We have to transmit an image through laser source and receive with the help of photodiode. How to receive image in following program? suggest changes.
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image reception
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Gamma function in LabVIEW
Why does gamma(0) in LabVIEW give me (NaN)?
While in Matlab, it gives me (Inf).
I don't thing (NaN) is ever generated by a gamma function, it should be (Inf).
This is very significant when I would like to do division, as any number divided by (Inf) gives me zero.
As whith NaN, any operation with NaN gives me another NaN.
Please let me know, if I am wrong, or this is a bug in LabVIEW.
Thank you in advance.
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[FPGA] Reinterpret FXP
Is there a way to reinterpret a FXP number with a control? So that I can choose the number of positions I want the decimal point to move without increasing the number of bits used, nor losing precision.
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Casting a DVR to more specific within an IPE
So I have following use case: I have a UI and a state machine which I want to be able to share the same object DVRs. This is to easily allow me to alter the parameters of the state machine object while the state machine is running.
I also want to have a modular UI so I have a UI for each object running asynchronously in a sub-panel. So far so good, all works.
Now I wanted to actually store DVRs instead of objects themselves and I ran into an interesting behaviour.
If I define a parent static method with a DVR input which contains an IPE which then calls a Dynamic dispatch version of the "Launch UI" while branching the DVR before the IPE and inputting it as a parameter to the "Launch UI" (so that they will share the same DVR but still allow Dynamic dispatch) then I am forbidden to even perform a "Cast to more specific" within the "Launch UI" VI. I have to pack it into the init portion of the actual asynchronous UI.
The VI shown here (purple banner) launches an async VI which accepts a DVR as a parameter. I wanted to pass a strict DVR (the purple VI is dynamic dispatch) but this has caused problems. In this image, if I try to perform a "Cast to more speficic" in the VI shown with the purple banner, I have a deadlock. If I pass it as a base class but do the cast in a VI started asynchronously, the IPE will exit and the cast can continue.
Is this expected? Is the IPE preventing me from accessing the required information from within the DVR needed to do a cast? I can't do the cast outside of the DVR because only within the DVR (in the Dynamic dispatch VI) do I know what I want to cast it to.
It surprised me a little, thus the question.
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Case structure with combined input values for the selector?
Hello,
is it possible to implement a case structure with cases that come from two different sources (for example enums)?
The application would be a state machine that has states that are triggered from outside (like start, pause/resume, stop) and other states that are triggered from inside the state machine.
I want to separate those inputs in terms of external and internal inputs.
I could, of course, put all cases (regardless if they are triggered internally or externally) into one enum, but that doesn't seem like a clean solution to me.
Please find attached an example.
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Data between peaks
Hey guys,
I would like to get the average value of the signal between (yellow region in the figure) two peaks (or valleys) and export it to a text file. I have a program for finding peaks and valleys but this is bit complicated.
Any help would be much appreciated.
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multiple instance executable needs re-entrant VIs ?
Hello,
i'd want to launch multiple instances of a LabVIEW built executable. I found that it can be simply done just by adding the right line in the .ini file. Ok.
But i wonder what's the behavior of the sub VIs, mostly those which retains some state data in shift registers : do i need to make them re-entrant, or does the multiple instances option automatically duplicate all subVis ?
Thanks for any information,
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How to get voltage from sensor analog input on labview
Hi, i am newbie here, i am doing my minor thesis about how to detect CO, Methane, and dust particle (PM10) with MyRio and labview. for sensor I am using mq 7 for detect CO, mq 4 for detect methane and sharp dust sensor g2yp1010 for dust particle. I am confused about how to get voltage from those sensors in labview. I already used AC DC estimator PtByPt.vi but the value that I get is small value that smaller than 1.221 volt that minimum voltage if using 5 volt as supply. For example, in datasheet Sharp dust sensor, to get right dust density we using divide between voltage and dust density (open image file). in the graphic we know the smallest voltage is 0.9 to get smallest density. but in my code i get value 0.01 till 0.09 (using AC DC estimator PtByPt.vi). please teach me, I dont know what to do about this.
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Delete TDMS Group bug
I have found some strange behaviour in LabVIEW 2015 SP1 regarding TDMS files. I discovered that a group in a TDMS file that has properties but no channels cannot be deleted when it is the last group in the file.
In order to demonstrate, find the attached demonstration VI.
When I first delete the group without data (A) and then the group with data (B), everything is fine.
When reversed, thus the last group in the TDMS file has no data / channels, it cannot be deleted.
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Array manipulation
This is a little difficult to explain but here I go. I want divide an array as measurements are taken and split the data up into columns at certain trigger points. I have an array of boolean buttons to trigger the saves. I only want the data above these points to go into the chosen column. This VI is what I'm currently trying to get to work. I'm sure I'm going about it the wrong way. Help!
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Problème affichage graph 3D
Bonjour à tous,
J'ai un soucis avec les graphs de contour 3D. Dans un lecteur de rapport, j'affiche les représentation 3D de plusieurs données dans différents onglets. Sur mon PC de développement je n'ai aucun soucis, j'obtiens une belle image pour tous les graphs et les quatre mode de projection en bas à droite marche tous très bien :
Cependant, une fois que j'ai construit l'application et l'installeur et installer le tous sur un autre PC ( tout aussi performant que mon PC de développement), certains graph vont bien comme précédemment, mais d'autres ont une différence de texture que je n'arrive pas à enlever :
Sur mon PC de développement j'avais vu cela lors des premier tests et corriger la chose en désactivant l'éclairage dans la partie lumière des propriétés du tracé 3D ( je tiens à signaler que tous les graphs sont du type contour 3D avec les même propriétés et traitent le même type de données).
De plus, j'ai également un soucis au niveau des modes de projection. Quand je veux changer, le cadre change, mais pas le graph :
Il faut que je clique sur le graph pour qu'il s'actualise et prenne la bonne disposition :
Mais je pense que les deux soucis sont liés puisque je n'ai pas le soucis des modes de projections sur les "bon" graph.
Quelqu'un saurait-il de quoi proviennent ces soucis et comment les corriger ?
En vous remerciant,
Cordialement,
Nathan
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String to number conversion
Hi guys, I am new on labview and I need your help. I need to convert a string in a number, but I am acquiring data continuously and when I do the conversion I only obtain the first number of that string. Instead I have to acquire all the numbers, or better only the last or the last five, in such a way I could do an average (also I don't know how to do it) between these ones and obtain the value to put in pid control.
This because I am acquiring the value of the thermocouple, and when I run the program in the string I visualize continuously the value, but for the number I visualize only the first value, and it doesn't change anymore.
How can I do it? Thanks, Vincenzo
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Agilent ENA Driver - Custom SCPI Commands
Hi all,
I'm currently trying to perform several functions which there doesn't seem to be a 'VI' for within the Labview Agilent ENA drivers. One of these functions is to disable the warning beeper, however the Agilent ENA manual shows an SCPI command of:
YST:BEEP:WARNTAT
Which enables / disables the warning beeper.
Is there a way I am able to send a custom SCPI command to my Agilent ENA (E5071B)?
Many thanks,
Charlie
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Symantec antivirus causing high CPU usage
Looking for recommendations regarding adding exclusions to Symantec 14 to prevent high CPU usage from antivirus scanning when using LabVIEW development on a windows 2016 server environment.
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database: read NULL values from timestamp
hello
the VI below returns an error when the database field "packaging timestamp" is NULL.
the database field is written like "2017-02-16 11:09:20.000"
and the labview timestamp constant has the properties below (sorry about french):
can you help?
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measurement and automation database connection error
Hello,
I'm wondering if anyone has had this problem. I was running a Labview program one evening and everything was fine. I shut down the computer when I left, and the next morning when I booted up, the labview on my computer isn't communicating with the DAQ chassis.
When I open up MAX, I am getting the database connection error described here. http://digital.ni.com/public.nsf/allkb/B9107A7F281F9B408625720B0078E5A8 I appear to have the problem described in #2, where the NI Configuration Manager starts but immediately stops. However, repairing the program didn't fix it, and my firewall settings haven't changed. Has anyone had and solved this problem?
FYI, I'm running labview 8.2 on a very old testing computer without internet access and updates.
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The best way to wire a Microphone on NI 6120 DAQ card and acquire data
Hi Folks,
I would like to wire a Microphone in my DAQ card NI 6120 in order to acquire audio better then the USB audio adaptor because I need to have a very high data resolution to test what is bad and Good in my products. Anyone have the best practice or good ideas to do this and would like to share ?
Thanks in advanced,
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Phase Locked Loop (PLL) at 80kHz using sound card input and output signal
Hello
I'm building an induction heater hoven that consists on a simple RLC circuit and a switching circuit that should be run with the resonance frequency (fR) of the RLC circuit. As the fR changes with the temperature increase, I need to implement a PLL that compares the signal (Vin) phase and the current (C) phase to keep them in phase and achieve fR along the heating process.
I made the Sound OUT.vi attached to use the sound card as signal output for a square wave but signal that I read in the oscilloscope is nothing compared from what I need.
Can someone assist me in this problem?
Best regards
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NI-845X I2C communication example
Wondering if anyone would be able to give a sample on how a read/write message is built up for this type of I2C communicaiton.
Im trying to use the NI USB-8451 I2C host adaptor to talk to a LTC4306 multiplexer. I will be talking to other devices ( temp sensors, SE98ATP) through the multiplexer, but thought I would start with trying to talk with the first device in the path (the MUX).
Looking at the data sheet I think I may need to use the I2C scripting commands to build my read and write packages? What I really dont get is how to build up the message. My slave address is (1000 000) [7 bits] so Read/Write is 0x80 / 0x81 respectively. "Register"[8bits] and "DataByte"[8bits] would be my inputs in both the read and write cases and I would choose them based on the data sheet and what operation I need to perform. But how to build up an I2C message as I show in the picture below completely eludes me..
For refrence
- Data sheet = http://pdf1.alldatasheet.com/datasheet-pdf/view/265255/LINER/LTC4306.html
- I'm using LV2015
Protocol (see pic below)
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TCP/IP VIs can really run in parallel ?
Hi all !
I'm using the STM library (over TCP) to communicate between a client and a server (which are 2 cRIOs). 2 ports are opened (55000 and 56000) because I need to send 2 kind of messages.
On the first port small messages are sent often (82 bytes every 2ms). On the other port much larger data is sent but less often (160k bytes every 50ms).
The reader is reading each port in a separate loop. The timeout of the STM read is the only thing which rules the loop timing. So each loop should run as fast as they received the data (so approximately 500Hz for the first port, 20Hz for the second).
I noticed that every 50ms, the first loop takes almost 6 to 10ms instead of the usual 2ms. So it is quite clear that the second loop as an influence on the first one...
STM VIs are all reentrant... Is it the TCP/IP library which is no reentrant or the bottleneck is much deeper (in the TCP stack ?) ?
Is there any way that I can have my two loops running independently ?
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