Moved to Academic Products board
↧
LVDT sensor connection NI myDAQ
↧
Increasing the acquisition speed for my application
Hello,
[Application explanation] I am trying to write a code that performs delayed-feedback control. To do so, I need to measure data produced by a very fast system (the system operates in the range of tens of kHz). The control scheme requires me to subtract the input control signal at time (t) from the output of my system at a previous time (t-tau), all the time.
To do this, I need to acquire the system's output at a very fast rate. However, because of the nature of my application, I cannot rely on acquiring multiple samples at the same time using the DAQmx Read vi.
[Current system] By acquiring 1 sample per loop, I am only restricted to around 1000 samples per second. Is there a way for me to increase this rate to 10,000 or even 100,000 samples per second?
↧
↧
Digital Output on an FPGA
I am currently using the PCIe-7842R FPGA, and I am trying to control an acoustooptic deflector via a direct digital synthesizer from AAOptoelectronics. The flow of my setup goes FPGA->connector block->DDS->AOD. I have wired up my DDS to the connector block using the pinout diagram provided, and have written the simple code attached to this post to control the DDS...it runs and compiles, but does not actually control the DDS. I have attached an excerpt from the DDS manual as well, and any advice on why my code isnt working would be much appreciated!
↧
Tone Measurement frequency resolution
Hello.
I want to measure frequency of mains very precise in real time.Signal is acquired through PCI-6014. I would need a resolution at least 0.1Hz or better (0.01Hz).
For tone measurement general recommendation is to sample signal at 5-10 times higher frequency and to have at least 3-5 signal periods for valid frequency measurement. What that means in math sense? What would be resolution of FFT implemented in Tone Measurement vi? For regular DFFT frequency resolution is equal to fs/N. So if I want resolution of 0.1Hz in spectrum does it mean I would need a 10 seconds of sampled data? If so , is it possible to acquire 1 period of signal and then fill rest of signal with sampled values until 10th second. When this is done with zeros it is zero padding
in DFFT and with this we can not get better resolution. I am thinking to do padding with allready acquired samples and just repeating them until I have wanted signal length so I can get better resolution of frequency components in “real time” and not waiting and sampling 10 s of data and then calculating spectrum of signal.
thank you
↧
Document not a readable LLB
Hey All,
I've been working on this project (Coincidence_rs232(4_5).llb) for a bit, and today i tried to bring it in to another project. Upon doing that (left click > select a vi...>click on LLB), labview told me that (file_path) is not a readable LLB. I then tried to open it by itself, and got the same message. It was created on the same computer I am trying to open it on. I cannot even upload it to here because the site tells me "The attachment's coincidence_rs232(4_5).llb content type (application/octet-stream) does not match its file extension and has been removed." When I open the file's properties, it is listed as a LabVIEW LLB (.llb). Cannot find anyone else having the same problem, so I would appreciate any help. Let me know if I need to provide anything else. Thanks!
↧
↧
Exec application revision
Do I need to rebuilt the application and installer when the hardware has changed.
Details:
I have an application that I am working on for a customer. The application includes four USB-6001 modules. I have sent several revisions to him by providing him the Configuration file, the .aliases file, and the application file. It is close to being completed.
The customer wants a 'stripped down' version that only uses one USB-6001 module. I sent him the new 'stripped down' version and he complained that some of the buttons no longer work. The problem may be on his end, but I was wondering now that I am only using one USB-6001, do I need to include a different installer? Is the DAQmx configuration included in the application file or the installer file?
↧
Draw Circle by Radius bug with 1 degree arc
Hello,
I've run into a bug in the Draw Circle by Radius / 2D Picture Control (reproducible in LV2018 32-bit and LV2019 32-bit).
If the radius is set small (<30), the line width set to a larger value (5), and the circle arc set to 1 degree, a full 360 degree circle is drawn in the picture control.
If the radius size is increased above 30, a 1 degree arc renders as expected. The bug will appear for different combinations of radius and line width, but in general a larger line width and smaller radius will cause the bug. I searched around and couldn't find any reports of this issue. Is it a known bug?
The workaround for now is an XY graph to plot a circle, or two concentric circles with one plot filled to the other to achieve thicker line widths.
↧
Axis multiplier in Waveform Graph will autoscale limits when autoscale is disabled
Hello,
I have a waveform graph with both autoscale and loose fit disabled on the Y-axis. If I change the Y scale multiplier using a property node, the upper and lower limits of the axis are automatically changed, even though autoscale is disabled (seen in LV2019 32-bit).
My expectation was only the waveform would be scaled in the Y axis, and not the axis limits too.
The simple workaround is to rewrite the upper and lower limits after writing the multiplier property, but I just wanted check that the observed behavior is by design and not a bug.
↧
C# send data to Labview
Hello,
I have a project to send the data from C# (Visual Studio 2013) to Labview 2018. VS2013 and Labview2018 are in one PC. The C# project only have to send the data continuously to Labview, so it is no need to receive data from Labview. The C# project includes product's SDK which has to be developed under c# console application, so maybe the solution of .dll is not suitable for the project (I'm not sure about it). Does anyone have any idea on dealing with this situation?
Thank you
↧
↧
SPI/I2C communication example with NI cDAQ and 9402 module
Hi,
I am having trouble getting started with NI Compact DAQ and 9402 module. I would like to run SPI and I2C communication, but cannot find any examples or even proof that it could be done. Have only found the drivers for cRIO, but not for cDAQ. Could it be that cDAQ does not support SPI and I2C? What a shame that would be. If you could put me on the right track that would be great.
↧
JKI VI Package Builder Bugs
Hello,
I would like to share with you with some weird behavior that VI Package Builder presents. I found 2 bugs (probably related to each other).
First Bug
VI Package Builder allows configuring package files destination. In Destinations pane you can see built-in destinations, which can be altered to suits your needs.
As you can see QuickDrop Plugins destination name cannot be altered because it is built-in.
I can add my own destination and then customize it as I like. However, when my custom destination name starts with the name of one of the built-in destinations, then the bug reveals.
In the custom destination, the name cannot be changed and it is now magically linked with the built-in destination. So if I change the subdirectory in my custom destination, the built-in will change as well. I'm afraid it is not a feature.
Check this behavior with The Tool - 1.vipb file.
PS: Use regular expressions with care 
Second Bug
VI Package Builder Test.lvproj contains files which mimic QuickDrop files (these are empty files, placeholders). The Tool - 2.vipb file should install this QuickDrop. Desired files location after installation should look like this:
C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\Tool.vi - Main QuickDrop VI
C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\_The Tool\Tool Support 1.vi - Support file
C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\_The Tool\Tool Support 2.vi - Support file
C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\_The Tool\Tool Support 3.vi - Support file
The configuration is as follows:
Package Source use MyCustomDestination (MCD) which is C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\_The Tool. Tool Support use parent folder destination which is MCD. Tool.vi destination is built-in QuickDrop Plugins destination which is C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins.
Installation effect is:
C:\Program Files (x86)\National Instruments\LabVIEW 2017\resource\dialog\QuickDrop\plugins\_The Tool\Tool.vi
Clearly not what I need and what VIPB configuration states.
↧
Variable Client Support 16.0
Hello,
What version of NI-cRIO do I need to install to get access to variable client support for labview rt 16.0?
I installed NI-cRIO 18.0 May 2018 and selected support for LV 2016 but then only version 15 was available and I could not install that on cRIO, when selected support for 2017 and 2018 then I got 17.0.0 which is too new (so I cant install that on my cRIO either).
Regards
↧
Opening Re-entrant sub VI front panel from main Vi front panel.
Hi all,
I'm relatively new to Labview (have been using it a while but not done anything particularly challenging yet!) so my approach may not be correct. I have created a VI that reads input from a data channel on a cRIO and then logs it to an excel sheet and I'm pleased that it is working as intended. This VI only logs a single channel however and for the final version of this program I will need to log 150 channels simultaneously and display the data on a front panel (data includes channel no., a plot, and a couple of Boolean indicators and is also where you input channel name and formulate the log file path). The other key requirement is that you must be able to stop, start, rename, and restart logging on each channel, essentially allowing you to hot-swap the input source to a new log file without affecting other channels.
Essentially I want to copy and paste my code 150 times with the front panel to create the program but obviously that isn't ideal as if I need to change the logging code then all channels will need changing manually. I have created the logging VI as a re-entrant subVI and copy pasted that and the program works as intended. The issue is that I have no way of opening the re-entrant VI front panels where the graphs and certain parameters are located during run time. I can open them by double clicking from the block diagram but that obviously wont be available / suitable during program run time. Using the invoke node I can make the subVI show / hide the front panel however this affects all clones of that subVI at once and not the specific clone I want to target.
First question: How can I display / hide the reentrant subVI front panel for a specific clone at will?
Second question: Is this an XY problem - is there a better way of doing this and am I making this more difficult for myself?
Unfortunately I cant share a VI here.
↧
↧
Reading data in multiple case statements
I am trying to decode parts of my serial data by using case statements in series. I can read data in the first case statement but not in the second.
The code works if I only use one case statement, so it appears I cant read any data in the second case statement.
I need to read the data at the indicators "FOOTER" and DATA_ARRAY".
Thanks
↧
Average every two neighbours through array
Dear All,
I have an 2D array and I would like to average every two values in each line.
For example an incoming array (sizeX=16,sizeY=8) will result into an outcoming array of 8x8.
I have implemented this already, but I was wondering whether you could suggest me a faster way of doing so?
In the Example below the incoming 2D array has a dimension of 768x1536 and the out coming 2D array has a dimension of 768x768.
Thanks a lot!
↧
Error at Configure Serial Port at Property Node(arg 17)
Dear all,
i try to connect with an old temperature measurement device. I use an USB-RS232 Apdater.
I was able to read out the temperatures with the Visa Test Panel from the NI Max, after i tried several different settings.
So i tried to copy the attributes from the NI Max and set them also in the Configure Serial Port.vi
In the end i have a problem with the Property Node(arg 17). This is the setting in the NI Max:
Here are the settings in the Labview.vi ; the numbers of the property node i hope are right?!Her
Here you can see the error in the Labview program.
I tried also the other possible settings at arg 17 but i always get this error code.
Can someone help me with that? Why there are this differences in VISA test panel and Labview?
Best regards
↧
Uninstall ONLY LabVIEW 2019
I recently had to uninstall/reinstall LV 2017, and apparently one of the toolkits I had installed the LV2019 demo.
Now, every time I start it, the activation wizard appears and wants me to activate 2019 and my LV2017 has a watermark saying it is a demo. I tried to uninstall LV2019, but the uninstaller says it's going to remove everything, including 2017. How do I remove 2019 and ONLY LV2019?
↧
↧
DAQ express
Hello,
I am using DAQ express. I want to record 4 inputs at the same time but cant find a way, is this possible?
I have 4 separate tasks created at the moment and can only run or record 1 at a time
Thanks
↧
Data communication
I want to transfer online data from 6 individual computers to single computer(server) through network switch using LabVIEW(N:1 Communication. Kindly let me know the solution for it.
Regards
Santosh
↧
Keysight N9020A (MXA)
Hello
I have started to work with LabView and by mistake changed in block diagram of examples block "CONFIGURE LEVEL (NORMAL).vi" . I cleared there few functions/blocks... and saved this file not like "SAVE AS".
Now this block is corrupted and I can not run any measurements of N9020B (MXA) where this VI block is used.
I am trying to recall examples, drivers from NI site but anyway this block is not fixed.
Could you please assist me and advise how I can fix this issue and restore "CONFIGURE LEVEL (NORMAL).vi" block
Thanks in Advance
↧