Waveform graph with timestamp

I have 5 arrays of data, 4 are data values and 1 is the UTC seconds. I want to use a waveform graph as it smooths the plots so the traces look
more rounded compared to an XY Graph. I have experimented with bundle and build waveform setups but the best I have been able to do is to get the timestamp along the X axis but no data shows up in the graph or all the data shows up as but it looks like the axis is swapped but the timestamp is still at the bottom.
Does anyone know why the waveform graph plots are smoother than the XY Graph plots. If I knew this answer I could use the XYGraph instead.
Thanks
Tim C.
1:30 Seconds ARRRGHHH!!!! I want my popcorn NOW! Isn't there anything faster than a microwave!

I don't notice a difference between an XY Graph and a Waveform Graph if the dt on both are the same and assuming all of the other attributes (interpolation, point style, range, etc.) are the same as shown below. To create a waveform graph and assuming that the dt is constant in your time array, you can do something like the other image. An XY graph is normally used only when the intervals on the x axis are not constant. If you see a difference, you should post your VI (with data in the arrays) so that someone can look at it.
Message Edited by Dennis Knutson on 09-15-2007 09:38 AM
Attachments:
Waveform Graph versus XY Graph.PNG ‏21 KB
Build Waveform.PNG ‏8 KB

Similar Messages

Looking up the values in a waveform graph with a mouse click

Hi,
Does anyone know how to look up the values in a waveform graph with a mouse
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Best regards,
Thijs Boerée

Dear Chad,
I know of the function "bring cursor to center". I also figured out that
when i use a property node of the cursor array of clusters, that i can see
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And to file a product question:
I would like to see the function that with a mouse click a little menu
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Best regards,
And thank you for your help.
Thijs Boer�e
"Chad AE" schreef in bericht
news:[email protected]...
> Dear Thijs,
>
> Thank you for contacting National Instruments.
>
> To address your question, there is no direct VI, command, or property
> node that will allow the cursor snap-to-mouse functionality.
>
> I notice a problem you may be occuring is trying to find where the
> cursor is on the graph. If this is an issue, you can select Bring to
> Center from the Formatting Ring on the Cursor Legend to move the
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>
> Let me know if you have any further questions or if this does not
> resolve your issue, as I would be happy to file a product suggestion
> so that LabVIEW is improved in future versions.
>
> Thanks again and have a great day!
>
> Chad AE
> Applications Engineer - National Instruments

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Hi,
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Hi Garraty,
Excuse me but I have several questions for you.
1)     Have you tried some kind of incremental approach, starting from 1 waveform and increasing towards 36? Do you experience some kind of on/off degeneration between, les’s say, 34 and 35 waveforms?
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Kind Regards
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FiloP
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman

Xy -Graph with timestamp

Hi forum,
i need help again. I have a .csv file from labview where the first row is a timestamp:
08/10/201423:45:53.871
the other rows are floating data.
I would like to read this data and plot it with timestamp on the x-Axis. How i could do this in labview.
Thanks and best
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Attachments:
Capture.PNG ‏22 KB

Hi Martin,
sorry for delay, but next time you should save your VI in LV2011…
See this:
- read in the text file and convert to array of strings
- get columns (instead of rows!) and convert each column depending on its datatype to timestamp and float
- plot data on XY graph
You went wrong on
- the format specifier for SpreadsheetStringToArray
- indexing rows instead of columns
- the whole process of data conversion: after converting to float you convert back to string to finally (trying) to convert back to timestamp…
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Clearing waveform graph with my VI

I know how to clear the waveform graph using feed back array .But my case is different .I attached the VI with which I need help.
Basically I will be reading voltages from Yokogawa 200 which I used random number generator in the program .I need to plot the waveform graph between 3 and 4 mins once the program is started.
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Attachments:
simulated.vi ‏23 KB

You continue to make this much more complicated than it needs to be. You are eligible for the Rube Goldberg thread. You've ignored the modifications I made to your VI in this thread where you asked the same question. Here's a modification with a graph. If you want to ignore suggestions for your problems, maybe you should stop asking for help.Message Edited by Dennis Knutson on 08-14-2007 08:23 AM
Attachments:
simulated_mod2.vi ‏15 KB

Saving "Waveform graph" with cursors, set of different colors, in an image file

Hello:
I'm trying to save to a file, a waveform of a "waveform graph" that has cursors, which have different colors. When opening the file I can see that the waves are plotted defined color, but the grids and cursors are colored black.
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Best Regards

Probably this is happening because you are using the Invoke node Image Export, which captures an image with less information. However, if your application allows, using the Invoke Node Get Image, which captures your control, displays all the colors of your waveform, include cursors and grids colors.
In this link bellow, you can see how use this Invoke Node:
http://digital.ni.com/public.nsf/allkb/5AE4ADCBB65A6D8F86256FBF007A1AC1?OpenDocument
I hope this helped you. Success in your application.
Regards.
Wesley Rocha
Applications Engineer
National Instruments Brazil
www.ni.com/suporte
Wesley Rocha
Application Engineer
National Instruments Brazil
Visite a nossa comunidade em PORTUGUÊS!!!

Dispaying a waveform graph with control of the cursor in the document.

I would like to be able to control the cursor when I save my waveform graph in html. I'm currently saving the graph through the report vi's

I am not sure I understand your question. Do you want to simply control where the cursor is on the picture you are appending to the html report. If so then when you use the Append Control Image to Report VI it basically takes a snap shot at that moment and displays it. Therefore you just need to place the cursor where you wnat it before you add the image.
To programttically control the cursor you will need to use property nodes of the Waveform Graph. A good start would be the property cursor>>cursor position>>all elements.

Display saved lvm file to graph with timestamp

Hi,
I'm having headache displaying my data with proper time-stamping. There are so many methods to save data. here I've decided to save it as a text delimited file format as lvm. a segment of my vi screen shot is attached. I want to use this way instead of other methods is the flexibilty it offers. I will be able to add on more data to store as I develop the vi. (So I'm storing data from DAQ assistant and my calculated values.) I attached a the screenshot of the file I read too.
I would like to use another vi to open this file and plot it to a graph/chart to display as a trending of the data acquired. Can someone pls advise mi on what is a better way for mi to do it?
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Poh
Solved!
Go to Solution.
Attachments:
datalogging vi.JPG ‏82 KB
logged data.JPG ‏76 KB

Hi Krisna,
Sorry for the late reply, I was rushing to complete my project, wasn't able to reply.
Yes, I managed to solve it. Anyway I used such high rate in the DAQ assistant is to allow continous mode acqusition & use a software filter instead of hardware filter. however writing to file in this way - writing string into .lvm, max is 10 samples/sec. unless I use tdm (I'll then log everything).
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This extracted (could be seen as a bunch of numbers in the lvm file) and and converted back to timestamp type and wired to build waveform block, providing the start-time of the waveform.
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Attachments:
display graph.JPG ‏39 KB
data.JPG ‏171 KB

Real time waveform graph in while loop

Hi
I have a VI which includes a subVI that reads data from an oscilloscope and presents the output in the form of a cluster made up of the initial time t(0), a time interval delta t and an array of voltage readings.
This cluster can then be wired to a waveform graph in the usual way. All of this is situated within a while loop in my VI and on each iteration of the loop I obtain a waveform graph of the voltage readings starting at the same time t(0) and ending at the same time t. However I want my graph to begin at a time t(0) when I set my VI running and then continuously acquire and build up the data on each iteration of the while loop so after my VI has finished executing I have a complete graph of all the voltage readings acquired after the set number of iterations of the loop. I know on the Express X-Y Graph VI you can double-click the node and deselect the box that says 'clear data on each call' - if I could do this in my case that would be great but I can't use an x-y graph because I have an array of y-values to plot on each iteration.
If anyone can help me out it would be much appreciated - I'm sure there must be an easy solution to this but I'm going out of my mind trying to find out what it is!
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As usual, you have several options.
You can use an XY Graph by generating the X values yourself. This will ensure that you place the data exactly where you want it on the X axis. This is fast, but does involve a memory cost.
You can use a Waveform Graph with a waveform input instead of the cluster you are using. Use the Build Waveform primitive instead of the bundler to make your waveform. Set the t0 values to the appropriate values (negatives do work, as do small numbers - time is in seconds, use the To Time Stamp primitive to convert from DBL to timestamp). Finally, you need to set the Waveform Graph to use the t0 values. Pop up on the Waveform Graph and make sure Ignore Time Stamp is not checked. Depending on your version of LabVIEW, you may have to pop up on the graph or the axis. When you unselect Ignore Time Stamp, you will probably want to reformat the X-axis again. The Waveform Graph clears data at each iteration, so you will need to replot all your data each time. Just create an array of waveforms and keep adding to it. The t0s will put the waveforms in the right places. Yes, this may cause memory problems.
Finally, you can use the Waveform Chart, which does have memory. Create the waveforms like you did for the Waveform Graph and send them to the chart. It will remember what was sent to it from run to run. Make sure you set the Chart History Length (pop up on chart and select Chart History Length...) to long enough to hold your entire data. You can use a property node to get the data back at the end, if you need to.
Good luck!
This account is no longer active. Contact ShadesOfGray for current posts and information.

Converting data in waveform graph to an ASCII file

We are using a Labview program to acquire rapid voltage data, however due to specifications on the board we are employing a voltage divider factor that can be changed in the program, as well as sensing the polarity and correcting it so that the voltage is always positive. This data is saved in raw form to a bin file. To view this data, we have another program that has inputs for the scan rate and voltage divider factor, and then it reads the raw binary file and generates voltage vs. time data directly into a waveform graph. No one here actually wrote this entire program, it is my understanding that NI originally helped to develop the program and no one in my group fully understands the intricacies.
What we would like to do is obtain data in 2-column ASCII format from the waveform graph directly (voltage vs. time) in some way. Is this possible, and if so how can it be done? The program is currently run off of Labview 4.1, however we also have Labview 7.0 on another computer and can copy the program and bin files if necessary.
Any help is greatly appreciated.

I'm having some trouble because the data is not technically in a waveform (brownish-red colored wire). The program builds a waveform *graph* (cluster data with pink wire) using the bundle function, where the top input is a dbl x0 that is generated from (1/scan rate) multiplied by the first scan number. The middle input is delta(t), which is just (1/scan rate), and the bottom input is a 2D array of two columns of voltage data, one is voltage and the second is a voltage from another channel that I don't need, and I can't figure out how the 2D array is generated because it looks like it should only be 1D (it suddenly becomes 2D after leaving a for loop). This creates a waveform graph with time vs. the 2 sets of voltage data.
So you'd think you could just build a waveform with the same data, but the "build waveform" function wants a t0 with a timestamp format and a 1D array for the 'Y' input, and I also can't just convert the cluster data for the waveform graph to an array using the 'cluster to array' function as it gives me a data mismatch.
Does anyone know how to remove the first column or row of a 2D array and create a 1D array? Also, how can I input a timestamped t0 if it needs to be on the order of <1 ms, since milliseconds are crucial here? Is there any way to make a waveform with a decimal t0 instead of this ridiculous timestamp?
Thanks again for any help.
Message Edited by chemengr on 06-19-2006 09:23 AM

(Multi^n)plot Waveform Graphs

I'm using LabView 8.2 and I need a waveform graph with twenty waveforms overlayed onto it (actually two waveforms taken ten times each, if that matters--but no, I can't just average them). Using Build Array to make a standard multiplot with the Express Waveform Graph doesn't work, however, apparently because the express VI can only handle two waveforms at once.
Suggestions?
Solved!
Go to Solution.

Hi DJDDA,
when the Express vi doesn't work don't use it!
Just use the way that is shown in the context help of a waveform graph indicator: simply build an array of plots...
Message Edited by GerdW on 06-20-2009 05:59 PM
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome
Attachments:
20plots_lv71.vi ‏27 KB

Plot excel data onto X-Y graph with time stamp

Dear all, I have the same set of data but it is saved in excel format instead of text file now. However i think the column data are separated by tab, i have tried to write some codes but it dont seem to plot out the graph properly. I have no problem ploting out data in text file but not this excel file. Can anyone help out to plot this graph with timestamp?
Attachments:
test4.txt ‏1 KB

I still don't understand your comment 'I have no problem ploting out data in text file'. The Read From Spreadsheet by default uses a tab separator so you should have no problem reading the file. Post the code you have already written so someone can see where your problem is.

Multiplot graph with missing values fills them with zero instead of NaN

I have a waveform graph with multiple arrays (2D) which has different numbers of points in each array. LabVIEW finds the array with the most points and then plots all arrays with that many points. It assigns the missing points a value of zero and displays those zero values. This means arrays with fewer points than the maximum will have values of zero appear in their plots. This can be avoided by filling in missing points with NaN. I am acquiring data in a loop and displaying it which requires continuous determination of the number of actual points and filling in of missing points with NaN. Not difficult, but this could be avoided if LabVIEW would fill missing points with NaN instead of with zero. Any way to have this happen automatically ?
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Attachments:
Graph MultiPlot Missing Data.vi ‏18 KB

You can also consider using an XY graph so you don't have to do additional data manipulation. See attached for comparison.
Attachments:
Graph MultiPlot Missing Data mod.vi ‏22 KB

Change waveform graph plot order

I am using waveform graph with 2D input dat to create two plots, each with its own y-axis, but a common x-axis. Plot 0 is always on top of Plot 1. Is there a way to have Plot 1 on top of (in front of) Plot 0?
--Ryan
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You would only need to reorder the array that's fed to the graph. You would not need to change the original dataset. See attached for a sample.
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Attachments:
reorder graphs.vi ‏18 KB

Waveform graph - Number of major ticks on x scale

Hello all!
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Regards,
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There is a Marker Spacing property to which you can write a custom array. This sets the scale Marker spacing to arbitrary. See attached vi as an example. Work still needed to make it look acceptable regarding labels.
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Waveform graph with timestamp

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