Labview option in selecting hardware

August 31, 2016, 10:14 pm

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I have selected some NI PCI, PCI EXPRESS AND USB CARDS...while selecting PCI
cards the option of labview software appears and not in the case for PCI
express and USB.. My question is that in PCI express and USB does the software
is a part of card.. Pl elaborate because I'm purchasing it first time...also
LabVIEW is available easily on internet as a free software so why is ther need
to purcphase it? I have selected labview with all features while selecting
because I want to explore it completely.. Thanks

regards

Adeel

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labview arduino uno bad transfer of data

September 1, 2016, 12:23 am

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Hello,

 

i have some problems with transfer of data from the arduino uno to labview.

I have made a VI where i can control the power of a heating device with temperature measurements with arduino uno.

 

The problem is that once in a while the wrong temperature is captured in labview by missing the digit or a number eg. labview gets 2000°C in stead of 20.00°C or 1.25 °C in stead of 15.25°C.

When i watch the serial plotter from the arduino program these mistakes do not occur. So I assume it will be a problem with labview settings or my VI.

 

In attachments a set of data extracted from the VI and the VI itself and the arduino script

Triggering digital input in PXIe 6363

September 1, 2016, 12:24 am

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Hello,
I was using the Daqmx to generate digital signals. I have a VI which writes digital signals and reads the digital input back continuously. I want to read a finite number of samples. For that I had the start task, read and stop task inside the same while loop. This works fine but then the VI is slow. So I wanted to trigger the digital input and take the start and stop task outside the while loop so that the VI runs and reads the digital data till the stop command is received. This does not work for some reason. I am posting my VI with this post. Can anybody please help me where I am going wrong.

Which CAN card should i buy?

September 1, 2016, 12:36 am

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Hello,

i want to create an application where the computer is the Master and is connected to 10 devices as slave.

Currently i have no CAN card.

 

As far as i read the new boards are programmed using the NI-XNET API.

1. Is this software included with the card or is it a separate purchase?

2. Does it contain "read-to-use" labview-vis?

3. Is it correct that if i use/install the NI-XNET API then i dont have to care about NI-CAN, CanOpen, OpenCan, ....?

4. And the most important question is: Which card should i buy?

 

Thx for help

make waveform from multiple timestamps and data-Y value

September 1, 2016, 12:40 am

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I have  multiple timestamps at which instance I have data  (say a  1 or 0). I want to make a single  waveform out of these variable timestamps and the data associated with it.

 

background: I read Bus- Frame information and generate the timestamp based on the difference between 2 bus Frames.

 

Issue -  the  dt value cannot be  same as sometimes the frame data can come at a difference of 10 ms or 30ms. Hence Timestamp for each data.

How do I get a waveform out of this data.

 

Problem Whit Solution

September 1, 2016, 12:55 am

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Hello, I developed this software to create a test You can choose two types of operation , complete or NO test. The part of the complete test is working properly , check all the entrances to the outputs and prints a file the report ... The problem is that I do not know how to do instead the part where it stops when it finds an error , after the error message , the operator must press OK and double-check the same program , will not advance until the control is not ok . I don't understend, The FOR is AutoIndex whit Array and I find the error Number (4,9,14) but I wuold repeat the test to error 4

Sending the program , the test file ( TestFile.txt ) and the report file ( Report.txt )

 

 

 

MyDAQ logic analyser

September 1, 2016, 1:08 am

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At my university students use a NI MyDAQ to do measurements.

We use the NI ELVISmx instruments for almost everything except XY-plots.

 

I have a project that could really use a logic analyser, and the MyDAQ has 8 binary inputs, but the Digital Reader instrument is pretty useless for this application. So I opened LabVIEW and created attached vi.

 

However, the problem is the speed and timing. This for loop runs as fast as possible, which seems to be 50-100Hz. Now of course I did not expect megaherz performance from this device, but since the oscilloscope goes up to 20KHz, I was wondering if there is a way to make it faster and more controlled. (I found there are timed loops, but no clue how they work) Maybe I need to used a more low-level interface to the inputs?

 

Generating microsecond pulses

September 1, 2016, 1:46 am

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Hello,

 

I am new to LabView and want to generate specific output signals. Everything >1ms works fine but is it also possible to generating pulses, with a pulse width of for example 500µs?

 

I am using the NI cDAQ-9178 with a "NI9474 DO24V Source High Speed" module.

 

Thank you

 

Best regards,

Chris

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Variables in the ode solver function for MathScript

September 1, 2016, 2:17 am

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Hi

 

I am using LabView for a long time now and I started to use the more text based tools. To solve a system of differential equations there is this quite elegant tool to do this in a MathScript Node with the ode solve algorithms (for example "ode_adams"). As the LabView help says, I defined a function and saved it as a .m file. I loaded this function in mathscript and it solve the differential equations.

 

So far so good, but my problem is that I can't get any variables into the function. I can only put numbers in the function but no variables. Unfortunatly I need to define the variables outside the function in the MathScript node.

 

Does anyone have an idea how to handle the variables in this case?

I attatched a picture of the function and the test VI (LV2014).

 

Greetings

plotting two arrays on the same chart

September 1, 2016, 4:15 am

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Hi, 

 

I have some data which I would like to plot on a chart but I would also like to plot the middle section of the data in a different colour. Imagine a bell curve where the middle peak is to be a different colour so the outlier sections.

What i have done so far is to get the two regions into different arrays, now I need to combine them into the same array to plot together. However I don't know how I sync them. At the moment when I plot them the middle section is plotted from index 0 on the x axis when it needs to be shifted by an offset. I have thought about placing it into the correct index however this will result in the ends being plotted as zeroes which is unwanted. 

 

Thanks 

Stephen

Using I2C waveform in DAQ-mx

September 1, 2016, 4:17 am

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Hi all,

I am working on I2C protocol and would like to test it using DAQ-mx on a PXI. I have created the digital I2C waveform. But I am confused on how to use it with DAQ-mx, like how to input the signal and how to get the output. I2C communication has two lines-SCL and SDA. Should it be given separately by creating two different tasks or can be given in a single task? Also, how can I read the acknowledgement from the Slave based on which further transmissions are dependent(i.e.) How to configure it to read acknowledgement at the HIgh-Z state? Can anyone please help me out?

Thanks for the help in advance.

Use of DVR inside class

September 1, 2016, 5:08 am

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I'm not able to solve DVRs problem. See project file.

1. IO.lvlib exists in two versions: one with single variables + processSimulation.vi that simulates process/machine i.e. takes outputs, calculates process behaviour and writes inputs; the second version of IO.lvlib has variables as IOaliases. Simply swaping these two versions allows to run project on real target with machine or to run project on PC without target/machine. Thats why I use these IO.lvlib variables.

2. Every subsystem is an object/class with method DoSomething that calculates response to inputs and writes outputs.

3. I¨d like to call these objects DoSomething.vi method in one loop. Thats why it's not possible to have inputs/outputs as terminals of DoSomething.vi

4. I've tried to solve the problem with DVRs: every object is created by constructor including inputs/outputs DVRs initializing. However I'm not able to use DVRs inside DOSomething method. What am I doing wrong?

One solution is to avoid loop call and spread all (about 50) DoSomething.vi calls including inputs/outputs terminals onto block diagram. But this is definitely not well arranged solution.

Do you see anything wrong concerning my solution in general? How to access DVR inside class method? Any other ideas, comments? Thanks.

End of file encountered error for reading multiple columns from a TDMS file

September 1, 2016, 5:21 am

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Hello LabVIEW fans,

 

I am writing data into multiple columns of a TDMS file. After this I would like to read the data from each column to process it.

 

writing the data works without any problems, so I get a TDMS file with lets say 4 columns of data. When I try to read these columns now, LabVIEW always gives me Error 4 "end of file encountered" for all but one tdms read functions. It doesnt matter how many columns I read or how big they are, its always the same. LabVIEW reads one column and gives the error for all the other tdms read functions.

 

Does anybody has an idea how to solve this issue?

 

Attached is a picture of my VI and the error.

LV 2016: LabVIEW could not create the requested channel endpoint File permission error; NI-488: DMA hardware error detected

September 1, 2016, 5:41 am

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I've just installed the new LabVIEW 2016 with both patches, and wanted to check the new functionality.

When creating channel writer, there was a pop up Select Channel Endpoint, but regardless of selected option, there is a window saying "LabVIEW could not create the requested channel endpoint", error ccode: 8 file permission error

NI-488: DMA hardware error detected.

 

I have file permition error for some file, which file is it?

Open vi reference

September 1, 2016, 5:55 am

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Hello,

can anybody tell me why LabVIEW doesn't finish execute of the "open vi reference" function when I'm interacting with e.g. context menu? I have attached a picture for more understanding.

 

 

Regards,

Thomas

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Queues are not working in my object oriented design

September 1, 2016, 10:15 am

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I am developing a real-time application, and am utilizing an object oriented approach. The design pattern is similar to the Actor framework, but custom built. The class structure is setup to support several different subsystems, with the highest class being a "subsystem" class. Currently, I have only one motion sub-class just to verify inheritance, but my problem is with the subsystem class.

 

Each subsystem object has a few parameters, one of them being an "Execution Queue". It is a queue of 1D string arrays which tell the subsystem what to do on the next trigger. Each subsystem is launched in a manner similar to the actor framework (I used "Launch Actor Core.vi" as a guide, so this means using an Asynchronous Call By Reference (ACBR). I simplified it for my purposes and also closed out the reference which the actor vi does not do (I had problems even when was leaving the reference open), see below image.

 

The "SETUP" VI you see in the image is where the queue is initialized, I won't include that code as it's pretty straightforward. I have verified that the queue is created properly. None of my downstream code from the launch modifies the queue, it only accesses the queue. When I try to perform any operations on the queue after the launch VI, I receive the following: "Get Queue Status in Subsystem.lvclass:Message Handler.vi:640018->Subsystem.lvclass:Controller.vi:4750017->Subsystem.lvclass:Controller.vi.ACBRProxyCaller.A84000DB".

 

I receive similar messages for any queue operations I attempt to perform. I have also verified that - for the operations where I receive an error - I have the same reference that was created during setup where my queue operations performed successfully. The only difference between the setup VI's and my problem VI's is that the problem VI's are within the VI that I call through the ACBR.

 

Any help you could provide to me as to what I'm doing wrong or if I'm attempting to do something that can't be done would be greatly appreciated!

 

Thanks,

Ben

 

 

Sofware based GLONASS receiver using labview

September 1, 2016, 10:46 am

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I am designing a software based GLONASS receiver using LABVIEW.I have obtained doppler removed I and Q signals separated from the received signal S(t).Now,how do I proceed further in data acquisition.

P.S: I want to use FFT method for data acquisition.

cleanup just stopped working

September 1, 2016, 12:29 pm

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I was using LabVIEW to edit some block diagram and hit ctrl-U and nothing happened.  I did it 5 minutes ago and it worked. 

So I moved something out of place and tried again.  Nope.

 

What the what??

 

So I got the idea that Microsoft was (once again) out to make me grumpy.  I restarted the computer and there was a new update.  It was 105 ... 25% ... 90% ... done.  Restarted.   Yay.  That might have it.

 

Nope.

 

Control-U is now no longer working.

I didn't change any setting anywhere.

 

Here is computer info (names were changed to protect the innocent).

Here is version information for LabVIEW (names again changed to protect the innocent)

 

What gives? 

How do I make this work again?

Integrate Start Asynchronous Call with Static VI Reference

September 1, 2016, 12:56 pm

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A while ago, I posted this idea.

http://forums.ni.com/t5/LabVIEW-Idea-Exchange/Integrate-Start-Asynchronous-Call-with-Static-VI-Reference/idi-p/3307187 

It turns out there is a solution.

Call by reference nodes have a (private) "Configure" method that puts a static VI path into the node.For example:

The attached VI is a tool to let you setup a Call By Reference node.

1. Run the VI.

2. Single-click on a Call By Reference node.

3. Browse to the desired VI.

4. Click on Apply.

Build Application Error 7

September 1, 2016, 1:24 pm

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Hey everyone,

 

I had a computer issue and IT had to reinstall some hardware on my PC - now when I try to build the application it comes up with error 7, no matter where I put it. It seems like it isn't creating the file at the destination. Any thoughts at how to fix this?

 

Thank you,

 

Anthony