera.




Upgrade Issue

Fri, 24 Nov 2017 16:43:07 GMT2017-11-24T16:43:07Z

Hello everyone,

 

I come with this topic to present my recent issue in upgrading from LabVIEW 2015 to LabVIEW 2017.

Currently I am developing a RT Application using GOOP and Actor Framework.

The application was running smoothly in LabVIEW 2015, once I fixed many of the issues with memory, but after upgrade all my software to 2017, the application is behaving in a strange manner. (An actor recording data to TDMS and text file is eating up memory on every run)

I would like your help to point out the main topics in LabVIEW 2017 that are different from 2015. In this way, I could look more specifically into the behavior of some VI's or functions.

Thanks.

 

P.S. By the way, I did not upgrade, I am doing some tests to check the viability of the upgrade, so far not good




syn c modules on 9178 chassic

Fri, 24 Nov 2017 16:14:38 GMT2017-11-24T16:14:38Z

I need to acquire at low frequencies ie 10 samples a second. I can easily achieve this using daqmx example in help, replacing virtual channel with a task, i.e. 9205 ai all diff channels. However when trying to add another module like strain 9237, sample rate will default to 1.6ks/s. I also use 9238 modules. Is there any example to get all these modules to share sample rate, ?

 

Regards

 




Quadratic Programming Warm Start

Fri, 24 Nov 2017 15:13:59 GMT2017-11-24T15:13:59Z

Hi,

 

I would like to know how to provide the initial guess for both Lagrange multipliers and the solution. It says there warm start will use the previous one, however, I need the previous one in a shifted version since I am doing Model Predictive Control (MPC) and I am recalculating based on the fact that I have already implemented the decision u(k) so at the next sample I will be calculating u(k+1), thus both the Lagrange multipliers as well as the solution must be shifted and the final u(k+Nu) its duplicated like in the Real-Time Iteration (RTI) Scheme, otherwise is nonsense.

 

If anyone could point me in the right direction I would appreciate.

 

Regards,

Oscar




How do I add an element to an existing cluster. I thought it would be easy!

Fri, 24 Nov 2017 15:05:31 GMT2017-11-24T15:05:31Z

Hi all. I have inherited a sub vi and need to add an element to an existing cluster of 8 elements. I have looked at all the examples I can find but can't figure it out. Firstly I don't understand why the front panel has names on the indicators, Respiration, Pulse, Sync and yet the Bundle by name function has "Data channel 1" etc.

I need to add an indicator with an array of 4 byte numbers called "Time" and add that, to make a cluster of 9 elements. I thought it should be relatively simple but I'm stumped.

Thanks for any advice.

Andrew

 




Rio 1900 and Arduino Modules

Fri, 24 Nov 2017 14:35:54 GMT2017-11-24T14:35:54Z

Hi! I want to know if i can use arduino modules (LCD Screen etc..) on my Rio-1900?

Our group is planning to build a standalone ECG using myRio. We need to show the output waves on a standalone screen and not using LabView.

 

Thank you! All inputs will be highly appreciated

 

jamescpe




Using the C# dll to update the .NET PictureBox causes memory leak

Fri, 24 Nov 2017 13:16:10 GMT2017-11-24T13:16:10Z

Hi,

I use a C# dll that acquired images from a camera and updates a .NET PictureBox in a VI. The .NET PictureBox reference is provided to the dll at first call. Everything runs smoothly, except that there is a memory leak which is cause by updating the .NET PictureBox. Below is the code in C# that .NET PictureBox and disposes the old image.

Bitmap bitmap = new Bitmap(grabResult.Width, grabResult.Height, PixelFormat.Format32bppRgb);
/* bitmap manipulation code */

// Assign a temporary variable to dispose the bitmap after assigning the new bitmap to the display control.
Bitmap bitmapOld = pictureBoxe.Image as Bitmap;

// Provide the display control with the new bitmap. This action automatically updates the display.
pictureBoxe.Image = bitmap;
if (bitmapOld != null)
{
	// Dispose the bitmap.
	bitmapOld.Dispose();
}

I would appreciate any suggestion on how to solve the issue.




Writing Row range from labview to excel

Fri, 24 Nov 2017 11:36:40 GMT2017-11-24T11:36:40Z

Dear all,

 

My application needs to read some columns of excel sheet row by row (Eg. Columns A to D) then process on it and write output in specific columns of that row (Eg. E to H). I could able to read & process the data but facing the problem in writing out put data back to column range of same row. To more elaborate the problem, Suppose my Column A is having some values and column B is having some values. I want to read these columns row by row and write addition of these number in column C of respective row. 

 

Can anybody help on this. I can write to excel but finding difficulty in writing to specific column of  same row.

 

Thanks & Regards,

Gajanan




Alternative for the Quotient and Remainder function inside an SCTL

Fri, 24 Nov 2017 11:12:49 GMT2017-11-24T11:12:49Z

Hi NI community,


I recently started working with LabView and am trying to design a switch port selector algorithm for an FPGA. This includes a counter with a total number of repetitions (e.g. 100) which needs to switch on every Nth (e.g. every second) repetition.

To implement this, I used the Quotient and Remainder operation after the counter, placed within an FPGA source clocked Single-Cycle Timed Loop (SCTL). Since this function is restricted to use in a SCTL, I am trying to find an alternative which won't influence the outcome. Any advice is highly appreciated.

Thanks!




Measure the rate of a signal in real time using Peak detector vi

Fri, 24 Nov 2017 10:35:55 GMT2017-11-24T10:35:55Z

Hi, 

I have a question about how to get frequency rate of an analog signal using peak detector in real time. As i know, to get the frequency rate we have to measure peak to peak time inteval, but the peak detector VI just gives the index of each peak. so to have its time, we need a formula between position and time intervals.

I appreciate your help with any suggestion , an idea or explanation on how to do it.

best regards 

thanks




Data acquisition with Labview FPGA

Fri, 24 Nov 2017 09:31:15 GMT2017-11-24T09:31:15Z

Hi all, 

I'm new to labview and have some problems with the application I'm trying to develop.

I have an NI SbRio9636 to which I have connected a laser sensor. I'm running the program on my laptop, which is an Acer Aspire F15 running windows 10. I have three VI's running on the board, which are attached.

- FPGA.vi is running on the FPGA-target of the board. It defines which inputs/outputs of the board I want to use in my project. 

- interface_FPGA assigns these inputs/outputs to different variables that I can use in other VI's in the project. 

- werking_bordje is used to record the data. I want to save some signals (time, laser_voltage, position_counter and the sine wave) to process them after the program is finished. The program is pretty simple: I compare two signals and determine the direction (forward or backwards) and action (take step or do nothing) my motor has to take. 

The problem I'm encountering is the following: Every 512 loops, my program starts to miss iterations, they normally start around the 2048th loop and then repeat every 512 loops. At the start the period of these missed iterations equals about 2 ms, but the further along the program goes the period of such a missed iteration grows (27ms for the 53248th iteration). I have tested this with different sample frequencies, they don't seem to influence the problem. 

I figured the problem may have something to do with the auto-indexed tunnel, where it is "full" every 512 values and has to "grow", but I cannot find a lot of information about it on the web. 

Any help as to what may cause this "buffer-problem" or how to overcome it, would be greatly appreciated. 

Thanks in advance!

Oliver




Problemas con estructura event. Problems with event structure

Fri, 24 Nov 2017 08:42:52 GMT2017-11-24T08:42:52Z

Moved to another board



Rigol MSO4024 write just one sample data when external trigger event occurs

Fri, 24 Nov 2017 08:21:17 GMT2017-11-24T08:21:17Z

Is it possible to setup a Rigol MSO4024 oscilloscope to just measure one sample when an external trigger event occurs?

Additionally, I want to read just that one sample in LabVIEW.




Report Generation using word template, the application does not find template file

Fri, 24 Nov 2017 06:51:54 GMT2017-11-24T06:51:54Z

Dear Folks,

In the middle of completion of a project, im stuck in what seems like a simple problem maybe..

I'm creating word report using a template..it works fine in the development system.

Have MS word 7 version on this system.Have included LVclass andNIreport and template in source files- always included..build fine and runs fine on the development computer

 

In target system,

it says unable to find file.. im assuming its template file as the diplay shows path for the development system's.. how ever the template file is present in data folder fo the application..

One target system has MS word9 version and another one has MS word 16.. unable to figure out whats the issue.. 

Attached are screenshots and the vi..Any help is greatly appreciated..

 

Thanks,

Palvi




Running a Labview rtexe from linux beaglebone manually, not on startup

Fri, 24 Nov 2017 03:52:06 GMT2017-11-24T03:52:06Z

So i have configured 1 main.vi and subA.vi and subB.vi . the main.vi runs initially and calls subA.vi , next the subA.vi calls the subB.vi , then subB.vi calls subA.vi, and on forever until stopped.

I'm using the beaglebone device and would like to have some code calling the main.vi explained above.

Currently, it works when I deploy it to the target as startup, but i would like to not have it run on startup, but on a specific trigger or running a code.

Is this possible?




Removing baseline drift of ecg signal

Fri, 24 Nov 2017 01:17:43 GMT2017-11-24T01:17:43Z

I am making a program with ecg signals with noise.  Every time I filter the signal using the lowpass butterworth filter, there is still a baseline drift at the beginning.  Any suugestions on how to get rid of it?