• RELEVANCY SCORE 3.22

    DB:3.22:Time Based Peak Matching Vi 99






    (Using LabVIEW 2012)

    Hi all,

    I'm still fairly new to LV (and you will probably see evidence shortly), but I've been working on developing a VI for data acquisition of a gaussian shaped multiple channel PMT signal (voltage), where two separate signals appear with different amplitudes separated by a roughly constant time delay (with some tolerance), henceforth known as Spot 1 and Spot 2. I'd like to match these peaks given a time window.

    I've attached my attempt so far, but the way it functions, the while loop operates everytime there is new data from either Spot 1 or Spot 2. I only want it to operate when there is new Spot 2 data (as we are searching for a pair based on each spot 2. The queues contain peak data (time and amplitude) from a producer/consumer set of loops, and I'm just taking the data from there. I realize this could be done after the fact from a text file, but I would like a semi-realtime update as the experiment progresses.

    So, I think the problem is I need to be able to only operate on new Spot 2 data and the continued influx of Spot 1 data is causing it to run and mismatch, but it could very well be something different, or maybe one of you has a much better idea how I might accomplish my goal.

    Thanks for taking the time to help me out!







    Solved!
    Go to Solution.

    DB:3.22:Time Based Peak Matching Vi 99


    For the most part, re-writing the entire program and taking advantage of more efficient queue structure solved this issue. Thanks for the help!

  • RELEVANCY SCORE 3.11

    DB:3.11:An Efficient Peak Detector aj






    Hi,

    My program requires getting DATA from a DAQ in 16 channels and perform peak detection on all the channels...I used the peak detector vi ...I have that vi. Attached here.It contains only the peak detector vi.

    This peak detector seems to consume too much memory and time ..Can anyone suggest a better and efficient alternative to this?

    Thank you










    Attachments:







    peakdetector.vi ‏6 KB

    DB:3.11:An Efficient Peak Detector aj


    Can you post your acquisition code as well? Are you using continuous mode acquisition?

    I'm not sure I understand this part:

    "i need to filter certain peaks, these peaks will appear assinusoidally varying in amplitude, so i hve to filter the ones in the middle."

    Can you explain it a bit more?

    "the problem is , as i am obtaining data from a DAQ, i have to finish the operations before the next set is available at the DAQ, otherwise it displays an error saying not enough memory."

    Does the error say that the DAQ buffer is out of memory or are you getting a general LabVIEW out of memory error?

    Your consumer program looks ok except you're probably only seeing the last data set since your indicators are inside of your for loop. Are you calling programPD as a subVI? If so you should wire up the connector pane and pass out the data that you intend to use.

  • RELEVANCY SCORE 3.10

    DB:3.10:Missing Peaks In Waveform Peak Detection.Vi ak





    Hi there,

    Although there are quite a few questions relating to peak detection in Labview, I could not manage to find a solution to this problem in the posts.

    I am acquring signals fromtwo channels of USB 6008 DAQ at 1000Hz, one of the channls gives a finger pulse signal which helps measuring heart rate. I am filtering and processing this signal and then passing it to the waveform peak detection.vi.

    There are two problems here.
    The first issue is that waveform peak detector.vi misses peaks sometimes and this seems to be random as there seems to be no obvious difference in the peak missed as opposed to peak detected.
    The
    sampling rate is 1000 samples /second and buffer size is 500 so every half a second
    the data is passed to peak detector vi and the width is 350. I have selected thsi width randomly as this seemed to work. The peak detection works fine for signals where the peaks are at 60-70 HZ but the VI
    misses peaks when signal is 50Hz and it misses peaks randomly. Don't know how to get rid of this.

    Any
    ideas what could be hapenning. I have attached the signal + peak for
    reference. Note that this picture does not have a missed peak as it occurs randomly

    The second issue is that the detected peaks do not correspond to actual peaks. I think
    this is beacuse of the high width. If I reduce the width, I can detect the
    proper peak but I also the second small peak in the signal.Any ideas how this can be sorted. I tried reducing the width and putting condition on the second width, but since the data is real time and continuous, this doesnt work always and sometimes proper peaks are missed.

    Dont know what to do.

    Also attaching the VI jpg.










    Attachments:







    a.jpg ‏67 KB

    DB:3.10:Missing Peaks In Waveform Peak Detection.Vi ak


    Hi Coq Rouge,

    Thanks for the replies. I went through the detailed help but never really got the width concept clear. I have got the ASPT on university discount and am using it to calculate PSD of the rr plot.

    I have access to the Wavelet function for peak detection but it too has a width variable. I will play around to find the best combination.

    In the meantime I am attaching some raw data here. I want to detect peaks here. Note that each pulse signal has a peak followed by a smaller peak that is not of interest as you will gain from teh pics posted earlier. Can you please suggest a good way of detecting these.

    Since teh samling rate is much higher than necessary, I was trying to downsample but get an Error 1801. HEnce I gave up downsampling and used this signal to detect peaks.

    All ideas welcome.

    What would I do if I didnt have experts here to assist me.

    Thanks










    Attachments:







    sample.zip ‏54 KB

  • RELEVANCY SCORE 2.99

    DB:2.99:Memory Allocation mf



    Hello,

    I'm building an application with many sub VI's. This application is reading data from DAQ. When user hits Start button sub vi starts and, using software triggering, waits for valid peak. After peak is detected reads some more data (how much is user dependent- user configures before). If peak is not detected reads constantly data and stores it in a queue using lossy enqueue element.

    Any time I hit Start the memory usage increases about 25MB.

    Every time user hits Start, one sub vi obtains Queues (2, one for history data, before peak and one for data after peak is detected), these queues are passed to another vi that builds one array of data from both queues and destroys queues.

    How to find where this memory disappears?

    I added Execution Trace that contains events from 3 hits of start button.

    Thank you,

    Przemek










    Attachments:







    Performance and memory.png ‏44 KB

    DB:2.99:Memory Allocation mf


    HelloPrzemek.

    I suggest you to use some additional tools that will show you what is happening with memory of your VI.

    Firstly, you can read about vi memory usage here:http://zone.ni.com/reference/en-XX/help/371361H-01​/lvconcepts/vi_memory_usage/.

    To see where on your block diagram LV allocates memory use Show Buffer Allocations Window (you can read about this tool herehttp://zone.ni.com/reference/en-XX/help/371361G-01​/lvdialog/show_buffer_alloc/).

    Also try to use Profile Performance and memory Window (http://zone.ni.com/reference/en-XX/help/371361H-01​/lvdialog/profile/).

    Use those tools as starting point and try to figure out what part of code is causing to have behavior you are interested in.It is a little bit hard to debug application from print screens. Also, I think that you should a little bit better describe what are sub-vis in your main vi (e.g. what rest of block diagram prints screens exactly present).It would be better to have vis, but as you mention your application is quite a big and that is probably why you did not post vis. If you can extract part of your application that replicate behavior you are interested in, it can be usefull for us who are trying to assist you. Did you try to use those tools that I mention?

    Best regards,

    S.P.

  • RELEVANCY SCORE 2.94

    DB:2.94:Deleting Peak Values Detected By Peak Detector Vi mz


    Hi,

    I m using the peak detector vi to detect peaks every 100 samples, if the difference between two consecutive peaks is greater than 15 i want to delete the peak with the higher amplitude only. This data set, should be plotted again on another waveform. I m able to detect peaks that have amplitudes greater than 15, but I dont kn ow how to delete only these peaks.
    Attached is the waveform, with a single peak with high amplitude which I want to delete.

    Any help would be appreciated.
    Thank you.

    Regards.









    Attachments:






    peak_detection.doc ‏88 KB

    DB:2.94:Deleting Peak Values Detected By Peak Detector Vi mz

    Hi Prakruthi,please have a look at this forum thread:http://forums.ni.com/ni/board/message?board.id=170​message.id=69416requireLogin=FalseIt contains a complete VI for deleting peaks. You only have to insert one more condition to deal with the "only peaks with difference 15" requirement.Regards,Johannes Bauer

  • RELEVANCY SCORE 2.91

    DB:2.91:Pulse Wave Analysis k3



    Hi, I'm having a little trouble with this VI that I'm working on and I'm hoping someone could help me. What I'm trying to do is detect the two peaks from a pulse wave measurement file. Each pulse cycle has two peaks and I want to get the times of the peaks. I can get the first higher peak, but I can't seem to get the time for the second peak, which you can see in waveform chart 2. That is the only thing I need to get and I appreciate whoever can help me. Thanks.







    Solved!
    Go to Solution.

    DB:2.91:Pulse Wave Analysis k3


    is this what you are looking to do?




    TimJohnson ControlsHolland Michigan

  • RELEVANCY SCORE 2.87

    DB:2.87:How To Calculate Heart Rate In Simple Way By Using Visa Serial j1



    I am new in Labview, this is my mini project title " PC based ECG monitoring". In this miniproject, i have hardware part which are ECG circuit and DAQ (MPLAB) and will using Labview for graphic user interface. my problem is, i have done the chart for the ecg monitoring, and i need to calculate the heartbeat and detect bradycardia and tachycardia. for bradycardia is more or equal to 100bpm and for tachycardia is less than 60bpm. for the 2 diasease, when it is either bradycardiaor tachycardia, the alarm will light up. i also have a problem to do the peak detection and mark all the maximum and minimum peak and put the location of the peak. thanks. here i got attach my vi.







    Solved!
    Go to Solution.

    DB:2.87:How To Calculate Heart Rate In Simple Way By Using Visa Serial j1


    So it's the solution to read 135 values from device, but to use only the first one???




    Best regards,GerdWCLAD, using 2009SP1 + LV2011SP1 + LV2014f1 on WinXP+Win7+cRIOKudos are welcome

  • RELEVANCY SCORE 2.86

    DB:2.86:Control Amplitude Of Vibration 9p



    Hello, friends.

    I am searching a vi, that can return a average value of amplitude (or peak to peak value ) of vibration signal (a sinusoidal signal) in a certain period of time, for example ,1S, 0.5S. I have used the '' Amplitude and Level Measurement.vi'', but it only return the difference between maximum positiv value and minimum peak value. it is, however, not a average value. can you give me some advise?

    thank you very much.




    major: Precision Mechanics and Microtechnology

    DB:2.86:Control Amplitude Of Vibration 9p


    Hey Gyver,

    I would use the Waveform Peak Detection VI in the Waveform Monitoring VIs Pallette. It finds the locations and amplitudes of peaks and valleys inSignal In andoutputs an array of all the amplitudes of each peak. You can then average that array using the mean VI. Let me know if this helps!

    Regards,

    Cindy

  • RELEVANCY SCORE 2.85

    DB:2.85:Bug? Strange Behaviour Of Lm Nonlinear Curve Fit Vi When Used For Lorentzian Fit f1



    Hi there,

    I am in need for some help in the LM nonlinear curve fitting.

    I want to do Lorentzian fit to a set of data using the LM nonlinear curve fit VI, and get the optimum peak parameters (peak frequency, peak height and HWHM).

    I coded VIs for thistask inLabView 2011 environment. Pleasedownload the VIs named "LMFitTest.vi" and "Lorentzian.vi", attached to this post below, and run the first one.

    As you can see, the LM nonlinear fit VI does not do the job right,givingthe fit results far from the optimum.

    However, if the input data is multiplied by a factorlarger than 1e6 (please type in this or a larger value into the control labeled as Scale factor), then the

    LM nonlinear fit VI works fine,giving the optimum peak parameters.

    As you can see in the block diagram of my VI,the input data is simply multiplied by the scale factor, LM fit is performed on it and the results are divided bythe

    scale factorwhen being spit out. Nothing more.

    So my questions are,

    1) Is it a normal behavior of the LM nonlinear fit VI? Why doesit work only for large input values?

    2) What conditions need to be met in order for this VI to work?

    I spent days to figure out what was wroing with my VI, and finally found that the LM nonlinear fit VI does not work if the input data values are small.

    It was a big waste of time. I believe what I am trying to do is a very common task so the answer for this question should be helpful for many other people.

    Your help on my question is very much appreciated!










    Attachments:







    LMFitTest.vi ‏22 KB

    DB:2.85:Bug? Strange Behaviour Of Lm Nonlinear Curve Fit Vi When Used For Lorentzian Fit f1


    Hi there,

    I am in need for some help in the LM nonlinear curve fitting.

    I want to do Lorentzian fit to a set of data using the LM nonlinear curve fit VI, and get the optimum peak parameters (peak frequency, peak height and HWHM).

    I coded VIs for thistask inLabView 2011 environment. Pleasedownload the VIs named "LMFitTest.vi" and "Lorentzian.vi", attached to this post below, and run the first one.

    As you can see, the LM nonlinear fit VI does not do the job right,givingthe fit results far from the optimum.

    However, if the input data is multiplied by a factorlarger than 1e6 (please type in this or a larger value into the control labeled as Scale factor), then the

    LM nonlinear fit VI works fine,giving the optimum peak parameters.

    As you can see in the block diagram of my VI,the input data is simply multiplied by the scale factor, LM fit is performed on it and the results are divided bythe

    scale factorwhen being spit out. Nothing more.

    So my questions are,

    1) Is it a normal behavior of the LM nonlinear fit VI? Why doesit work only for large input values?

    2) What conditions need to be met in order for this VI to work?

    I spent days to figure out what was wroing with my VI, and finally found that the LM nonlinear fit VI does not work if the input data values are small.

    It was a big waste of time. I believe what I am trying to do is a very common task so the answer for this question should be helpful for many other people.

    Your help on my question is very much appreciated!










    Attachments:







    LMFitTest.vi ‏22 KB

  • RELEVANCY SCORE 2.79

    DB:2.79:Scale Invariant Geometric Pattern Matching Error 3m



    I am looking to create a VI which does pattern matching which is scale invariant, that is

    If I creat a template which is smaller ot bigger than the target image it shoudl be able to

    recognize it,no matter what. I created a vi which is attahced to this post. I am receiving an

    error saying that this template doesnot have information for scale invariant matching. I am attching a snapshot of that too. The real time time image also is posted along with the template. Anyone.







    Solved!
    Go to Solution.

    DB:2.79:Scale Invariant Geometric Pattern Matching Error 3m


    Muks

    you asked me to create a line profile using a bounding box.

    I am not able to open the attachment you posted. can you

    a screen shot of what you did.

    Also neglect posts 5 to 9.My systemin the lab waslogged

    into a different profile. Sorry for the commotion if you are

    still not laughing.

  • RELEVANCY SCORE 2.78

    DB:2.78:Measure Ac Peak To Peak In Labview Basic 9s



    Hii am looking to measure the peak to peak voltage of an ac signal in labview basic 8.6.

    Unfortunately I do not have the amplitude and measurement levels express VI. which does this queit nicely.

    Is there another way to measure the peak to peak voltage of an ac signal just like this vi can? Is there a vi posted somwhere which i have not found which someone has solced this issue before.

    Thanks in advance for any help or assistance.

    Kevg

    DB:2.78:Measure Ac Peak To Peak In Labview Basic 9s


    Hi,

    Thanks for the code it did the trick alright. But noise is a small bit of problem but iam goingtorun a loop and sample over a period of time and average the values, this should limit the noise variations of the signal.

    Thanks

    Kevg.

  • RELEVANCY SCORE 2.77

    DB:2.77:Built-In 2d Peak Finder? d7


    I was wondering if LabVIEW has a built-in 2D peak finder. I found something called "Waveform Peak Detection.vi" that finds peaks of a 1D waveform, but no equivalent VI that finds peaks in a 2D array of data.Thanks,Allen

    DB:2.77:Built-In 2d Peak Finder? d7

    Yes, Allen. That is correct. Is that going to work for your application?



    Amanda HowardAmericas Services and Support Recruiting ManagerNational Instruments

  • RELEVANCY SCORE 2.74

    DB:2.74:Peak Time 8z



    what time is peak time weekdays and weekends? are my landline calls free off peak hours??

    DB:2.74:Peak Time 8z


    Hi bombesly45

    Thanks for your query. To answer your question; the package that you are on gives off-peak Local and National callsfor free from 6 am in the evening until 8amthe following morning on weekdays and those calls are free from MidnightFriday to Midnight Sunday also.

    In relation to the efibre plan, the advertised price would include all taxes soyes this is the total cost of the bundle.

    For information on efibre bundles or to order the service you can also call efibre sales on 1800 503 303.

    thanks

    Colm




    _________________________________________________________________________Common questions answered here!Click here to PM me

  • RELEVANCY SCORE 2.73

    DB:2.73:Control To Blink When A Comparison Of A Peak Load And The... aa


    control to blink when a comparison of a peak load and the currentload, current is less than the peak stop button blinks red .I want to improve my application by putting a stop button control toblink when a comparison of a peak load and the current load is made,when current Load is less than the peak the stop button blinks red .Any help would be greatly appreciated.Perhaps even a example vi in version 6.Thanks

    DB:2.73:Control To Blink When A Comparison Of A Peak Load And The... aa

    See if this attached VI gives you some ideas. It uses a property nodeand shift register to compare two numbers and set the switch blinking.Not too sure about making it red though...









    Attachments:







    blink.vi ‏17 KB

  • RELEVANCY SCORE 2.73

    DB:2.73:6i Can't Find Waveform Peak Detection Vi. Load Error Code 20 d3


    6i can't find waveform peak detection vi. Load error code 20

    DB:2.73:6i Can't Find Waveform Peak Detection Vi. Load Error Code 20 d3

    The waveform peak detection VI is found only in the Full and Professional development systems. Do you have the base package?

  • RELEVANCY SCORE 2.73

    DB:2.73:Regrading Peak Detection Vi Input zc



    I would like to use this peak detection but i would like to remove the signal source and use my own input instead. Could anyone teach me how to do it? thanks^^










    Attachments:







    Peak Detection and Display1.vi ‏37 KB

    DB:2.73:Regrading Peak Detection Vi Input zc


    The input to the peak detector VI is a simple DBL array. I would recommend you use Peak Detector.vi instead of the unexposed subVI in your code (from the biomed toolkit?).

    Where are you getting your data? How you get from there to the peak detector will depend on this, since your data type could be dynamic data type, waveform, or simple array. When in doubt, search the LabVIEW help first.




    This account is no longer active. Contact ShadesOfGray for current posts and information.

  • RELEVANCY SCORE 2.69

    DB:2.69:Settting Up A Audio Functions Based On A Moving Average Through Real-Time Data Streaming 8c



    Dear Labview community,

    I am a currently a studentwho has a limited computer coding background. I have just completed theonline core 1 course and i amin the process of understanding labviews functionality and processes. However, i am under pressure to start testing due to a strict time schedule to get my thesis written up.

    I have created (with a little help) a labviewvi (version 9)which calls for one double data each time the iterationrun(labview calls the data from a separate piece of software that is streaming the data in via a dll plugin).The streamed data (volts which is converted to acceleration G’s in the vi)of which is impact accelerationsof treadmill running over a prolonged time period. The data has continuous peaks followed by oscillation’s of returning to zero acceleration. In thevi, the audio/Boolean indicatorsare currently based on thresholds from each impact accelerationvaluebeing streamed in. However, the Vi contains a peak detection part which is setup to ignore these immediate noisy oscillation peaks that set off the audio sounds un-rhythmical. I don’t quite understand this part of the vi as the guy from engineering set this up. Then In VI there is also a moving average which takes into account the previous 5 impact peaks. The thing is I want to be able to setup the audio/boolean feedback based on the moving average change. The problem is that I don’t know how to connect the audio functions with the moving average and also the audio sounds are constantly on, due to moving average value being constantly above the set audio thresholds. How can I sound the audio/buzzer only when a new peak has been added to the average value data?

    Can anyone correct my VI to get me up and running (excuse the pun)?

    Im desparate

    Kind regards,

    Adam







    Solved!
    Go to Solution.

    DB:2.69:Settting Up A Audio Functions Based On A Moving Average Through Real-Time Data Streaming 8c


    Glad that is working for you now

    Please set up a new forum discussion for questions not related to this discussions subject. Or search the forum for existing related discussions.




    Jack. WApplications EngineerNational Instruments

  • RELEVANCY SCORE 2.68

    DB:2.68:Trigger Help x9


    I am trying to record times when waveform meets certain condition, =0 and dy/dt0. The waveform consists of a sin wave with a gap in it 1/4 of the time which indicates the engine is at TDC.

    With help i have a vi that produces a simulation to the wave i will eventually take from the crank sensor on the engine (attatched). I have produced a square wave from that wave which rises when the conditions above are met.

    I have also been given a vi that records the peak times and time between teeth which is very close to what i want.

    http://forums.ni.com/ni/board/message?board.id=170​message.id=139382 peak time recorder

    What i need is to record these times when the conditons are met rather than the peak times.










    Attachments:







    wheel.vi ‏664 KB

    DB:2.68:Trigger Help x9


    There seems to be a parallel thread about the same thing. Let's keep it all in one place and continue over there!



    LabVIEW Champion . Do more with less code and in less time .

  • RELEVANCY SCORE 2.68

    DB:2.68:Functions Available In The Blackfin Module 39


    Hello,

    I'm trying the Blackfin module to check if it fulfills what I need for my application.
    I need to do some peak detection in several signals and I was very happy when I saw that I still had my time domain analisys vi's when I changed the target for the evaluation kit.
    But unfortunatelly the peak detection vi gives me a linker error.
    I saw it was still using the windows dll call, but the peak detect with threshold doesn't return that error.
    Is there somewhere a list with the functions I can use?
    I'm evaluating version 7.1, will there be more functions available for tyhe blackfin?

    Thanks in advance,
    Paulo

    DB:2.68:Functions Available In The Blackfin Module 39

    Hello,

    To check all the blackfin function go to the following help file : C:\Program Files\National Instruments\LabVIEW 7.1 Embedded\help\lvblackfinpalette.chm.

    You will find help for all the blackfin analysis VIs.

    Regards,




    ClémentG

  • RELEVANCY SCORE 2.67

    DB:2.67:Darren's Weekly Nugget 05/15/2006 xm


    Check out the following VI that ships with LabVIEW 8.0 and later:

    [LabVIEW]\vi.lib\utility\MD5Checksum.llb\MD5Checks​um file.vi

    This LLB is available for download on the Developer Zone, but I decided to include it in the shipping VIs in LabVIEW 8.0. It's a great, 100% G-based implementation of the MD5 algorithm for generating checksums. I've used this VI for a couple of purposes. One was to do checksum matching on the files generated by an installer versus the depot files used to create the installer. Another time I used this VI was in a project where I had a pretty complicated parser that was analyzing text files from disk. When I stored the parsed information from the file, I also stored the file checksum. The next time I needed to load the files, I compared the stored checksum against the checksum of the current revision of the file on disk. If they were the same, I used the stored parsed information instead of having to go through the time-consuming process of parsing the file again.

    To learn more about the MD5 algorithm, check out http://en.wikipedia.org/wiki/Md5 .

    -D
    P.S. - To give credit where credit is due, one of my colleagues on the LabVIEW team, Steven Harrison, was the original author of this VI.
    P.P.S. - Check out past nuggets here.



    Darren Nattinger, CLALabVIEW Artisan and Nugget Penman

    DB:2.67:Darren's Weekly Nugget 05/15/2006 xm

    I have been using it as a checksum when transferring (chunking) large files via LabVIEW TCP to ensure the files are correctly reassembled on the receiving end.



    Joe GerhardsteinAverna Test SystemsCertified LabVIEW Architecthttp://www.averna.com

  • RELEVANCY SCORE 2.67

    DB:2.67:Pattern Matching 3c



    Hello,

    I am trying to do pattern matching on real time acquired images.

    I have 10 template images which i saved in a folder. My acquired images are now sent for pattern matching with these templates. But I encountered the problems that the output of "matches" is zero always. I do not understand why the pattern is not matched.

    Run the program object tracking vi

    select "snap", select the ROI,select the folder to save the template createdand press "learn". Now select "match" to start pattern matching.

    Can anybody help to fix it.

    Thank you.










    Attachments:






    test 2011.zip ‏78 KB

    DB:2.67:Pattern Matching 3c


    Thank you for your response.

    To check my program i captured an image and saved it as a template. Now the same image which i saved as template, i gave as input image by selecting image from folder instead of real time acquired image.

    When the input image and template are same the "match pattern 2" should give "No of matches" as "1". But it is giving "0".

    Please run the vi "Main". Select the folder "images" for templates and select any one of the image from the same folder at "Main image path" to check for pattern match.










    Attachments:






    Matching (3).zip ‏669 KB

  • RELEVANCY SCORE 2.67

    DB:2.67:Problem With Peak Detector cp


    I am acquiring a signal and as I visualize it I wish i can evaluate amplitude of peaks in my signal while i am acqiring it.Is it possible to do that while my VI is processing?When my VI runs i do not have any values out of the peak detector(i've set the threshold, the depth, the peaks mode and everything seems to be wired properly...).Actualy it works well when I use 'peak detector' with a signal that i ve been recording before but it seems that i cant use 'peak detector' to make a monitoring of my signal(actually to measure amplitude of my peaks while I am acquiring my signal).I am using LabVIEW, do you think that it would work with the real time module?thanks for your help.









    Attachments:







    test_peaks.vi ‏59 KB

    DB:2.67:Problem With Peak Detector cp

    The problem with your VI is that you are reading one scan at a time. This produces an array of one element which peak detector cannot use. Modify your code to read all the points at once from your DAQ card. Look in the example code if you need help.Jeremy

  • RELEVANCY SCORE 2.67

    DB:2.67:I Encountered A Problem With Peak Detector.Vi: fs


    My sample data array contains 1 large peak and several smaller peaks on both sides of the large peak. Peak Detector.vi didn't detect all of the peaks (width = 3), but some peaks are listed twice in the output arrays 'locations' and 'amplitude'. Could there be something I am doing wrong, or could it be that my version of the vi is corrupted or outdated?

    DB:2.67:I Encountered A Problem With Peak Detector.Vi: fs

    I actually wanted rate Jeremy's later replies in the discussion. But I didn't how to do that.His comments were very helpful.

  • RELEVANCY SCORE 2.66

    DB:2.66:Triggering On Peak Of Ecg Waveform xj



    Hey,

    Basically, Ive got to simulate an ECG waveform within labview and then use it to trigger solenoid valves. For now, I am trying to use the highest peak (Point R) to turn on an LED. Firstly, I could only find an ECG simulator on NI which just returns the shape, and not a continuous wave. So with a lot of help from a member of university staff, I have attached a VI where the data was transformed into dynamic and then the amplitude and data number is constantly being read.

    I have the following problems:

    How can I make the proccess start again after the end of the waveform, as it eventually gives an amplitude of 0 after the data point where the wave finishes.

    How Can I make the led come on from the time the graph is at the middle of the 2nd highest peak till it turns off at the middle of the lowest peak, and stays off untill it reaches the middle of the 2nd highest peak again, and so on....?

    I thought of 2 ways, firstly to find the highest peak and use equations based on the BPM (note: the vi given is for 60BPM) to offset the triggers on the 2nd and lowest peaks. And a much simpler,; to find the requied peaks by finding peaks within a certain threshold range. But how can i look for a peak within a range of amplitudes? The find peaks and valleys function only has one threshold input.

    Thanks in advance










    Attachments:







    Untitled 1.vi ‏60 KB

    DB:2.66:Triggering On Peak Of Ecg Waveform xj


    You do not have any timing data in your lower loop, so it cannot run at a rate proportional to the original ECG data. The .csv file you posted earlier also does not have good timing data. The first 440 data elements in column zero are "00:00.0". I am guessing that your sample rate is 8000-10000 samples per second, but without the actual value if is impossible to get the timing right.

    The minimum (non-zero) wait is 1 ms, so data sampled at rates above 1 kHz cannot easily be simulated at approximately actual time. What is the purpose of the upper loop? Turning Beat 2 on at each peak and off 300 ms later can be done in the lower loop with a couple of shift registers and no local variables.

    I do not understand what you are asking about the combo box for different waveforms. Are you trying to select from a set of predefined files? Are the files all in the same directory or folder? Are other files in that same directory?

    Lynn

  • RELEVANCY SCORE 2.66

    DB:2.66:Simple Load Cell Monitoring Vi 1k


    I am trying to create a simple VI to monitor a load cell that undergoes a significant load spike approx 1 time per second. Ideally I want the program to capture the peak value and display it. Additionally I would like to display a running average of the captured peak values. Can someone help out a Labview newbie? I have attached my best lame attempt so far. Thanks!









    Attachments:







    Load Cell Display.vi ‏192 KB

    DB:2.66:Simple Load Cell Monitoring Vi 1k

    I have attached a picture of what the data looks like, the scale is not right but this is how it looks. I went to take some measurements off the machine but it went down right as I was trying to log the data. Anyway, let me try to better explain what I am trying to do:1) Determine the peak of each stoke. 2) Display the value until a new value is recorded3) Keep a running average of these peak values and display it.I have attached the VI.Let me know if that makes sense.Thanks,









    Attachments:







    Load Cell Display1.vi ‏323 KB

  • RELEVANCY SCORE 2.65

    DB:2.65:Poor Man's Capacity Planning Using Hp Proliant Server Sizer 19



    Hi all,

    I am starting the journey of sizing approximately 30 HP Proliant DL360's and DL380's to a VMWare optimized solution (sizer is HP ProLiant server sizer for VMware ESX Server)

    Workload is AD, Exchange, IIS, SQL, Oracle, System Center OpsMan/ConfigMgr

    How does one calculate Avg/Max Disk IOPS and Avg/Max Network Throughput so I can ensure correct sizing based on HP .xls sizer worksheet?

    I'm going to use the following perfmon counters and running counter logging for approximately 2 weeks on the above Servers.

    Avg CPU Utilization (%)

    Peak CPU Utilization (%)

    Processor\%Processor Time\_Total

    Avg RAM Usage (MB)

    Peak RAM Usage (MB)

    MemoryAvailable Mbytes then subtract amount of RAM.

    Avg Disk Throughput (IOPS)

    Peak Disk Throughput (IOPS)

    PhysicalDisk\Disk Bytes/sec\_Total

    Avg Network Throughput (MBps)

    Peak Network Throughput (MBps)

    Network Interface\Bytes Total/sec

    Thanks to all who read/reply/offer advice.

    DB:2.65:Poor Man's Capacity Planning Using Hp Proliant Server Sizer 19


    This is the shortcut I usually take:

    http://it20.info/blogs/main/archive/2007/11/26/83.aspx

    Massimo.

  • RELEVANCY SCORE 2.64

    DB:2.64:Vi Using Too Much Memory 79



    Hi all,

    I am trying to write a code to peak pick in 2 dimensions on a rather large data file (approximately 1000x72000 points). The results from this should be integer values where each peak has been reduced to its maximum point for further statistical analysis (see attached code). The problem is when this code is run, the VI very quickly eats through all of the available memory and crashes. I am running a system with 3 processors and 4 gigs of ram, and the program has crashed every time after using about 3.5 gigs, so I need to find a way to reduce the memory usage of this VI. Attached is my VI and an example data file. Thanks.

    Eric







    Solved!
    Go to Solution.

    DB:2.64:Vi Using Too Much Memory 79


    You could easy make intensity graphs that are 100x smaller in memory footprint, e.g. by remapping your original array into a 2D array where each dimension is 10 smaller and then setting the axis increment at 10. You could use 10x10 sections and either take that max or the average, for example. and reduce it to a single element in the new array.




    LabVIEW Champion . Do more with less code and in less time .

  • RELEVANCY SCORE 2.64

    DB:2.64:Real Time Cycle Counting Using Peak Detector kp



    Hello All,

    I am relatively new to LabVIEW, and am currently struggling with a small data acquistion project. The goal of the project is to measure the clamping force of a component over many repeated cycles, to determine the loss of clamping force due to wear. This force is being measured using a pair of load cells connected to a NI DAQ system, which seems to be working fine.

    However, I am struggling with some labview programming. Currently, my best program will record the load cell voltages for a set time period, and then create a graph of the load at the end of the time period. Furthermore, I have used the Peak Detector vi to record the peak loads, and also the cycle count, based on the number of peaks. This was very simple to do using the DAQ assistant, and some simple array manipulations.

    The thing I don't like about this method is that there is no realtime feedback; you don't know how many cycles have taken place until the program times out. Would there be any way to make a program that would detect and count peaks in real time? This way an operator could cycle the component until x number of cycles, without having to count on their own. I have tried to accomplish this by using a While Loop around everything, but I end up with gaps in the data, resulting in some load peaks going undetected.

    Anybody have any sort of game plan for me? Thanks for any help.

    Tony

    DB:2.64:Real Time Cycle Counting Using Peak Detector kp


    Simon,

    I gave it a try, and it definitely works well. The only problem I have had at all is the with the peak detector being slightly finicky, and having to adjust the threshold and width regularly to advoid missing or counting multiple peaks, the same as with my VI using the array peak detector. Is there any reason that the waveform peak detector would work better than the array peak detector? I'm not sure if there is going to be any way around that however. One thing I wished I had told you sooner was that I decided to add the two channels into a single waveform, and detect the peaks from that (each channel is a individual load cell measure force on a test block, adding them gives me total force). I tried to add the two waveforms in your program, but I have not been able to figure out how to make the Append All VI work with this.

    I played around quite a bit more after posting my original, and I think I came up with a VI that does something similiar to your's, but definitely not as nice. Take a look if you are curious, and let me know how they compare.I wasn't familiar with the shift registars, but I used a forloopinstead of a while loop to stack the interations into a final array for me.The biggest downside was thatas faras I could tell,I had to wait for the VI to time out before I could export the array data.

    About learning LabView, I actually had a semester long engineering course with quite a bit of labview programming in it, so I learned quite a few basics, although that was already a couple of years ago. Other than that, I have just been playing around and figuring things out. TheLabview help, and contextual help is extremely useful. I have tried looking at some examples and tutorials, butIhave had a hard time finding relevant scenarios, even thoughit sometimes seems like there are too many examples and tutorials to choose from.










    Attachments:







    Load Cell DAQ Combo.vi ‏5 KB

  • RELEVANCY SCORE 2.63

    DB:2.63:Different Results In Harmonic Analisys 9z


    I am analysing data in the same time with the: 1.Harmonic Analyser VI and 2.RealFFT VI-(for getting the 1_sided FFT, than graphing that data to see the harmonics and afterwards I am using Peak Detector VI).The frequency of the main harmonics and the peaks for them from the other VI are pretty different, and so are the peaks and amplitudes. Which method is more precise. Thank you.

    DB:2.63:Different Results In Harmonic Analisys 9z


    We use TCI filters. They have been very reliable the software works like a charm. I think they were called "Trans-Coil" before.

    http://www.clrwtr.com/TCI-Trans-Coil.html

  • RELEVANCY SCORE 2.63

    DB:2.63:Dividing Time Waveform With Its Peak Value cm



    Dear Sir/Madam

    Good Day

    I am collecting real time data from current sensor. I plot it on the graph. Now I need to divide that waveform with its peak to peak value and then need to draw it on graph. Can anyone guide me how to do it. My vi is attached.

    Warmest Regards

    Urfee










    Attachments:







    LabVIEW.vi ‏694 KB

    DB:2.63:Dividing Time Waveform With Its Peak Value cm


    Hi UET,

    did you ever looked at the entries in the "File" menu?




    Best regards,GerdWCLAD, using 2009SP1 + LV2011SP1 + LV2014f1 on WinXP+Win7+cRIOKudos are welcome

  • RELEVANCY SCORE 2.63

    DB:2.63:Graph Peak Detection Problem 8d



    For surface analysis of a sample, I did signal processing and peak detection using inbuilt peak detector .vi . But the problem is in shown peak/valley location... I have attached the screenshot of one run. See there are some peaks(valleys) which are fairly away from the actual graph. I am confused. What might be the reason of this fault? Any idea?

    red blocks-- peaks

    green blocks-- valleys


    DB:2.63:Graph Peak Detection Problem 8d


    I have used the peak detection function in several application. The peak detections will sometimes be inaccurate in amplitude. The reason for this is as I think covered by Kolan and Alain S. I have found the that the locations is more accurate than the amplitudes parameter. So use the locations parameter to pick values from your wave data. This will improve your accuracy




    Besides which, my opinion is that Express VIs Carthage must be destroyed deleted(Sorry no Labview "brag list" so far)

  • RELEVANCY SCORE 2.62

    DB:2.62:Peak Detection( Take 100 Ms Samples?) a8


    Hi...I have a problem using peak detection under Analysis=waveform monitoring. I want to get the real data (ECG data), and detect the peak of the data. Then i want to store the index of the peak into array so that i can measure the time difference between two peaks. my problem is that when i use peak detection, i cannot get the result as above mentioned. Before this i have tried to test the peak detector and found that if it will detect the peak for 100 ms time interval only. SO if i have waveform with f=100 Hz, then it will detect only 10 peaks..Is it correct that this vi takes 100 ms sample for detection? *correct me if i'm wrongAnd since i want to get the real data from ECG hardware, is there any method to measure index of the occurence of all peaks and store it into array? (not only for 100 ms)-I saw the formula in peak detector help : To view the locations in terms of time, use the following equation. Time Locations[i] = t0 + dt*Locations[i]What does [i] here represent?Thanks for the help...Regards,Rismi *newbie...:d

    DB:2.62:Peak Detection( Take 100 Ms Samples?) a8

    Hi,1. I need more details about your desired results....2. You have to send to the "Peak Detection" amount of data. This will be your 'current block of data'. You will decide about its duration and how many samples will be in it.3. The VI you sent, can't help me for trying to help you. Send the measurements file or the simulated parameters so I can try to understand your wishes and your peaks detection.The Bush-Man

  • RELEVANCY SCORE 2.62

    DB:2.62:Indicator Resets Back To Default aa


    Hiya, I have the following vi and want to change everything within the while loop into a subVI. The thing is that when I do this, I get a warning that the code contains an indicator. When I ignored it and ran the subvi from my main application, the indicator (PEAK TO PEAK) resets back to zero every time the subvi has been called. Is there a way how to overcome this, i.e. remember the last value stored until the subVI is called again?Cheers









    Attachments:







    posted.vi ‏242 KB

    DB:2.62:Indicator Resets Back To Default aa

    Your solution worked right away, thanks a bunch!

  • RELEVANCY SCORE 2.62

    DB:2.62:How Do I Use The Peak Detection Vi In Labview When D a8


    esigning a plugin for Datex S5Collect that calls this Labview plugin every 500ms? ie. how to do realtime peak detection when the data is flowing into my plugin VI in realtime? the plugin doesnt show up in S5Collect when i add the peak detection vi to it...The S5Collect software calls the Labview plug-in that I am designing and I am trying to do a real time peak detection in my plug-in, however, since the S5Collect software calls the labview plug-in, i dont know how to configure the built-in peak detection vi in Labview so that it can receive the data coming in from the S5Collect in real time

    DB:2.62:How Do I Use The Peak Detection Vi In Labview When D a8

    esigning a plugin for Datex S5Collect that calls this Labview plugin every 500ms? ie. how to do realtime peak detection when the data is flowing into my plugin VI in realtime? the plugin doesnt show up in S5Collect when i add the peak detection vi to it...What do you mean "real time"? Does the data come point by point. If yes, you may call Peak Detector PtByPt.vi from the palette FunctionsAnalyzePoint By PointTime Domain PtByPt.

  • RELEVANCY SCORE 2.61

    DB:2.61:Peak Detector Vi Issue 1f



    Hi,

    Am using the example vi advanced peak detector and find it does not save the highest peak value. Its close but not the value thats the highest. I've tried adjusting the width.. without success.

    Has anyone solves the issue?

    Thanks........










    Attachments:







    Advanced Peak Detector.vi ‏19 KB

    DB:2.61:Peak Detector Vi Issue 1f


    Hi All,

    Did a thorough search and found this example explaining exactly what i needed.

    http://digital.ni.com/public.nsf/allkb/2B685D5B2A919E2A8625654C006AF03C

    The definition of half of half width of maximum peak/valley is clearly explained in this url.

    Thanks.

  • RELEVANCY SCORE 2.61

    DB:2.61:Deletion Of Arrays During Specific Time Intervals...How To Get It Working? jp


    i am trying to calculate the average peak values in a systolic pressure waveform during a specific time interval. for example, every 5 seconds, i want to average out all the peak values in that interval and after calculating the average, i want to delete the array of peak values. however, what i am finding is that the array is always 0 if i use the delete array in my vi. therefore, the average is always NaN, because the array is empty and there is a divide by 0 error....what should i do? i have been stuck on it for a long time now, thankyou very much"









    Attachments:







    help.vi ‏57 KB

    DB:2.61:Deletion Of Arrays During Specific Time Intervals...How To Get It Working? jp

    It is very difficult to make sense of your diagram, because all the control references are missing, so it is not possible to tell the various data sources apart.Where is the data coming from? How do you prevent race conditions between the acquisition and analysis parts?Overall, the diagram is overly complicated and very hard to read. For example clearing the array does not require reading the old array, measuring it's length, followed by "delete from array", followed by writing back to the array. Why don't you just wire an empty array to it? Same result! :-)You go to tremedous lenght calculating a simple array average, using numerous property reads and indexing arrays inside FOR loops. There is "mean.vi" that does it in one step. (If you only have base LabVIEW, it might not be available (?), so use "Sum" and divide by n. No loop needed). To find the largest element in an array, use "Array Max Min" from the array palette, again in one simple step.I would highly recommend going over some LabVIEW tutorials or look at some of the shipped examples. Make yourself familiar with basic programming concepts such as auto-indexing at loop boundaries. An "index array" wired to the loop counter is never needed.I suspect that your problem is due to a race condition between acquisition and analysis code, but there is no way to tell unless you include all control references and also the companion VI that gets the raw data from the instrument.



    LabVIEW Champion . Do more with less code and in less time .

  • RELEVANCY SCORE 2.61

    DB:2.61:Peak Detect Error s3



    Hey guys.

    I have a problem with my peak detect on a Power spectrum signal. fromhttp://www.ni.com/white-paper/4278/en/I know that

    I would like to havef = 1 meaning that thefrequency at which the acquired time-domain signal was sampled (Fs) has to be equal to the number of points in the acquired time-domain signal (N).

    When i try to do this the peak detect returns theerror 20013the width must be greater than zero and smaller than sample rate.

    this makes no sens to me ?

    When i have Fs = N x 10 it runs.

    I have added the VI that i have problems with ! if you need the whole project I will gladly add that to.










    Attachments:







    Both sensors.zip ‏329 KB

    DB:2.61:Peak Detect Error s3


    Solved I needed to delay my peak detect. I think its becouse the Queue is empty when i start.

    This is what i did.

  • RELEVANCY SCORE 2.60

    DB:2.60:Where Is Threshold Peak Detect Vi ? 1a


    I want to use the Threshold Peak Detect vi, but can't seem to find it in LabView v6i

    DB:2.60:Where Is Threshold Peak Detect Vi ? 1a

    todd;It is under Analyze-Signal Processing-Time DomainYou can always search for a vi. Just "pin" the function pallete and then click in the search button. (See attached image)Make sure you have the right LabVIEW package. The Base package may not include the vi you are looking for.Regards;Enrique Vargaswww.visecurity.com



    www.vartortech.com

  • RELEVANCY SCORE 2.59

    DB:2.59:After Zooming, How Do I Get X And Y Values? da


    I have an instrument that saves data in a simple x and y format. When viewing this data I would like to determine the peak width, height, position and area. I have utilized the peak detector vi to pick the peak and set the threshold, however, I have not been successful at getting the peak width and area for a specific peak. I think my first step is to isolate the data range that my peak resides. So, after zooming on a specific peak, how do I extract the x and y values for that zoomed region and apply them to peak integration and fitting? Does anyone have a sample vi I could look at or is there already a canned vi in Labview to do this?ThanksBrian

    DB:2.59:After Zooming, How Do I Get X And Y Values? da

    Have you tried to use the peak detector vi to search for *valleys* ? That could give you the peak start and end.If you decide to use manual positionning of peaks, you can get the x limits of the graph display using property nodes : Right click on the graph terminal then CreateProperty node. Right click on the property node then PropertiesX scaleRange.You could also use graph cursors (wave form graph or XY graph) : make the cursor legend visible (right click on the graph), then give a name to cursor n°0 (peak start) and cursor n°1 (peak end). Set the cursor to "Lock to points". Get the x and y cursor coordinates using the cursor list property node, as illustrated in the attached example.Once you get the x start and end coordinates, data processing should not be too difficult, but depends on the data type you are dealing with (are the points equally spaced ? Are the data noisy ?..).If your start and end X coordinates do not correspond exactly to experimental data, you can either interpolate through the points or search for the index of the nearest points in the x array (use the Threshold 1D array vi for that, pass the x fractional value (that you got from your windowing zoom) as input, as shown in the second example.Ask if you need more help.



    Chilly Charly (aka CC)E-List Master - Kudos glutton - Press the yellow button on the left...

  • RELEVANCY SCORE 2.59

    DB:2.59:Peak Detection Algorithm For Fpga Labview 9s



    I am in the process of migrating my Labview software of a fiber optic sensor to an FPGA using a single board RIO. However, my program uses the pre-built Peak Detector VI, which contain some floating point math. I was wondering if there were any existing peak detection algorithms out there that uses the fixed-point math, required in the operation of the FPGA. Thanks in advance for your time and consideration.

    DB:2.59:Peak Detection Algorithm For Fpga Labview 9s


    mdnb2,

    Here is a document on our website that talks about Peak Detection Using LabVIEW and Measurement Studio, though it references the VIs that are not available in FPGA, it has interesting information on peak detection in general.

    As far as writing your own algorithm, here is how I would start writing one. Basic Steps :

    1.) Search the array samples to find the top X number of points and their locations.

    2.) Filter out multiple samples on the same peak by removing points close to other points by witdth of Y samples.

    3.) Filter out low peaks by comparing the all remaining peaks to each other.




    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Ben SisneyFlexRIO VV EngineerNational Instruments- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  • RELEVANCY SCORE 2.59

    DB:2.59:Slowness Of Color Pattern Matching Vi 8k



    Hi,

    We're trying to implement a SLAM (simultaneous localization and mapping) algorithm in Labview based on kinect. In order to do so, the mapping robot should spot landmarks in real-time from the kinect image. We found the color pattern matching VI which does exactly what we need but the problem is that it's very slow (about 1.5 seconds for each image and total of 3 images each iteration). Is this the normal time for detecting landmarks in a kinect image? The robot can't map accurately when the iteration is so slow.

    Thanks,

    Rap Master










    Attachments:







    detect landmarks.vi ‏61 KB

    DB:2.59:Slowness Of Color Pattern Matching Vi 8k


    I would try to extract the luminance plane of the image, and use the grayscale pattern matching VIs instead. In addition to being faster, they're likely to provide better results than color pattern matching.

  • RELEVANCY SCORE 2.59

    DB:2.59:Waveform Peak Detector - How To Store All The Peak Locations ka



    Dea all,

    I used waveform peak detector. I need to store the peak location and peak amplitude in two columns. and all the peaks location will appear in the column with real time stamps. How to solve this? Thanks

    DB:2.59:Waveform Peak Detector - How To Store All The Peak Locations ka


    HIghlight execution slows down the execution of the code and lets you see all the values going down the wires.

    Putting probes on wires will show you the values in the wire and when it last executed.

    Putting extra indicators into your block diagram can show you on the front panel the values in wires you wouldn't normally have looked at.

  • RELEVANCY SCORE 2.59

    DB:2.59:Concerns With Gaussian Peak Fit as



    I have been designing an automated data acquisition/analysis program for lab work that I am involved in. We are running with LV8 and as such, there was a variety of ways to do Gaussian fitting that is needed in our analysis. We have moved away from both of the native fitting routines in Labview for a couple reasons. I have some concerns about the Gaussian Peak Fit vi that comes with LV8. The most obvious is that the gaussian model it is fitting is notvery useful in an experimental setting where a zero baseline is difficult to get. To use this fitting routine, the data needs to be offset corrected before performing the fit, and this adds unnecessary complexity considering the simplicity of adding an offset parameter to the model. Unfortunately, the details of this function are hidden in an external library function call. Another problem I noticed while using this is that the parameter mu shows up as the location of the actual peak value of the dataset rather than an interpolated value. For discretized data that can be noisy, the datapoint with the maximum depth is usually not the actual peak of the gaussian. This happens in each fitting mode when I supply X-Y without providing initial conditions. If I do provide initial conditions, the values I supply are not altered significantly if at all. Using the same inputs and initial conditions, the Nonlinear Curve Fit vi does a much better job at fitting both the offset and peak (mainly because it is a user-supplied model). However, I have found this VI to be considerably slower than Gaussian Peak Fit, and it seems to suffer from problems of its own (http://forums.ni.com/ni/board/message?board.id=170message.id=184873). I have since went to using an external library I built containing a public domain Levenberg-Marquardt algorithm implemented in C. Direct substitution of this where both Gaussian Peak Fit and Nonlinear Curve Fit used to be does not show these problems while at the same time increasing performance. Ifanyone can show me the error in my ways,I would be greatly interested. Although I havefound a way out, it would be considerably easier to usethe native LabView functions for Gaussian fitting rather than integrating a separateC routine to do this, especially since LV8 went a long way in making this functionality more accessible.I havealinktodebug codeI am using for Nonlinear Curve Fit.vi in the link provided above. The same code can be used with Gaussian Peak Fit vi.

    Brian.

    DB:2.59:Concerns With Gaussian Peak Fit as

    Here is a timing analysis comparing the two methods of Nonlinear Curve Fit and the call to the external C library function:

    Nonlinear Curve Fit (formula string): Average time = 202 ms.
    Nonlinear Curve Fit (referenced VI): Average time = 10 ms; mode = 8 ms.
    external library function call: Average time 1ms;

    These were done on a PIII, 930MHz w/256Mb RAM. The averages were out of 25 separate runs.

    Brian.

  • RELEVANCY SCORE 2.59

    DB:2.59:Peak Detection On Tracking Basis kd



    Hello everyone,

    How can i track indiviusal peaks in a signal coming as an array.

    I have already used the peak detector vi but it takes the complete array as an input, but i want to work on indiviual peaks.

    Can anyone pls help me.

    Thanks

    DB:2.59:Peak Detection On Tracking Basis kd


    Thanks for replying

    I have waveform as 1D array, but the waveform in the 1D array vaires in its peak volltages and therefore the calculations changes, what i want to do is to track indivisual peak rather than the complete set of waveforms present in the 1D array.

    Regards

  • RELEVANCY SCORE 2.59

    DB:2.59:Problem In Calculating Time Between Peak To Peak And Valley Current kk



    Master, I want to calculating time between peak to peak and valley current (more details can be seen in the picture: How to calculate time in A area and B area and compare them?). I use Arduino and VISA.I've tried using "Peak Detection" "Amplitude and level measurements" but it all does not work. Please help Master. Thank you in advance.

    I attach my vi and graphic images output from my Arduino. Thank you.

    Sincerely.

    rmfajar










    Attachments:







    coba4.vi ‏177 KB

    DB:2.59:Problem In Calculating Time Between Peak To Peak And Valley Current kk


    If you cannot output your data as an array, there is nothing I can do. Figure out a way to put your data as an array into the peak detector vi. Good luck




    Marc DuboisHaroTek LLCwww.harotek.com

  • RELEVANCY SCORE 2.59

    DB:2.59:Array Waveform Peak Detector 8s



    Hello everyone,

    I am having problems trying to work with the peakdetector tool .. I have a file that contains 17 columns the first one is time and the rest are the data .. I split and now Im trying to find the peaks from the first wave .. I search around and I figure out that it is something related on how the peak detector receive the data. Im trying now to convert the files again in an array but only inside labview and I think that is going to fix this problem .. but I cant.

    Please if somebody could help me I will be really great

    In the attachments you could find the .vi file and the excel file to run the program ..

    Thanks ..







    Solved!
    Go to Solution.

    DB:2.59:Array Waveform Peak Detector 8s


    Thanks for the answer ..

    Ok let me explain you something else,

    The experiment have 16 sensors that are acquiring EVENTS(the acquisition happen in other DAQ experiment ... and then the events aresaved in txt files)... (every event have 16 signals that I have to analyze and every event is storage in an individual file). During an experiment it could happen a 100 events or more ... so the idea is to be efficient ... and to split the data after be analyzed is not an option (is gonna take a lot of time).

    So what I am doing right now is to read every event at a time .. then I split the 16 signals .. make my analysis and then stop .. and read the next file .. and so on ...

    For me it would be good if I don't have to start and stop the program for every file .. or in the case that I have only have one graph to analyze one sensor ... I have to start and stop the program to make the next analysis of the next sensor .. That takes a lot of time ..

    I already try the option to make a case for every sensor but it didn't work ... I still have to stop and start to visualize the next graph .. I need something to change on the fly ...

    I think that labview reads only when you Start and is not continuously reading

    Thanks ...

  • RELEVANCY SCORE 2.58

    DB:2.58:Storing Data From Serial Connection da



    Hello All,

    I am fairly new to LabView, I am trying to store and anaylze values from a non-Labview hardware via an rs-232 connection.

    I have two devices on COM1 and COM2 ports. COM2 sends avaluewhich I would like to store in an array. COM 2 points will form a somewhatsine wave within a few seconds.I would like to compare these values live to generate: max and min peak values, peak to peak values, and mean (I know LabView has signal icons for this, I'm just not sure how to wire it up).

    I have attached the vi.

    Thank you for your time and help.

    Kelvin R.







    Solved!
    Go to Solution.

    DB:2.58:Storing Data From Serial Connection da


    The serial connection is irrelevant. What you need to learn is something as basic as a while loop and shift register. If you want to do a continuous write and read, then place a while loop around the VISA Writes and VISA Reads. Using the Run Continuous button is wrong. That is a special debug mode. The shift register can be something as simple as a Build Array where you append a new value each iteration.

    Eliminate those case statements if you are always going to do something. You have configured the serial ports to terminate the read on a termination character so using the VISA Bytes at Serial Port is wrong.

    Before posting again, run the VI so that there is actual data in all controls and indicators. Go to EditMake Current Values Default, save the VI, and attach it.

  • RELEVANCY SCORE 2.58

    DB:2.58:Ac Peak-To-Peak Using A 4060 xm


    I would like to make a peak-to-peak AC voltage measurement, rather than an AC RMS measurement, using a 4060 PXI-based DMM card. Is it possible to make such a measurement? And if so, what would be the best approach to doing so?

    DB:2.58:Ac Peak-To-Peak Using A 4060 xm

    There is not a function for the NI-DMM to measure the peak-to-peak, either in the Soft Front Panel, LabVIEW, C++, or Visual Basic. Assumming that you are measuring a true AC signal, you can calculate the the peak-to-peak by multiplying the RMS value by square root of 2.

  • RELEVANCY SCORE 2.58

    DB:2.58:Which Vi Can Return A Average Value Of Amplitude (Or Peak To Peak Value ) Of A Sinusoidal Signal? p7



    Hello, Friends.

    I am searching a vi, that can return a average value of amplitude (or peak to peak value ) of vibration signal (a sinusoidal signal) in a certain period of time, for example ,1S, 0.5S. I have tried the '' Amplitude and Level Measurement.vi'', but it only return a difference between maximum positiv value and minimum peak value. it is, however, not a average value. can you give me some advise?which vi can return a average value of amplitude (or peak to peak value ) of a sinusoidal signal?

    thank you very much.




    major: Precision Mechanics and Microtechnology

    DB:2.58:Which Vi Can Return A Average Value Of Amplitude (Or Peak To Peak Value ) Of A Sinusoidal Signal? p7


    Try

    Extract Single Tone Information VI
    Owning Palette: Waveform Measurements VIs

    Requires: Full Development System

    Takes a signal in, finds the single tone with the highest amplitude or searches a specified frequency range, and returns the single tone frequency, amplitude, and phase. The input signal can be real or complex and single-channel or multichannel. Wire data to the time signal in input to determine the polymorphic instance to use or manually select the instance.

    with sinus exitation you can get quite far with it




    Greetings from GermanyHenrikLV since v3.1“ground” is a convenient fantasy'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

  • RELEVANCY SCORE 2.58

    DB:2.58:Color Pattern Matching Is Very Slow m7



    Hi

    I tried this code creating one vi application.

    After the testing with USB webcam I have realized that the color pattern matching is very slow. How to increase the speed and to work smoothly in real time.

    Thank you

    DB:2.58:Color Pattern Matching Is Very Slow m7


    Hi tiho,

    I am glad to hear that Your application is working.

    It is possible that you cannot find the object because the lighting changes or the object is seen from a different angle. I would suggest you test it in a controlled environment (for example in the dark with only one light on) and try to change small things like the angle or the light source to see what causes the mismatch.

    In order to do real-time measurements you can use a smart camera for image processing. It is fast and has a real time operation system so you can create stand alone applications if you want to. Here is a link to see what cameras NI offeres:

    http://sine.ni.com/nips/cds/view/p/lang/hu/nid/210​027

    Good luck with Your application and have a nice day.

    Tamas

  • RELEVANCY SCORE 2.58

    DB:2.58:Go Compare..... [Edited] 9m



    Peak time on my Sky connection

    Peak time on my Virginmedia connection

    DB:2.58:Go Compare..... [Edited] 9m


    Click on the image, it will take you to where you can set one up.




  • RELEVANCY SCORE 2.58

    DB:2.58:Peak Detection Problem... 3f


    Hi,I want to collect an analog data ( raw) from
    external device thru USB. I want to save this raw data to binary /
    spreadsheet. Also, I want to plot the data on a graph in real time.
    While plotting the data, as per the peak width and threshhold limit
    settings , i want to detect the peaks. Once the peak is detected , I
    want to give a label / mark with cursor or annotation to the detected
    peak . This label / cursor / annotation should be displayed vertically
    (i.e, the text should be rotated by 90 deg). Also, once the peak is
    detected, I want to compare the x x-axis paramater ( inthis case time )
    with th values in another text file and if a value of X- axis is found
    in the said range then, name the detected peak with corresponding Y
    value in text file. Also, I have to simultaneously enter the detected
    peaks details in a table ( details should include Peak Name ( if
    matched), peak height, start X, Start Y, End X, End Y and Area under
    the curve.Well hope u got what i intend to do. When I tried doing this in Labview, I was not able to...1. Display the peak Lable vertically ( i had used cursors)2. My peak marking was one peak late. i.e, when second peak was detected, my first peak used to get marked.3. According to me the Vi that i had made was not efficient.I have attcahed the snapshot of the vi i made...Can anyone suggest me a solution for this....sample Vi would help a lot...









    Attachments:







    PeakDetectVI.PNG ‏81 KB

    DB:2.58:Peak Detection Problem... 3f

    Detecting Peak is not an issue. Peak are detected properly. Only Marking them gets delayed by One peak. First Peak is detected as soon as signal crosses the threshhold level, but that peak is marked when second Peak is detected...

  • RELEVANCY SCORE 2.58

    DB:2.58:How To Develop Simple Time Based Ramp Driver For Lab View Vi 19


    how do I develop simple time based ramp driver for lab view VI

    DB:2.58:How To Develop Simple Time Based Ramp Driver For Lab View Vi 19


    To open this up to a wider audience, here it is saved as LabVIEW version 8










    Attachments:







    SRI_TimeProportion.vi ‏175 KB

  • RELEVANCY SCORE 2.57

    DB:2.57:Peak Detector Extract Portion Of Signal j3


    hello
    currently i am using usb6008 for signal acquisition. collecting the offline data and process for one set sampled data, it meets what i desire. But when i test it real time(infinite sampled data), collecting the analog signal, it shows error 20013 which related to peak detector. the error message shows peak detector no state. what has really gone wrong?the sampling rate 1k.

    the 2nd question is thatimanage to extract portion of signal.but it can only extract first portion of the first curve of acquired signal. what vi should i used?

    thanks

    happy new year.

    regards

    DB:2.57:Peak Detector Extract Portion Of Signal j3

    Hi heang,The error -20013 indicates that the width supplied for the Waveform
    Peak Detection.vi must meet the requirement 0 width samples.
    It seems like you are acquiring one point at each iteration. Then you are feeding that one sample to Waveform Peak
    Detection with width 1, hence you are getting the error. To fix the
    problem, I would suggest you acquire multiple data points at each
    iteration of the while loop instead, or acquire all of your data first,
    and then find the peaks and write them to a file.Another option is to move the Waveform Peak Detection, Merge Signals and
    Write Peak Data VIs to outside of the while loop. Be sure to enable the
    indexing of your data terminal to be able to
    access the entire data acquired from outside the while loop.Michael K.



    | Michael K | Project Manager | LabVIEW RD | National Instruments |

  • RELEVANCY SCORE 2.57

    DB:2.57:2 Channel Peak Detection And Value Look Up xz



    Hi all,

    I have 2 different sin waves going into channel 1 and channel 2 of an oscilloscope. What I'm trying to do is:

    1. From Channel 1's input determine the time when peak values occur and save them to an array

    2. Then find out what channel 2's voltage output is at times determined from step 1.

    I started doing this project by only using 1 channel where I was able to extract the y data as well as plug it into peak detection.vi.

    However after I merge the two channels together and proceed like I did with 1 channel labview shows disconnected wires due to data incompatability.

    Any help would be greately appreciated on how I can locate channel 1's peak times and plug those time values to determine output values for channel 2.

    Attached is

    1. The single channel peak detection (which works)

    2. 2 channel peak detection (the .vi I need help on)










    Attachments:







    Single Channel Peak Detection.vi ‏33 KB

  • RELEVANCY SCORE 2.56

    DB:2.56:Maximum Frequency Using Power Spectrum 8k


    HI all,so I'm having a little trouble using the power spectrum vi .I have a signal that I'm generating, its a 10 kHz sine wave, and I also have some random white noise in it. I know that the power spectrum will return with a maximum peak at 10 kHz but I'm doing this exercise simply to learn to use labview better. Anyway, so I have this sine wave and I can take the power spectrum and plot it, and I see my nice peak at .1, which I'm sampling at 100 kHz, so .1 corresponds to 10 kHz and all is well. However, I want to not determine this by visual inpsection but rather I want to output from the power spectrum the time corresponding to the peak(in this case .1), automatically. Is there a way to do this? Thank youBen

    DB:2.56:Maximum Frequency Using Power Spectrum 8k

    definitely didn't know about the existence of this function - I went through the other method and was able to get the desired result but it was much messier than this - thanks for the clean solutionBen

  • RELEVANCY SCORE 2.55

    DB:2.55:Threshold Peak Detector For Digital Data j3



    Hi, I have a graph that shows me the digital input, 0’s and 1’s, I am getting across time. Now I want to select data and just take for example consecutives 1’s that have been detected for at least 3 seconds. I found a function that can do that: the Threshold Peak Detector VI, but this is for analog data, isn’t it? Can anyone tell me if there is a function that can do what I need and it is working for digital data? Thanks in advance, Carola

  • RELEVANCY SCORE 2.55

    DB:2.55:How Can I Load Pattern Matching Images Into Memory? 8c


    I discovered this problem by accident when our network went down. I could not run my VI because the .png file used for pattern matching was on a network drive. My concern it the amount of time that is required to read a network file. Is there a way to load the file into memory when the VI is opened?

    DB:2.55:How Can I Load Pattern Matching Images Into Memory? 8c

    By making this change, I was able to shave 300 ms off of my processing routine!Brian

  • RELEVANCY SCORE 2.54

    DB:2.54:Erp 6.0 Sizing jp


    Hi,I want to implement user based sizing but i don't know how to make it.How i will make module based sizing? It is asking low, medium, high. Could you please explain it step by step? st03n doesntshow me module based users.CO-Users in Controlling-PEAK PER HOURFI-Users in Financial Transactions-PEAK PER HOURPA-Users in Personnel Administration-PEAK PER HOURPD-Users in Personnel Development-PEAK PER HOURLE-Users in Logistics Execution-PEAK PER HOURALM/PM-Users in Asset Lifecycle Management-PEAK PER HOURMM-Users in Materials Management-PEAK PER HOURPP-Users in Production Planning-PEAK PER HOURPS-Users in Project Management-PEAK PER HOURQM-Users in Quality Management-PEAK PER HOURCS-Users in Customer Service-PEAK PER HOURSD-Users in Sales Distribution-PEAK PER HOURBC-Users in Basis transactions-PEAK PER HOURTOTAL CONCURRENT PEAK users -PEAK PER HOUR

    DB:2.54:Erp 6.0 Sizing jp

    Hi,Check with your Security team if they maintained any user group or can differantiate users module wise.Table USR02 with field TRDAT will help you to get list of users logged in to perticuler day.it is really difficult to catogarize users modulewise in SAP system unless relevant data is manually maintained in user master record.Regards

  • RELEVANCY SCORE 2.54

    DB:2.54:Acess Elements Of Arrays In For Loop 7c


    Hi,I have a signal ( currently it is simulated ) and I want to detect the peaks in that signal. I want to display a graph of this signal in realtime ( x - axis is time , y - axis is signal ) Also, I have to mark each peak as soon as it is detected ( i am using cursors for this ). Also, I have a text file which contains some names corresponding to time. When each peak is detected, according to the timing in text file ( with certain deviation ), that Peak has to be marked with the corresponding name in text file ( corresponding to the time at which the peak was detected). Also, I need to rotate the text by 90 deg, of that marked peak's cursor. I have detected the peaks and all the information of that peaks is stored in an array. I am facing a problem while marking these detected peaks. The problem is that once second peak is detected , first peak gets marked. I have used shift registers but still cannot solve this issue. Also, I cannot rotate the cursor text by 90 deg.I am attaching my VI, it is very crude as i am still working on it. Any correction in the VI attached which might help me to achieve what I am upto will be appreciated.Regards,









    Attachments:







    XYSimulatorwithClean.vi ‏1297 KB

    DB:2.54:Acess Elements Of Arrays In For Loop 7c

    Nilesshv,

    If youare going to post code to the forum, it might be a good idea to write it with a licensed copy of LabVIEW and not a bootleg one.

  • RELEVANCY SCORE 2.54

    DB:2.54:I Am Looking For A Lorentzian Peak Fit. 3p


    I have to do a lorentzian peak fit for a spectral peak to determine full width at half max and later the area under the curve, I am using Labview 6i with windows 98 on a pc based copmuter

    DB:2.54:I Am Looking For A Lorentzian Peak Fit. 3p

    Hello,I found another discussion thread in the Developer Exchange that mentions a user having success doing Lorentzian peak fits with the Levenberg-Marquardt VI that ships with LabVIEW. Here's the URL to that discussion thread:http://exchange.ni.com/servlet/ProcessRequest?RHIV​EID=101RNAME=ViewQuestionHOID=506500000008000000​7E020000ECategory=LabVIEW.LabVIEW+GeneralAlso in this thread are a few suggestions as to other places to look on the web for peak fitting routines in LabVIEW. I hope this helps you out. Good luck with your application, and have a pleasant day.Sincerely,Darren NattingerApplications EngineerNational Instruments



    Darren Nattinger, CLALabVIEW Artisan and Nugget Penman

  • RELEVANCY SCORE 2.54

    DB:2.54:Peak Detect sc


    Hello!
    I´ve been using Peak Detect vi (version 7.1) to calculate ECG Peaks. I
    noticed that it finds the first peaks allright, but the more the ECG
    curve advances, the more Peak Detect returns peaks distant from the
    real peaks. Could it be that i should change Peak Detect´s width(i
    started with 10), or should i use another vi?
    Thanks in advance,

    Luanna

    DB:2.54:Peak Detect sc

    Hello, Tom, i´ve checked your tip and you´re right, the enhanced signal
    has peaks different from the original signal. Thanks! Well, now i´m
    trapped :-) Do you have any peak detection code, specific for ECG?

    Actually, peak detection is the first problem. The main problem is
    that, after peak detection, i calculate rr intervals and use the RR
    curve to calculate power spectrum(FFT). My power spectrum has many
    peaks, what is not how a RR interval spectrum should look like. I
    thought that could happen because of the shifted time locations, but i
    dont know if it has that much influence over the FFT.

    In short, i´m quite lost... a more precise peak detection algorithm would be of great help.
    Thanks for everything!!
    Regards,

    Luanna

  • RELEVANCY SCORE 2.54

    DB:2.54:Remote Front Panel Vi Different From Startup Vi 17



    Is there anyway to configure a CRIO with a remote front panel based on a VI that is different than the startup VI? If possible how can I configure it?

    I am able to configure the CRIO with a remote panel that uses the same VI as startup VI as show in all tutorials found online.

    When using a different VI for startup and for remote panel, after a reboot I can't get the remote panel to load.

    Thanks in advance for any help.

    DB:2.54:Remote Front Panel Vi Different From Startup Vi 17


    Is there anyway to configure a CRIO with a remote front panel based on a VI that is different than the startup VI? If possible how can I configure it?

    I am able to configure the CRIO with a remote panel that uses the same VI as startup VI as show in all tutorials found online.

    When using a different VI for startup and for remote panel, after a reboot I can't get the remote panel to load.

    Thanks in advance for any help.

  • RELEVANCY SCORE 2.53

    DB:2.53:Peak To Peak Time 17



    Hello,

    I'm using Labview 7.1 and I am having a hard timetrying to calculate peak to peak Time value.

    I am using the DAQ Assistant to aquire a continousanalog signal. I used the example vi "advanced peak detector.vi" to detect the peak valueswhich works great. However, is there a way to find the Time between peaks?I guess what I am trying to do is displaying the difference between the current peak time withprevious peak time of a continous signal.







    Solved!
    Go to Solution.

    DB:2.53:Peak To Peak Time 17

    I tried using the build waveform vi and I did this:I took the "amplitudes" source and connected that to the Y part of the build waveform VI. But after that, I have an error with my build array (not shown below). It seems like its a bad terminal and it's not compatible with the build array even though the wires connect and show no visual errors.
    I also tried using the t0 and dt from the original waveform. Still the same problem with my build array. Am I connecting my build waveform to my build array wrong still?

    Message Edited by immortalc on 06-22-2009 10:02 AM

  • RELEVANCY SCORE 2.53

    DB:2.53:How To Get Time Associated With Max/Min Vi? 8z



    Hi,

    I am recording the Max value of a signal using Max/min vi.

    How do I get a time value corresponding to the Max value of signal?

    ie how many seconds did it take to reach peak value.

    Thanks for help.

    DB:2.53:How To Get Time Associated With Max/Min Vi? 8z


    Thanks for your reply,

    What I am looking for is something to say, it took 3 seconds to reach Max value.

    The system I am running wants to record Max value and how many seconds it took to get to that value.

    These figures are key for my system because I want to improve the system to get a Max value as quick as possible.

    Ideal front panel would be ie,

    Max value 200

    Time taken: 5 seconds

  • RELEVANCY SCORE 2.53

    DB:2.53:Cepstrum jk


    Hello,I'm an italian junior researcher. I'm looking for the real algorithm procedure of the (real)cepstrum to relize in labview. It isn't in the SoundVibration Toolkit, and I have found different notations about cepstrum.The opeartion's sequence would be:fft(ln(fft(signal))))My doubts are:1. The internal fft is a power spectrum, a rms, peak, or peak-yo-peak spectrum?2. The internal fft scale must be linear or in decibel?3. The external fft is correct or must be an inverse fft? I found different notations in contraddiction.4. In the case of external fft, the X scale is time, but it must be converted in frequency to recognize the fundamental frequency (which is the purpose to use the cepstrum). How I can obtain this convertion?Do You know if there exist a Labview Vi that realize the cepstrum, where i can find it? I'm searching in the correct forum? Thank you

    DB:2.53:Cepstrum jk

    Hi mikkyI guess cepstrum vi will be in the next version of "advanced signal processing toolset". Now, it is a beta version. Pwehaps you can ask your local NI representative to get a copy for you.CheersAlipio



    ---------------------------------------------------------"Qod natura non dat, Salmantica non praestat"---------------------------------------------------------

  • RELEVANCY SCORE 2.53

    DB:2.53:How To Represent Peak Detector Funtion With Regular Labview Vi's 8x


    I am trying to build a VI that can do the funtion of peak detector in LabVIEW PDA 7.1 version. Can someone help me regarding this issue. The reason is peak detector does not work in LabVIEW PDA.

    DB:2.53:How To Represent Peak Detector Funtion With Regular Labview Vi's 8x

    Chi,There is a KnowledgeBase that deals with this issue. It is located here.Have a great day!Robert MortensenApplications EngineerNational Instruments



    Robert MortensenSoftware EngineerNational Instruments

  • RELEVANCY SCORE 2.53

    DB:2.53:How Can I Create A Command Based On Peak Values On A Waveform Chart Of A Frequency Response? zm


    The background is that we are using a microphone to capture the sound of acoin hitting a bell. We are able to use LabView to capture the analogvoltage signal and display the FFT of the signal in a waveform. Thetrouble we are having is figuring the proper coding or vi to use tocapture the peak frequency (that is almost instantaneous) so that we canactuate another command based on a peak value that has passed through thewaveform. Basically, each drop of a coin must be paired with a distinctvalue. The waveform is capturing it just fine, but how do you extract itand trigger another command based on this value?
    Howard

    DB:2.53:How Can I Create A Command Based On Peak Values On A Waveform Chart Of A Frequency Response? zm

    Hello Howard,

    There is a signal processing function "Extract Single Tone Information" which will take in a waveform and return the frequency, amplitude and phase of the tone with the highest amplitude. You can compare the results of thisfunction with a particular threshold or value and use a case structure to execute one or more different actions based upon the comparison.

    Hope this helps,

    Jennifer O.Applications EngineerNational Instruments

  • RELEVANCY SCORE 2.52

    DB:2.52:Execute While Loop Based On Different Time Intervals Of Day f3



    I currently executing a program in which I am going to measure the cost of electricity signals during different time intervals of a day. Right now I have created a program in which I get the voltage signal and the current signal to calculate my power (Formula: Power = Voltage*Current). For simplicity, I used 2 simulate signal blocks to act as my voltage and current waveform.The power value I have gotten would be multiplied by the cost of electricity during that time interval of the day. I then record the daily pricing of on a text file in aseparatefolder. Right now I hadsuccessfullyimplemented flat charge pricing of my signals (For the whole 24 hr period).

    The problem I am facing now is implementing peak and off peak pricing during certain time intervals of the day. This means I want to calculate the cost of my signals during the peak period (11am- 7pm) with a certain peak period cost and off peak period (7pm -11am) with a certain off peak period cost. So far I have don't have a clue how to implement my program that is able to execute my specific while loop during certain time intervals of the day

    Would greatly appreciate if some one could guide me to solve my problem

    DB:2.52:Execute While Loop Based On Different Time Intervals Of Day f3


    Attached is the VI that I had done with regards to measure power pricing. Now is just figuring how to execute my while loop during different time intervals of the day Peak Period(7am - 11 pm) Off Peak Period (11pm - 7am)










    Attachments:







    generate cost.vi ‏160 KB

  • RELEVANCY SCORE 2.52

    DB:2.52:Peak Period Minutes ms



    I can't figure out exactly what time the off-peak period starts at night..

    DB:2.52:Peak Period Minutes ms

    Weekends are off-peak. They start from 9.01 PM Friday Night to 5.59 AM Monday morning.

  • RELEVANCY SCORE 2.52

    DB:2.52:Peak Search Outputs Wrong Value s3



    I'm using the peak search VI to trend amplitudes from a power spectrum. The peak search VI is not outputing the correct amplitudes. They are off by a little bit everytime. I have looked at the output arrays from the power spectrum, and I have verified the peak search is getting good input data but outputting something unexpected. I have the peak search set for: 1) Single Max Peak, Threshold=0, Start=57.8Hz, Stop=59Hz and 2) Single Max Peak, Threshold=0, Start=61 Hz, Stop=62.2Hz. Neither one is displaying the correct value. I will post my code, but the file I'm opening is a .dat so I can't post that.







    Solved!
    Go to Solution.

    DB:2.52:Peak Search Outputs Wrong Value s3


    The power spectrum in your top For Loop is not the same as the power spectrum in your bottom While Loop - the two spectra are computed from different time-domain blocks.

    This seems like it could be a source of confusion when comparing peaks to the computed spectrum. What is the purpose of the top loop? bottom loop?




    DougNI Sound and Vibration

  • RELEVANCY SCORE 2.52

    DB:2.52:Acquire Continuous Images sc


    i create a pattern matching VI by using Vision builder 6.1. When i run the VI, the program ask me to select file for ome time. when i run the VI in continuous mode, the program keep asking me to select file. what I want the VI is to import the live images recieve from the carmera and generate the shape report spontaneously rather than asking me to select file. from folders.I attach the VI. I am new to computer programming, vision, LabVIEW Please help Thank you very muchnick









    Attachments:







    PatternMatching1.vi ‏84 KB

    DB:2.52:Acquire Continuous Images sc

    In you PatternMatching1.vi you are using file Dialog vi so when you are running the vi it will ask for the file path every time so you delete that vi and you need to acquire the image from the Imaq card directly.

  • RELEVANCY SCORE 2.52

    DB:2.52:Missing Calculate Peak Moments.Vi cz


    Hello,

    I wrote a VI in LabVIEW 8.0/8.2 which used a vi called Calculate Peak Moments.vi. Now I tried to open my VI, on a new computer, with LabVIEW 8.5 and neither the computer nor I can find the Calculate Peak Moments.vi.

    Can somebody help me, either by telling me where I can find this VI in 8.5 or by sending it to me?

    Thank you,
    Jason

  • RELEVANCY SCORE 2.52

    DB:2.52:Sampling Continuously, Peak/Threshold Detection On Samples, Acting Upon Results. f1



    Hi everybody, I've been stuck with this problem for two days straight and don't seem any nearer to a solution. I would thoroughly appreciate any help any of you could give me.

    As part of the test system I'm trying to set up, I have an analog input signal (50Hz sine, +/-8V, differential inputs) and several digital output signals. By setting one of these digital signals high, a relay (in hardware) is switched on, something goes open circuit, which means the analog input signal goes to zero. So, as long as the digital signal is low, I can read in this sine wave, but when set the digital signal high, the sine wave disappears.

    I'd like to set up a way of setting this digital signal high when the sine wave reaches it's peak (or really, any value above 7.5 is fine) - to achieve, in essence, a cut-off sine wave. Later, the digital signal will be set low again, the sine wave will appear again, and I'll repeat the test later.

    I am having a nightmare trying to get this working. I've experimented with peak detection and threshold detection VI's - the problem is: You can't really 'react' to the peaks because you don't get any information about peaks until the detection VI has finished it's execution. I've tried setting up a while loop with a simple "1 channel, 1 sample" read system (based on the DAQmx Create Channel, Start Task, Read, Clear Task VI's) , and then comparing the single sampled value to a threshold - the problem is, each iteration of the loop seems to take 8ms, which is far too long.

    Since max sampling rates according to specs of the NI-6224 card are 250kS/s, is there no way that there can be a simultaneous 'read-in'/'read-out' system, where I could sample at 1kHz, but keep doing a compare on the value being read in, in real-ish time?

    DB:2.52:Sampling Continuously, Peak/Threshold Detection On Samples, Acting Upon Results. f1

    Hi David, Raajit,

    Raajit, this:"When you configure an Arm Start Trigger, a counter" applies to triggering multiple counters simultaneously - we don't need to do that here.

    This link suggests it is possible to use an analog start-trigger together with a counter.

    Specifically: "If your board supports analog hardware triggering, there is an internal signal that is high whenever the signal on the trigger channel meets the trigger conditions. This signal can be routed to the counter to control it.

    As I said, I haven't done it, but this states it's possible!

    Cheers.

    Message Edited by tbd on 02-12-2007 10:28 PM

    Message Edited by tbd on 02-12-2007 10:30 PM




    "Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

  • RELEVANCY SCORE 2.52

    DB:2.52:Time Of Maximum Chart a7



    I need to draw a chart that shows the behavior of the frequency of the spectral peak of the signal over time. I thought this VI would work fine:

    The interesting thing is that before connecting the Time of Maximum output of the Statistics block to the Time of Max Over Time Chart, the chart shows the settings properly:

    Here is the corresponding Block Diagram for the Front Panel above:

    But once I connect the Timeof Max Over Time Chart to the Time of Maximum output of the Statistics Block and run the VI,the Time (X-Axis) of the chart changes to Frequency X-Axis:

    Again, I want the chart to display the changes of peak frequency value over time. Any suggestions? I attached the VI below. Thanks!!







    Solved!
    Go to Solution.

    DB:2.52:Time Of Maximum Chart a7


    Hello wprice

    I highly recommend creating a new forum post for this issue as it is different from the original issue. This will not only ensure that it gets the proper attention from the community but it will speed resolution and allow users to more easily search for a similar solution should they have a similar issue. Rest assured that this will be assigned to one of our engineers so this is guaranteed to get resolved!

    As a starting point, please consider the portion of this document titled

    Customizing Graph and Chart Appearance from the Customizing Graphs and Charts Help document

    http://zone.ni.com/reference/en-XX/help/371361G-01/lvconcepts/customizing_graphs_and_charts/

    All the best!




    Sincerely,Greg S.

  • RELEVANCY SCORE 2.51

    DB:2.51:Peak Detector - Error -20013 pc



    Hello,

    I'm simulating a DAQ device, and I would like to use the peak detect function, but I'm getting the following error:

    I've attaced my vi, I tried to change the values of width but it doesn't work.

    Can someone help me please?

    Regards







    Solved!
    Go to Solution.

    DB:2.51:Peak Detector - Error -20013 pc


    Thank youLynn for the nice description! now the error is gone

  • RELEVANCY SCORE 2.51

    DB:2.51:Simple Peak Detect am


    I have a waveform that I need to detect peaks valleys on. I use the peak detector VI.
    Attached is my VI with an indicative array of values that I will
    encounter. The peak detector correctly finds the 3 peaks but doesn't
    find the 2 valleys in the middle - I don't undertand why.
    Those are the 2 I'm most interested in - the first last are just tails of the waveform.

    Any help would be greatly appreciated,

    thanks

    ak










    Attachments:







    peak detect.vi ‏22 KB

    DB:2.51:Simple Peak Detect am

    Yes - that does it. Must have been a long week...

    Thanks !

  • RELEVANCY SCORE 2.51

    DB:2.51:Real Time Image Recognition cx



    Hi

    I try to realise real time recognition small objects. I am using Vision assistant. With color pattern matching I create a template selecting the object that I would like to recognise. Than I check if everything is OK with batch processing. Using batch processing after matching of the template with the current image the object is marked with red window. After creating labview VI application and after starting the application the red window doesn't appear. I would like to mark the matching object somehow. How I can do it with labview?

    Thank You

    DB:2.51:Real Time Image Recognition cx


    Hi,

    just input the right path to your pattern png file.




  • RELEVANCY SCORE 2.50

    DB:2.50:Increase Delay But Peak Appears At Earlier Time? fp



    I am trying to work some bugs out of my program and I am having some difficulties.

    The data collection is being done with a NI 5761 digitizer and NI 7965R FPGA module on a PXIe 1071 chassis.

    This is just a very simple VI to collect a signal from a photodiode that is monitoring a laser, and I am trying to change the delay as to when the laser will fire.

    As I try varying delays (0,1, and 2 microsec) my peak actually moves to an earlier time that it is being read. This is completely opposite as to what should be happening and I am thoroughly confused.

    Any suggestions as to why I am seeing this happen?










    Attachments:







    Laser PD_test 2_ver2.vi ‏66 KB

    DB:2.50:Increase Delay But Peak Appears At Earlier Time? fp


    rschmeling,

    Thanks for the new VI. The project would be better so I could see things such as FIFO size, I/O, and not have broken wires everywhere. Also, the number of elements you are reading is Record Size/2, which is only 8,000 points not 16,000 according to your controls default value. For troubleshooting purposes, it might be easier to use constants.

    You say this "The target VI is only triggering the laser once and the data collection and then going to the idle or false state. So this isn't operating in continuous data collection." I disagree with this because the mechanical action of the OK button on the FPGA VI is not set to latched. Because the FPGA VI is so much faster than the Host VI, this code will have executed many times before OK button finally gets written false by the host side. If you want the target VI to only run once, you should set the mechanical action to latch and then create a while loop that polls that boolean value before executing the rest of the code in your while loop when it sees a true. You could also implement a counter in FPGA so you can actually see how many times your case structure is actually executing the way you have it now.

    Also, you are using target to host FIFO, not host to target like you stated. I know it is target to host because you are writing on the FPGA (target), and reading on your host VI. There are two main things which are important when transferring data this way. The first is monitoring the timeout on the FPGA and latching that value should you ever timeout (Once you timeout, you are losing data). This latched timeout boolean should be monitored from your host and act accordingly depending on your application.

    The other danger of DMA FIFOs is getting stale data. The way you are using it, there is potential for stale data (and overflow but as long as we implement correct triggering and perform flushing I think we can get by without monitoring the overflow if the FIFO is large enough). Therefore, you should perform a flush like I had stated in the previous post.

    Please change the mechanical action to latched and create an additional while loop that polls that value before acquiring your FPGA samples. Then, before writing your OK button back to true, perform two FIFO reads. The first read should be for 0 elements and the second read should have Elements remaining from the first read wired into it. It is important that your “Collection iteration count” is smaller than your DMA FIFO to ensure that there is not overflow on the FPGA, otherwise a third DMA Read would be needed that is the size of the FPGA FIFO. By doing this, it will ensure that your data is actually correct.

    I really suspect this to be the case because you are assigning dt values to the array by saying the first value is 0, second value gets dt, third gets 2*dt and so on. If the first value of your array is not newly sampled data, then we would see unexpected results like you are seeing.

    Regards,




    ChrisNational InstrumentsApplications Engineer

  • RELEVANCY SCORE 2.50

    DB:2.50:Power Spectrum Vi Gives Different Peak Amp. Vs Rfsa Front Panel?!? zm



    Hey guys,

    I have a problem that's been bothering me for some time. The issue is that the FFT Power Spectrum and PSD VI gives me a different peak amplitude for test signals that the RFSA soft front panel gives me. Here's what I'm doing:

    I transmit a sine wave at IQ rate of 2MHz, carrier freq. 5.5GHz from a VSG (separate box) into the RFSA. When looking at the spectrum in in the Soft Front Panel application, the height of the peak is -50dBm and very stable. I also tested this by transmitting into our other HP spectrum analyzer, and got nearly the exact same result, -50dBm peak height. So, I am quite confident that this is an accurate measure of the received signal power.

    However, when I try to use the very same RFSA to receive a signal and analyze with a simple labView program, I get problems. I take the output of the RFSA Fetch IQ VI, and funnel it into the FFT Power Spectrum and PSD VI, and plot the result on screen. The spectrum looks as it should, except that the peak height of the sine wave is at -60 dBm! I have the VI set to power spectrum, not PSD.

    Has anyone seen this strange behavior? I have tried at least 5 different methods of computing a power spectrum in Labview, but none of them give me the same peak height as the Soft Front panel, and the spectrum analyzer hardware! Our experiment depends on getting accurate amplitude information, and I feel that there is a problem with how the peak is being computer in the VI, or I am missing something. Could someone experienced with the Power Spectrum VI please help? I need to know how to hook up the Power Spectrum VI such that it gives me the same result as the Soft Front Panel.

    Thanks so much!

    Brian

    DB:2.50:Power Spectrum Vi Gives Different Peak Amp. Vs Rfsa Front Panel?!? zm


    I just posted a seperate post on a similar topic...as I too have been running into issues trying to convince myself I understand what NI's vi's are giving me and what the units really mean.

    I've noticed that if you drill down into the Power Spectrum and PSD.vi....you'll find there's a vi called, "One Sided Power Spectrum". In this vi...there's another VI called "Power Spectrum.vi", that ends in a code interface node. However, the artwork of this vi suggests that it takes in IQ samples, and returns V^2_rms.

    This V^2_rms then goes into the "Convert to dB.vi"...where, with the "Power Spectrum" option chosen, simply does 10*log10(V^2_rms).

    Based on Peter's suggestion....I took the "dB" output from the Power Spectrum and PSD.vi...went back to V^2_rms....then dividedn thatby 50ohms and divided again by 1mW....THEN did 10*log10 of that to get to dBm. However....the "dBm"result is about 10 higher than the "dB" result.....which is leading me to think that the V^2_rms that the Power Spectrum and PSD.vi calculates is already scaled by 50ohms and referenced to a mW?

    Is this possible? As I mentioned, I'm unable to verify this by looking at the code since the VI that does this computation is a CIN.

    ---

    Brandon

  • RELEVANCY SCORE 2.50

    DB:2.50:Measuring And Displaying Time Difference Between Peaks From Two Different Channels da



    Hi,

    I am new to Labview and am having some trouble trying to measure the time difference between the two highest peaks coming from two different accelerometer signals/channels. Other posts have mentioned similar problems but I am still confused and would appreciate any help.

    So far, the two channels are each using the peak detection VI and then a shift register with a Min/Max array which is supposed to detect the location of the highest peak value from each channel. What I would like to know is:

    How to convert of the highest peak locations into units of time. (The conversion I am using is not working)

    How to keep this time difference displayed after sampling has finished

    Any help is appreciated. Thank you.

    Johnny










    Attachments:







    TimePeak_Test2.vi ‏189 KB

    DB:2.50:Measuring And Displaying Time Difference Between Peaks From Two Different Channels da


    I see two distinct waveforms on the Voltage Vs. Timeand Voltage Vs. Time 3 graphs. The Sampled Data indicator shows two different waveforms and the data and data2 indicators shows two different values.

    That appears to be all working (at least on my system). What doesn't work is all of the code you have after. It does not make any sense to me. I don't see where you are getting the time of the peaks. You getting the max voltage of both waveforms seems to guarantee a 0 result.

    You can use the code below. It uses the Basic Trigger L:evel Detection.
    Message Edited by Dennis Knutson on 04-10-2009 03:52 PM









    Attachments:







    Delta T.PNG ‏4 KB

  • RELEVANCY SCORE 2.50

    DB:2.50:How To Get Final Time 7m



    hi everybody we need some help

    we are trying to find the delay the between two signal peak . now i am using ELAPSED TIME VI from the timing pallet that counts the delay,in an increasing manner, and the VI is reseted after the second peak is detected

    but what i need is the exact final delay time instead of the increasing time delay count , can kindly anybody help me.

    DB:2.50:How To Get Final Time 7m


    you can use Elapsed Time VI in conjuction with the tick count. The elapsed time VI will reset with the first peak. But the Tick Count will give you the whole span of time till the second peak when the whole VI is stopped. A minus functionbetween the tick count time and elapsed time VIvalue will give you the time between the two peak.




    RegardsAsad TirmiziDesign EngineerInstitute of Avionics and Aeronautics" Its never too late to be, what u want to be"Using LabVIEW 8.2

  • RELEVANCY SCORE 2.50

    DB:2.50:Onset And Offset Detection kd



    Hi,

    I want to detect the on and offset:

    of the signal attached in de VI.

    I've tried it with a 2nd deritive and then a peak detection, but it just won't work all the time... And sometimes it pick peak, that i don't want because of the noise...

    Does anyone have a better solution for this problem?

    Best regards,

    Thijs










    Attachments:







    DetectOnAndOffset.vi ‏395 KB

    DB:2.50:Onset And Offset Detection kd

    Hi Thicop,I've already figured it out and use a linear fit on the data, see my latest vi, this kills al the noise and gives perfect results. If you have better ideas... very welcome! It is eyemovement data and i only detect within 1000 ms after a stimulus is given, which you don't see here. Then it works great. What is your method?Regards,Thijs

  • RELEVANCY SCORE 2.50

    DB:2.50:Error In Finding Peak Data. kf


    I have two problems. I have data of wavelength intensity. It is a txt file, one row describes wave length, other is intensity, column is 1100. I read this file and have it 2D array. I want to find peaks, but When I use 'peak detector', It does not fit with wavelength. [ it only represents index number,(maybe around 250) I cannot added up index number selectively with original wavelength.(1100 numbers) ]When I use waveform detector, I cannot convert wavelength intensity data to WAVEFORM data. And second problem is that the VI does not read files at all. It only repears one time., not number of txt file. I use 'recursive file list', number of files maybe added with called bkgd files, but it represents the number of file. When I connect this number to a end condition of for loop, It reads 1 by indicator.So, my vi reads only one time and cannot represent any peak data, and read more data than I mean. I try to make this vi for 3 week, but I failed.

    DB:2.50:Error In Finding Peak Data. kf

    maybe this file









    Attachments:







    bkgd3rd.vi ‏129 KB

  • RELEVANCY SCORE 2.50

    DB:2.50:When Is Peak/Off Peak Time? 3x



    I thought after 6 would be off peak, but I've been charged £9.77 for a call starting at 18.02.

    I can't find the information anywhere on MyO2.

    Can anyone advise please?

    Thanks

    Dot







    Solved!
    Go to Solution.

  • RELEVANCY SCORE 2.50

    DB:2.50:Peak Finder zj


    hi all,

    I'm currently working on a peak-valley (through) finder on EMG Data. ButI can't automatically find peaks and valleys... Could somebody please have a look at my VI?

    I Highlighted the area where I’m doing the peak valley analyses...

    My Final goal is to take all the peaks as one point, and plot another line over those maximal datapoints to create a peak (or valley) line and calculate the slope of that function.

    Does anybody perhaps has another way of doing this, or am I just totally out of track and doing the wrong thing?

    Thanks for investing your time… J










    Attachments:







    Peak Valley another go.vi ‏1181 KB

    DB:2.50:Peak Finder zj

    Hi MrHond (or MrDog),

    Whydidn't youconnect the threshold and width (peak) inputs ?

  • RELEVANCY SCORE 2.50

    DB:2.50:Keyence For Angular Measurements 9f


    First off, I'm by no means a veteran of LabVIEW. I've had it for about a month now.

    Anyway, I'm working on a VI to process the output of a Keyence laser measurement tool.
    The laser will be targeted perpendicularly at a point n-millimeters from the axis of an oscillating motor.
    The VI should measure Frequency, peak-to-peak amplitude, evaluate amplitude against a limit, represent all this on a graph, and other various small tasks as needed. All based on a DAQ reading of the laser output.

    I have already made some progress on it but I do not know how well it will perform on other, possibly slower, machines. Also, I already figured out that a node really slows down my execution by several times, and I'm wondering what other things could be done to optimize the speed of the whole loop.

    If anybody is willing, could you tell me how it performs on other machines? I am looking to keep the loop execution under 2 mS total, but I want to be able to do that while adding another laser. Your feedback is appreciated, but there is not a time crunch. Thanks!



    ____Ryan R.RD

    DB:2.50:Keyence For Angular Measurements 9f

    I have LabVIEW 8.5.1 Full.

    I was thinking the same thing on the limits, so I will probably move the code outside the main loop.Right now, it can be handy to change them on the fly for testing, but in the final application, the limit wouldn't need to be changed for days, weeks, or maybe more. That shaves off about 10 µS each iteration, IIRC.

    Thanks for the feedback!



    ____Ryan R.RD

  • RELEVANCY SCORE 2.49

    DB:2.49:Dfd Iir Notch Peak Design Vi zf


    I'm trying to make a sharp notch-type digital filter to remove the 60 Hz frequency noise in my signal. The NI Digital Filter Design User Manual shows an easy and efficient way of doing it using the DFD IIR Notch Peak Design VI. I downloaded the Digital Filter Design demo to try it out. The problem is that I cannot find the Notch Peak Design VI among the demo files. Is this VI part of a library that you only get if you purchase the Digital Filter Design toolkit?

    Thanks,

    -- Ilkka L.

    DB:2.49:Dfd Iir Notch Peak Design Vi zf


    Hi..

    I have taken an patient ECG from DAQ and given to the normal LPF and when I connect an notch filter to normal LPF filter is not getting connected and showing a wire connection error.

    I am trying to get the output in graphical waveform.

    Please help me to sort this out.










    Attachments:







    21.jpg ‏71 KB

  • RELEVANCY SCORE 2.49

    DB:2.49:Peak Detection And Find Time Difference Between Two Graphs jj



    hi.

    Basically i have two different graphs with phase differnece of 90. the problem is that using XY graph, i find it really hard to figure out thetime differnece between the peaks. it should be first graph's peak value- peak of second graph. the time differnece much be constant as you can see from running the VI. iam getting some different values too.Is it possible to plot those on waveform chart?. if is possible then can you please show me how to do so.

    thanks










    Attachments:







    PeakDetection.vi ‏45 KB

    DB:2.49:Peak Detection And Find Time Difference Between Two Graphs jj


    yea sorry. i put it on the wrong place. i dont know how to delete this post..

  • RELEVANCY SCORE 2.49

    DB:2.49:I Would Like To Detect The Peaks Of A Modulated Signal Using Only The Threshold Level Rather Than The Threshold Level And The Pulse Width. dz


    I would like to measure the peaks of the modulated signal using the threshold level rather than the threshold level + the pulse width as in the labview peak detector Vi program. Since my waveform is continuously changing, it is hard to predict correctly the pulse width, Examples of the waveform are shown in figure 1. Y axis is amplitude and the X-axis is time in milliseconds. Looks like pulse width is crucial thing in the peak detector Vi. Based on the pulse width, the peak position changes. I was wondering if anyone has solved these issues based on the +Ve and -ve slope crossing the threshold level rather than the using the pulse width. We are using Infinium 500 digital Oscilloscope to detect these signals and analyzing it









    Attachments:







    Peak detection signal.doc ‏38 KB

    DB:2.49:I Would Like To Detect The Peaks Of A Modulated Signal Using Only The Threshold Level Rather Than The Threshold Level And The Pulse Width. dz

    I have a Std Deviation and Mean vi (same as I use in 8) under LV 7.1 located in AnalyzeMathematics Probability and Statistics.

    Kenny




    Kenny

  • RELEVANCY SCORE 2.49

    DB:2.49:How To Convert Peak Detect.Vi From Ver6i To Ver5.0? as


    Hi I want to capture a peak voltage using ver5.0 but the peak detect.vi in ver6i does not work in ver5.0, what can I do? Can I replace the peak detect.vi with peak detector.vi in ver5.0? Is there any other solution to my problem?Thanks in advance.Mary

  • RELEVANCY SCORE 2.49

    DB:2.49:Locating Time The Signal Crosses A Threshold jk



    Greetings,

    I realized that the peak detection vi only detects the peak locations. Is there a way where i can detect the first location or point which the signal first crosses the threshold instead?

    Thanks.

    DB:2.49:Locating Time The Signal Crosses A Threshold jk


    HI

    Use Transition Measument VI

    You can pass the thresholdusing reference level input and you will get the time for crossing that point from measurement information output of Transition Measument VI.

    Hope this helps

    Regards

    Santosh

  • RELEVANCY SCORE 2.49

    DB:2.49:Problem About Calling A Labview Dll From Vc 6.0 7k


    I design a program in labview to generate two pulses to control the laser.I have built a dll from the vi in labview 7.1 and called the dll from VC 6.0.But The function I called from VC 6.0 didn't work at all.Then I built a dll for the Generate Single Pulse(DAQ-STC).vi,and called it from the VC 6.The calling function doesn't work,either.But the vc could call some easy functions created by labview. the follow is the reports in the debug window:Loaded 'C:\WINNT\system32\ntdll.dll', no matching symbolic information found.Loaded 'F:\soslotos\labviewcode\total\testmutidll\gs.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\version.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\KERNEL32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\lz32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\USER32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\GDI32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\ADVAPI32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\rpcrt4.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\imm32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\lpk.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\usp10.dll', no matching symbolic information found.Loaded 'C:\Program Files\National Instruments\Shared\LabVIEW Run-Time\7.1\lvrt.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\winmm.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\WINSPOOL.DRV', no matching symbolic information found.Loaded 'C:\WINNT\system32\mpr.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\COMDLG32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\SHLWAPI.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\COMCTL32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\SHELL32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\msvcrt.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\OLEAUT32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\OLE32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\wsock32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\ws2_32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\ws2help.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\SETUPAPI.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\USERENV.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\NETAPI32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\secur32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\ntdsapi.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\dnsapi.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\WLDAP32.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\netrap.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\samlib.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\mmdrv.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\MSCTF.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\msimg32.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\clbcatq.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\mydocs.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\SHDOCVW.DLL', no matching symbolic information found.Loaded 'C:\WINNT\system32\msi.dll', no matching symbolic information found.Loaded 'C:\Program Files\National Instruments\Shared\nicont.dll', no matching symbolic information found.Loaded 'C:\WINNT\system32\msvcp60.dll', no matching symbolic information found.



    昨天是今天的昨天明天是今天的明天今天是昨天的明天是明天的昨天

    DB:2.49:Problem About Calling A Labview Dll From Vc 6.0 7k

    The information you provide does not give enough information. The debug log you show only is about all the possible DLLs Visual C is loading on behalve of your application and that they do not contain debug information which is totally normal unless you install checked build (special debug) versions of Windows.The VI you show does not have any front panel control so it will be a void function(void) call only in Visual C. This is of course not a very good idea as you don't even get any error code, which might occur during execution of the VI in the DLL. I would at least chain the error cluster of the VIs together and return the code in the error cluster in a front panel control and then as return value of the function. That way you will see a non-0 value returned to Visual C if any error occurres and looking up the error number in the LabVIEW error handler VI will give you some more hints what might be going wrong.Rolf Kalbermatter



    Rolf KalbermatterCIT Engineering Netherlandsa division of Test Measurement Solutions