FPGA read write control node changing unrelated control when built and run as a startup rtexe

April 5, 2016, 12:26 pm

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I'm targeting a CRIO 9066. Running LabVIEW RT 2015SP1. My application works well when run from the development environment but when I build it and run it as a startup exe I noticed some odd behavior. I was able to trace it down to one node

That's writing 1 into the previous control (I8)

That is, samples should be 9 but if I execute the request node (FYI, it's a latching boolean, I don't know if that's relevant), samples becomes 1.

 

This only happens when run as an RT executable.  Any ideas or suggestions to prevent random errors like this?

 

Other details which may or may not be relevant:

Open FPGA reference opens the build spec (not a bitfile or VI)

Open FPGA ref is in a functional global that is used in multple places:

 

 

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Remote Development Application Error

April 5, 2016, 12:28 pm

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I am getting an NI LabVIEW Remote Development Application Error while running on a cRIO using LabVIEW FPGA software, see attachment.

 

What is the error?  Where is the Application Log?  I do not see anything in MyDocuments\LabVIEW Data\Remote Development directory.

 

Thanks,

 

Paul

 

NI-6009 USB - Stop Data Acquisition on one sensor but retain the last value it measured for calculations

April 5, 2016, 1:02 pm

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Hi everyone, I'm a beginner so I guess my question might be basic. So I'm working on a very simple project that should automatically record the mass of an object with a microload cell and also record the water displaced  with a liquid level sensor if the mass is placed into a circular container and is submerged.

 

Both the load cell and the liquid level sensor are working and give a change in voltage when the load cell is pressed or when the liquid level is touching water. And then I just need to calibrate the load cell so I scale the voltage into an actual weight or level measurement.

 

However, I want to calculate the density of the object as well which right now I have labview taking the current mass and level measurement and calculating the volume and then dividing mass over volume. But the object's weight and water displacement cannot be measured at the same time which is requried in order to calculate density.

 

The data acquistion is basically set at continuous measurements. I have one DAQ assistant that takes in the signal from the level sensor and the load cell and then I split the signal so that calculations can be done on them. Basically what I would like to do is to allow labview to stop data acquisition of the load cell upon pressing some sort of stop button in labview but it would retain the last value it stopped  at. This is necessary so it would still be able to calculate the density after I take the object and put it into the water container to measure the liquid level. Is there some sort of labview block that allows this to happen? 

 

Ignore the nested while loop in the top left, it doesn't do anything. 

 

Thank you in advance for any help.

 

Open VI Reference utilizando lvlib

April 5, 2016, 1:03 pm

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Olá,

 

estou tentando utilizar o "Open VI Reference" para chamar uma VI externa ao meu executável, o problema é que nessa VI eu utilizo algumas funções que fazem parte de lvlib do próprio LabVIEW como é o caso da função "Open Config Data.vi".

A minha VI externa funciona normalmente desde que eu utilize outras funções, mas quando tento utilizar esse tipo de função que pertence a alguma biblioteca ao rodar o executável a minha VI retorna quebrada dizendo que não conseguiu localizar a função "Open Config Data.vi" por exemplo.

 

Está é a VI que seria o meu executável, nesse caso apenas uma função para chamar a minha VI externa e abrir o Front Panel.

 

Está é a minha VI externa, utilizando apenas funções do LabVIEW, estas funções pertencem à NI_LVConfig.lvlib

 

Este é o erro que aparece quando abre a tela frontal da minha VI externa.

 

Tem algum modo de adicionar essa biblioteca junto com o executável para que a minha VI externa localize a mesma?

 

Obrigado,

João.

USB Set Configuration is always set to 0

April 5, 2016, 1:15 pm

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Hello,

 

I have a development board where I am developing firmware for a USBTMC device. This device will contain 2 configuration descriptors. In Labview, I issue a Control Out transfer to set the configuration to use per USB specification. Here is the code:

 

 

The bmRequestType's bit-map field corresponds to a Host-to-Device (0), Standard (00), Device (00000) request type. The request, 0x09, corresponds to SET_CONFIGURATION and value is the configuration descriptor number I wish to set.

 

When I run this code and observe on my ellisys USB analyzer, I see that the configuration value being set is 0 instead of 2. See below:

The highlighted area of the table shows what was actually sent over the bus to my device. This is problematic for 2 reasons. One, the code is not setting the desired configuration as expected. Two, instead of setting to the default configuration (1), VISA is setting the configuration to 0 which translates as "not configured".

 

I'm using LabVIEW 2014 64-bit with NI VISA 14.0.

 

Can anyone give any guidance on how I might be able to properly set the configuration of my USBTMC device using LabVIEW and NI VISA?

 

Thanks!

no output

April 5, 2016, 1:21 pm

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I am not getting any output. There are no errors when I run the vi file . I am trying to do serial communication with a machine to which we have to pass commands and which inturn has to return data, but even when I try any command I am neither getting any output nor byte count at port. The machine which i am trying to communicate has db9 connector, I am using db9 to usb converter cable and trying to communicate with the pc. I am using VISA for serial communication. I also did a loop back test by shorting pin 2 and pin 3 in db9 to usb cable in which i got the output for the given input. It would be very helpful if I get any advice .

error -2558 using Open data storage express vi.

April 5, 2016, 1:43 pm

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I have the appropriate Tektronix plugin installed and when I use the Open Data Storage Express vi to create new *.WFM file I get error -2558 indicating My system does not have the software installed to support the file type. I am using version 2015 SP1. Anyone else seeing this issue? What am I mising here?

SSL Certification and LabVIEW

April 5, 2016, 2:25 pm

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So I have just come upon an interesting issue which may cause significant problems unless I can find a reasonable solution.

 

Up until yesterday a number of software programs that are running in a number of remote locations were all running happily accessing a database.  This database is accessed through the HTTPS POST and HTTPCLIENT VIs, and for the past couple of years everything has been running nicely while having the verify server flag true, the database is part of a corporate site that is all properly signed and certified.

 

However, as of yesterday they all decided to stop, from investigating into the server itself it appears that the SSL certificate has rolled over from its previous period. By looking around the LAVA forums I managed to find reference to the problem being an the LabVIEW ca-bundle.crt file being outdated so not properly checking the validity of the new certificate.

 

Now while there is a workaround here that switching the verify server flag from TRUE to FALSE I can make all the programs work again, there remains the significant issue of having to update and rebuild several years worth of programs. So I was hoping for something that I could do outside of LabVIEW to try and resolve the problem, I had considered replacing the ca-bundle.crt but I am not sure of the validity of this idea.

So any ideas are likely to be accepted if they mean I don't have to go back over several versions of LabVIEW.

 

TLDR:

Can I do anything with this to solve the problem?

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Save for previous version from 2015 caused problems

April 5, 2016, 2:43 pm

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Hello all,

 

I did a CLD practice run using the Sprinkler System example. I built it in LabVIEW 2015, and then saved it for previous version to LabVIEW 2014 before posting in the Certification forum for comments. When it was opened by another member using 2014, the Read Delimited Spreadsheet.vi was not found. I can't duplicate the error because I don't have an install of 2014. The original thread is HERE. I have attached both my original 2015 project and the 2014 "Saved for Previous" version. Also attached is a screen shot from the attempt to open the 2014 version. Could this be an issue with the backsave?

 

Thanks to all.

Dan

Digital states - high impedance state detection in FPGA vi level

April 5, 2016, 2:48 pm

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Hello everyone, I have a question about how does the high impedance or high Z digital state look like in FPGA vi level. What I have is a PCIe 7852R multifunction card with digital IOs that are single-ended TTL.

 

If the digital input to the 7852R is HI or LO, I can detect the HI or LO in the vi. However, I wonder what I would see if the digital input is in high impedance mode? NI white paper says that "This state isn’t a high or low, but rather a floating or high-impedance state. It has the designation Z and is often used as an enable line." So what I would I actually see in the vi and how can I detect this?

 

Thanks for reading. I am looking for help.

 

Best,

 

A

controlling a 5v relay throught usb port

April 6, 2016, 6:05 am

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Dear All

 

 

I buy this 

 

http://www.ebay.com/itm/5V-USB-Relay-1-Channel-Programmable-Computer-Control-For-Smart-Home-New-/262337732951?hash=item3d148c2157:g:7acAAOSwoudW6ScT

 

And I thougt that it installs a driver to control it by COM port, but not. Seems that needs the create or write a dll library (I had never done that)

 

In attach is the data with dlls and a excutable to open and close the relay and it works, but I would like to put it working with labview.

 

Can someone help me?

 

 

Best regards

cpalha

where is IVI New Session VI

April 6, 2016, 6:31 am

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Running LabVIEW 8.5.1 on Windows 7 32-bit which is stated to be compatible by NI

 

I have a instrument driver VI for an optical spectrum analyzer which has in it the IVI New Session VI

I cannot find the IVI New Session VI in any pallette.

 

What am I missing?

 

This source code was rescued from a Windows XP PC hard drive which crashed.

 

 

 

 

Maths problem, converting change in voltage to change in displacement.

April 6, 2016, 8:18 am

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I get an input from an LVDT that ranges from roughly 0 - 5V. The arm travel on the LVDT is around 15.6cm or 156mm. So I've calculated that every time the arm moves 1mm the voltage changes by 0.03205128V. How do I go about the calculations to be able to show it on an indicator. I've tried to use a comparison to start with. So that every time the voltage equals let's say 4.7V, a case structure would increment an indicator by one. A problem here though is the voltage produced by the LVDT has too many decimals so that it never equals 4.7V. How can I change it so that it's limited to one or two decimals?  

 

Essentially what I want to show is that a change in voltage in the LVDT corresponds to a change in displacement of the arm. So a decrease in voltage means an increase in displacement and vice versa. 

 

I have attached my code to show what I'm trying to get at. 

 

 

Thanks for your help.

Using the build table Vi to build a table of a large array ( about 206 columns by 10500 rows

April 6, 2016, 9:08 am

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I am trying to use the "build table" VI to generate a table of large 2D array dbl (206 columns by 105000 rows). labview 64-bit but literally hangs. Thought moving from 32-bit to 64 would sort his out? Probes show that the 2D array is ready just waiting for the table to get built. Any work arounds?

How does the NI USRP-2920 satisfy Nyquist?

April 6, 2016, 9:20 am

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Acording to http://www.ni.com/white-paper/13881/en/, "The bandwidth and sampling rate are related as an I/Q rate of 200 kS/s has a bandwidth of approximately 200 kHz."

 

In all of the examples included for the NI USRP-2920, the I/Q rate on both the RX and TX match. From my understanding to satisfy Nyquist, the sampling frequency should be greater than 2 * [carrier frequency + 1/2(bandwidth)]. I'm still learning and may have missed something, but here are the questions I have:

 

1) How does specifiying only the I/Q rate allow sucessful RX and TX? In what senario would you want different I/Q rates fro the TX and RX?

2) What defines the sampling frequency? Does LabVIEW automaticly pick a sampling frequency based on the supplied carrier frequency and I/Q rate?''

 

Any input would be greatly appreciated, thanks for reading

-Pat

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How to select a record from a table to manipulate the data in a database?

April 6, 2016, 9:30 am

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Hello Community,

 

Using 32-bit Labview 2015.

 

I created a user interface that runs a query and fetches my table from a sql database.

I want to be able to manage one record at a time by selecting the record from my table and then manipulating the data as needed.

 

Everytime the user runs a query I want the first record in the table to be selected/highlighted.

I want an indicator showing which record is currently active.

Then by a button click, to be able to scroll through the actively selected record.

Once I have the selected record, I want a way to write a query to edit or delete the record.

 

Attached is a picture of my query to select all from my table and plugging the data into my table(results).

Attached is a picture of my table showing the records from my sql database.

 

What is the best way to go about selecting a record from a table and editing the data with a query?

 

Any help would be greatly appreciated.

 

Thank you 

linear discriminant analysis

April 6, 2016, 9:41 am

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Hello everyone!

I am new in Labview. I would like to implement a linear discriminant analysis.I wanted to know if anyone can pass me an example of any kind that makes me understand how to get started. Thanks so much.

Francesca 

create attribute NS

April 6, 2016, 9:49 am

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How do I add namespace to an xml? I used "Create Attribute NS", but it does not show in the xml. Thanks Tony

Bronkhorst F201c mass flow controller using LabJack U3

April 6, 2016, 10:51 am

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I want to create a Lab View program to control a bronkhorst mass flow controller. The communication is with Labjack U3. I need help creating the program. Can anyone please help??

How to measure digital output of linear actuator on USB 6009?

April 6, 2016, 11:14 am

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Hi,

 

I am a new Labview user and need help with measuring a digital input signal.

 

I have a Bimba Original Line Electric actuator with an integrated DC motor with encoder, drive, and controller. The drive has a programmable digital output which I have set as a tachometer output that emits 100 square wave pulses per revolution of the motor. I have set the motor to make a total of 56 rev over 22 sec. I want to measure the real-time motor rpm on labview and synchronize it with a few other analog input signals. I wired the actuator to the USB-6009 as shown below.

 

 

I opened the USB-6009 Digital I/O test panel and set all the port 0 lines as inputs. However, when I click start and run the actuator, the p0.0 led doesn't blink, as shown below.

 

 

Shouldn't the led blink in response to the motor revolutions?

 

I essentially want to collect the pulse signals from the drive and convert them to rpm on labview.