I have 100 data files written using the 'Write waveforms to file.vi', each of which is 5MegaBytes. I could concatenate all of them, and the final file size is 500MB. LabVIEW shows an error that file is too big to read when I try to display it using waveform graph. Please let me know how I can load and display the concatenated file.
↧
How do I read big data files?
↧
LINX I2C Problem for communicating Raspberry to Arduino
Hi, I was trying to communicate Raspberry PI 3 with Arduino UNO via I2C using LINX 3.0. I want to send 40 byte length command to arduino and receive 16 byte data length from arduino almost in the same time (I know I2C is half duplex so I do it sequentially)
The problem is sometimes I get an error message either from LINX-I2Cwrite or LINX-I2Cread. I assume that this problem appears because the I2C bus is too busy to handle such a lot of data traffic. Any help would be very appreciated 
here is my VI snippet
is there any mistake with that? i have tried to change the delay time to 200ms and it works fine, but I need faster response (as fast as possible)
I'm using:
Labview 2014f1
LINX 3.0
Rpi3 with Updated Rasbian
Arduino UNO
↧
↧
simulation of three phase induction motor using LabVIEW
I don't have any basics about Labview, can i have any lecture note regarding on LabView lessons
↧
String concatenation within a loop - Optimisation / best practices
Hopefully someone can help me with this :
What optimisations could be made to the following code snippet to improve performance (reduce memory thrashing due to string concatenation etc.)?
This is mainly just for improving/learning more best practices and applying them in the future.
I would like to keep the tags and delimiters easy to change.
The output is an array of strings that look like this:
X:1.0000,2.0000,3.0000,4.0000,5.0000,6.0000;\n Y:0.00,0.10,0.20,0.30,0.40,0.50;
I've scoured the internet and forums for this topic and found a post about preallocating an array of uint8, but can't find it now.
Thanks!
↧
Data Acquisition without the NI-DAQ
I have a few queries regarding my beginner programming knowledge. I am a month old with LabView and my task is to acquire data from 1or more oscilloscopes, Temperature amp, Acceleration sensors and further more. I have to create a Data Acquisition program which gives me an output as I have mentioned below in one of the attachments.
For this I do not have funding to purchase NI-USB which uses NI-DAQ which teaches me how to solve the above easily. I tried building a program with the resources I have and I need some reviews about the same. The program does not show an errors but when I run it it does not give me any values. What am I missing. Please help me.
I am still learning so I do not mind if you state some obvious mistakes in the program or correct me.
↧
↧
Two way communication with parallel loops
Hi guys.
I'm working on a quite simple application. It's basically a test sequencer based on queued messages and I would like the UI to update after each test. I am trying to use two parallel loops, the first one handling all the UI events and queueing test cases and the second loop just dequeueing elements and running corresponding tests. What I cannot seem to accomplish is communicating back to the UI from the loop running tests. If I could trigger an event when an element is dequeued I could update the UI based on that, but I don't see a way this could be done. Initially the tests that are to be run are read from a table.
I could do a dirty solution with timeout event and comparing queue size to the initial test cases array size, but I feel like there should be a better way. Any help would be appreciated!
I am attaching a picture of my code to give you a better understanding.
↧
sick lms 100 output front panel
Hi i am working on sick lms 100 laser scanner. I am able to communciate with all the stuffs and run the program in labview. My final output is shown below but the problem is as far as i know, the laser scanner gives the distance and angle. The distance should be in mm but i am obtaining the array of distance of huge unit which is not correct. Can anybody explain me, why i am obtaining this result?
↧
Wemo LabVIEW Toolkit Demo with ESP8266 WIFI board Wemo emulator.
Here is a video that shows the latest two internal projects coming together.
↧
Shock Response Spectrum to Acceleration-Time Data
Hello everyone,
I can calculate SRS (shock response spectrum) using "SVT Shock Response Spectrum VI" of acceleration-time data,
But our customer want to convert shock response spectrum to acceleration-time data. How can I convert ?
Regards...
↧
↧
A huge set of values to array
Hey,
Hopefully someone can help me with my problem, I cant seem to find a proper solution. I have a very big .txt file with pixel values (7digit), one value per row, 170.000² rows. I want to create an array using these values, the dimensions have to be 170.000x170.000.
I want to export my array to excel, as a table or to a Bitsream Data, to further convert it to a picture or heatmap.
The Problem is, that the array overloads my RAM and I can't seem to find a proper solution to split the storage needs, because the "read from txt" vi doesn't allow me to set an offset, it would always start reading at the beginning.
I hope I specified my probelm good enough, thanks for any help.
↧
Create a 3D plot of stacked 2D plots
Hello,
For my research I am used to read experimental files, which are basically .lvm files with five columns. I use labview to trace 2D plots of column 2 (signal) vs column 1 (frequency), which is very simple.
During an experiment I save a file after each seconds, so after an experiment I have several hundred files (let's say, n files). Because the frequency span doesn't change during the experiment, the column 1 (frequency) is always the same for all files. The only changes are the title of the file (which is the time), and the other columns including column 1.
I know how to trace column 2 vs column 1 of file 0 to n on the same 2D plot, but I don't know how to distribute the 2D plots on a third axis to make a 3D plot.
In summary, I need to stack column 2 vs column 1 2D-plots to create a 3D plot like this : 
Where X would be the frequency (column 1), Z the signal (column 2), and Y the time (title of the file).
Can someone give me an example of this kind of 3D plots ?
Thank you very much
↧
DAQ by USB-6008
Dear sir,
I have an DAQ experiment by using USB-6008 and current transducer, I expect an AC current waveform can be obtained. However, I am confused that the 6008 box converts my AC current signal to DC signal, I cannot recover the orignal AC current waveform from the labview, how can I solve it?
↧
Visa error in exe build
Hi all,
I’m having some difficulties with running an EXE file which returns the error “VISA Flush I/O Buffer in TSI 4000.lvlib:Initialize.vi->Flow v Pressure Test 2.vi” on the EXE file I created. The VI runs smoothly using full Labview 2016 on the same machine without unplugging any of the instruments.
I have been using the application debugger to compare the two different programs and have identified an issue with the Visa registration as follows:
From probe 19 placed on the EXE file there is some missing Visa information (C.F. Figure 1 and 2 for probe comparison).
Figure 1: Output from probe 19 (exe file). (please see attached Picture files)
Figure 2: Output from probe 18 positioned at the same location as probe 19 (.VI file).
I have tried including the visa information in the build using “Method 1: Including the NI MAX Hardware Configuration” described here: http://digital.ni.com/public.nsf/allkb/80F2165E774B51FB86257CAC006E81A9
But this didn’t seem to work.
|
Further information:
Figure 3: Front panel visa information (EXE and .VI are the same)
FYI, this is a program which was written by somebody who has recently left the company so although I have gone through the program I may have missed something simple.
Thanks for your help.
↧
↧
PID VI
Hello!
I'm having trouble finding the PID VI in my FPGA LabVIEW module, as in here:
https://zone.ni.com/reference/en-XX/help/371599L-01/lvfpga/control_palette/
I can see the other two VI (Matrix*Vector and 3-Phase PLL), but not the other one. There is a blank space where I would expect it to be.
What can be the cause of this? Old version maybe?
↧
Deploy Update Vi express
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.
The Express Vi has not the same behavior as Sub Vi.
Where is the cache where is located the vi express used in my labiew program ?
I have to replace the old vi express by the new manually.
Thank you for your help !
↧
USB Camera ignoring imaq dx attribute set- sporadically.
I am cycling through four USB webcams, and capturing a frame each time I access a camera. I set the focus and exposure prior to capture with an imaq dx property node. As a forward note, I'll add that this phenomenon happens independently of the capture being Grab or Snap- in other words- this happens in both cases.
As I cycle through the cameras, sometimes all four will have successfully changed their exposure- sometimes only three- and sometimes none of them will have changed their exposure. I've placed waits in the flat sequence I am using (to wait for the exposure to change), and no amount of time seems to help. I hesitate to write out every combination of setup I have attempted to rectify this "sporadic exposure reaction", but it's been a couple weeks of trying things on and off.
Currently, the system is setting the attributes twice and grabbing the image twice. Saving/using the second grab to run through an algorithm. I will attach the VI; however it is in LV16 so, I'll throw in the screencaps, as well.
If anyone has had this issue/knows what I'm doing incorrectly/knows this is a common issue with usb cameras and the imaq dx drivers, please let me know!
↧
How plot a quadratic function using slide bar as x values?
Hi, I'm a learning user of LabVIEW. I would like to graph the function y(x)=x*x, but using the values of the slide bar control as x axis in a while loop. I want to graph the y(x) function as a continuous line and a different cursor to highlight the value of the slide bar. I know that using property nodes the maximum and minimum values, as well as the increment of the slide bar can be fixed. However, I haven't found useful examples online. I've attached a screenshot of the desired graph (edited using paint).
↧
↧
[LabVIEW Bug Report] The Specified Device Name is Invalid
I'm not sure if this is old hat, but it was the cause of some recent frustration on my part. I was creating several thousand files based on common stock names, when my previously working program started to hang suddenly, at apparently the same point. The running LV 2014 VI never recovers, the Stop button becomes non-functional and I have to kill it via the Windows Task Manager. It turns out a new name, "PRN" came up in the database I was using to create these new files from. Investigating, I attemped to manually create the file, which resulted in my Windows 7 Professional system indicating "The Specified Device Name is Invalid". Investigating the Windows error, I found on line that "Windows cannot create a file or folder named any of these keywords : CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9". Probing on the diagram, I find the Open/Create/Replace File executes without output error - just LV hangs indefinitely when it tries to create the file named PRN.
So, what are the chances anyone (but me) is going to create a file using these particular names? Still, I think LV 2014 should have handled it in a better way. Of course, I dont know if a later version of LV fixes this "hang" from happening. Hope this helps someone here.
Whomever "PRN" is, they're going to be glad they picked that ticker... On the flip side, all Windows users creating stock ticker named files are going to remember them!
↧
Idea for idea exchange: move/copy file progress info
I've got an application to publish test software (multiple large test libraries) over a network, and the large file and size and slow transfer speed begs for a progress bar.
In Windows, file move and copy will produce a progress dialog if the time to complete the operation exceeds a second or two. This behavior can be recreated in LabVIEW by using read/write from binary file and transferring small chunks of the file (see http://forums.ni.com/t5/LabVIEW/Using-Progress-Bar-when-reading-binary-files/m-p/313390#M162287) but this is a bit of reinventingf the wheel, and gets complicated when copying directories.
How coudl NI provide an asynchronous update of file transfer speed and progress for the Move and Copy file primitives? Would this be worthy of the idea exchange?
↧
Updating drop down menu, the menu will be updated based on values in an input array
I am trying to make a drop down menu that will display a list of values. The menu will be updated based on the parameters of another array.
↧