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Problems in Keithley 4200-SCS Labview Driver

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I am using labview drivers for Keithley 4200-SCS, downloaded from Tektronix official website: https://www.tek.com/software/4200-scs-labview-lv-version-7-driver-beta-release-25mb

 

I take a test by measuring the I-V curve of a resistor on a probe station using KITE in 4200-SCS or using Labview program KI4200.vi. Parameters in two cases are all the same but the results don't agree with each other. And I find even when there is no device on the probe station, test using  Labview still gives the same result as there is a resistor. So I guess there must be something wrong with the drivers.

 

Attached are the curves I get. Thank you in advance for your answer.

 


Adding noise and channel to ofdm signal

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Hello,

I have created an ofdm VI (Transmitter and receiver). Now I want to add a noise and to apply it to a random channel. Please help me to do this. The output of the ofdm is 1D array of double complex.So whenever I try to add noise to this the wires becomes broken. 

Gap between DAQmx and computer clock

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Hello,


For quite some time I have been experiencing a gap between the PC time and the time returned by the DAQmx waveforms.
I designed a test software with a simple principle, which is responsible for performing test sequences.
At each test step, the software positions the outputs of the test means (DAQmx of laboratory devices).
Continually during all the operation (which can last up to a week), I acquire the inputs of the test means, generally at a frequency of 3kH or 20kHz, continuously, to lose no value.
The problem is that it creates a gap between the time given to me by the PC and the time returned by the waveform DAQmx, which generates me errors!

To illustrate and verify this phenomenon I made a VI that compares the time from the DAQmx waveform and PC time :

Acquisition continue_Programme de capture.png

 

We see that there may be a gap of more than one second over 24 hours of execution :Acquisition continue_Capture.PNG

 
How to remedy this problem?

Thank you for your help.
Cyril

 

Labview merge two charts from different while loops

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Hi LabVIEW enthusiasts Smiley Happy

 

I'm trying to merge two charts from different while-loops. I have simulatenous two while-loops that do these things :

1) First while-loop is used to generate sound and display it as chart.

2) Second while-loop is used as serial communication that displays voltage from soundcard (generated by 1st while-loop). The voltage is acquired by ARDUINO UNO and send the ADC value through serial communication to labVIEW to display as a chart.

parallel.PNG

 

The problem is I can't merge those charts into one chart. I have tried with making a bigger while-loop that contains those two loops, trying move the 2nd loop into 1st loop, still failed. 
So do you guys have any idea to do this? Thank you very much for the help or hints. 

Calling a vi from exe

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I am developing a project in which I need to call a particular VI from calling VI. I have done it in development. Next, I have created an application for a calling VI. It calls a required VI from where I have saved it and works fine. My doubt is Do I need to keep that called vi as a vi even if I distribute an application to my customer? Hope I have told my doubt correctly.

Recommended Antivirus Exclusions

Device name in NI MAX getting erased or reset

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Hi all, 

I have a Profibus module in my PXI system and I'm calling it's reference with the name PROFIBUS, at some instance the name entered in the NI MAX card details getting erased and affecting my communication? Is there any reason for this behavior?

Timer timing.

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Hello all,

I am new to Lab VIEW, but I have a sequence structure vi project, where in between the sequence I have a timer of 20 seconds wait. How can I make that time while is timing from 0 to 20 seconds do display in front panel ?


Probe watch window is not working

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 I am using 2015 Labview software. I cannot able to view probe watch window. I can place probe on any wire but once I double click on the probe I cannot able to access probe watch window instead probe on corresponding wire is getting selected.

In task manager, I can find probe window, but I cannot able to locate. All other debugging tools are working fine.

I have checked VI properties->execution->allow debugging(is enabled).

What may be the cause? But earlier time probe window is working fine. Currently this problem arises.

DSC SV Security settings overruled by accessing them from different subnet

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Hi there.

 

Apparently I can have access to a SV using data binding as long as I come from a different subnet.

In the Print screen you can see the SV TTR5 is deny for the PC 9697 and PC 12174. However PC9697 (same subnet like host) has no access while PC 12174 (different subnet) has.

Only Deny all host * seems to help but I don't think that how it's supposed to be.

 

I'm looking forward to hear some advice or conclousions about that.

 

Regards P.

 

Compare Digital Waveform to Binary String Array

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Hello,

 

My question is fairly specific, so hopefully you can point me in the right direction either on the forums or in a response.

 

I'm attempting to build an array of binary code saved in string constants and compare it to a digital signal that I'm continuously PSK demodulating from a radio transceiver. I'm eventually going to flag when any of the strings in the array match the incoming bit sequence to ~80% accuracy.

 

I haven't completely jumped into the task above, since I have quite a few binary strings to add and I just want to get a grasp on how to do the comparison before I start. Thus attached is just a flow diagram of my process.

 

Any snippet on how to start this would be appreciated.

What is Difference between CLAD ( LabView 2017 ) & CLAD ( Nxg)...?????

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Hi Friends,

What is Difference between CLAD ( LabView 2017 ) & CLAD ( Nxg) ?????

Tracking down memory leak

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Hello, so I am working on a VI at work that somebody else created.  The code is a fairly simple DAQ program that stores data locally and remotely.  About half of the times that I run the program, it runs for a little while and then crashes with a message that says "not enough memory to perform this operation."  I checked Windows Task Manager and the memory used by the VI quickly grows by about 800KB per second until it reaches about 2.4GB and then crashes.  I checked the size of every array and that is not what the issue is and I used LabVIEW's Profile and Performance and Memory manager and took a snapshot of all the VIs.  I don't use this tool often so I'm not sure if there are any clues there but I would welcome some help.  I cannot share the code because it is proprietary but they put a stacked sequence inside of a while loop that continuously takes samples of data and stores it.  It is running on Windows 7 and using LabVIEW 2014.  It is important to note that this does not happen every time.  Sometimes the memory usage is constant and there is no issue.  Thanks for the help.  

Changement de fréquence d'acquisition de données en externe

PID for temperature control

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Hello,

I have been trying to control the temperature through labview in stead of using a PID controller (Omega CN740). I have been collecting my temperature data from C-DAQ NI-9211. So, its dynamic data. I have been using this data as the input of my process variable.  Therefore when i start running the PID VI, the vi is supposed to continuously compare my process variable and set point using the PID gains given. And it should give me an output. I am converting the output to percentage and then simulating a PWM signal. And based on that signal, i get on/off condition to relay. and that runs my heater to heat the element. 

Whenever , i am trying to run the code, initially its overshooting a lot and then keep fluctuating. Therefore, i am never finding any steady temp. I have tried to run the autotuning option too. As the signal is never becoming stable, the auto-tuning process is not returning any PID gain out. 

I, exactly dont know what's the problem(whether the code or my trial n error PID gains input). I am attaching my VI here. It would be great if someone can give me some feedback about solving the issue. 

Thanks,

Arnab


Measuring time delay between Arduino Uno and Labview

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Hello,

 

I am very new to the community so please forgive me if my question is trivial. 

 

I am a University researcher and I have been given the task to measure the time delay between labview and an Arduino Uno. The problem is that we are controlling an Arduino Uno board with labiew and want to measure the time delay that it takes for the input information via labview to be carried out on the Arudino Uno. I have an oscilloscope in my possession as well but am still not sure how I should go about testing this. If any of you have an idea of a good place to start measuring this time delay please let me know.  

 

Regards,

Optics22

how to control SS/ chip select line .. in SPI using HSDIO

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Is there any chance of making chip select (High) de-assert at middle bit of particular transactions without modifying the behavior of other signals (sclk, mosi, miso) in SPI Communication using HSDIO.

Change the speed of an audio file real time!

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I am reading an audio file using Sound Vi in labview, i need to change the sampling frequency/ speed of the audio file. Can someone please guide!

 

Much appreciated!

Tracking mechanism - while loop with voltage subtraction with shift registers

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Hi there,

I hope somebody will be able to help me with a simple (at least I was thinking like this) code… I need to implement the algorithm in Labview has been designed in Matlab/Simulink. The trickiest part for me was implementation of Memory blocks (initial value=350 and initial value=0) that will be able to save values for the previous iterations.

 

function u2=fcn(speed,u2d)

if speed>120

    u2=u2d+0.25;

else

    u2=u2d;

end

 1.png

AI measures an electro-hydraulic drive speed. AO generates a control signal that will power up the drive-train. When the speed exceeds a threshold (120 in our case) the code should decrease the control voltage in order to decelerate the drive and stay below the threshold without any further changes (hence the control system should keep the latest “successful” voltage). The model above runs the drive at 350 rpm from its start.

 

In the algorithm I am doing the comparison speed>120 and sending its Boolean output to a switch with two inputs (0 – false) and u2d – true. The reason I’ve designed to use 0 is because I don’t want any changes to the control voltage before the algorithm kicks in.   The code u2 = u2d + 0.05 is built on shift registers. And then u2/u2d I am subtracting from the control voltage to decrease it to the required level below 120 threshold.

 

The point is that after the comparison speed > 120 becomes “false”, I want to keep the value of the voltage (u2=u2d). But since I am using a switch in the top part, when it gives falls, it sends zero + 0.05 to the node AO0 and then the cycle starts again (these voltage spikes gives speed spikes). I was trying to use different combinations of switches and also case structures, but any results. I know that I miss something simple but could not figure what exactly. Will be great if somebody can help out with this case. Thank you in advance.

Mismatch array elements

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Hi,
I'm comparing the two input arrays, I'm in need to determine the mismatch elements between two arrays.
I've attached the image for the reference.

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