Cluster build waveform t0 timestamp waveform graph

Hello
I would expect both examples in the picture to behave the same way. Why
aren't the signals in the upper example shifted to the right?
Regards
Stefan
Attachments:
problem.png ‏24 KB

Right click on the graph and see if you have 'Ignore Time Stamp' checked?

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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

How to create an intensity waveform graph cluster with t_0 and dt ?

Hi all,
I would like to know whether it is possible to create an intensity waveform like you can do with a 1-d waveform (with "build waveform") so that you get a cluster with the waveform array, the t_0, the dtand the attributes.
If not I would like to know the following: I use references to cluster typedefs to update my controls and indicaters on the front panel. Now if I use a property node for the intensity graph to set the offset and multiplier on the x-scale, the x-scale on the graphs on the sub-VI work perfectly, however not on the real front panel, probably since these get updated through a reference. Does anyone have a clue how to fix this?
Regards, Pieter

You are only writing the "value" of the type definition via the property node. This does not include properties such as offset and multiplier.
On a sidenote, you are using way too much code for most operations.
For example, the to-I32 can be placed on the cluster, so only one instance is needed.
Also property nodes are resizeable, so only one instance is needed.
There are also Rube Goldberg constructs, such as ">0 *AND* TRUE", which is the same as a simple ">0"
Overall, you are really fragmenting memory by constantly building and then resizing arrays to keep them at a max size of 2880. This can cause performance problems due to the constant need of reallocations. It might be better to use fixed size arrays and do things "in place".
Message Edited by altenbach on 03-19-2009 09:57 AM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
OneIsEnough.png ‏8 KB
CombineProperties.png ‏3 KB

'build waveform' in cluster-constant not possible?

I would like to read a 2d-array of a cluster from file that contains - beside 4 clusters - a waveform.
As far as I understand, you have to determine the byte-stream-type for the "read-file" operation.
In order to do so I tried to generate a 2d-array-constant that contains the cluster mentioned above with all values as empty constants.
But soemhow it doesnt seem to work for "build waveforms". I am not able to put the waveform inside the cluster!?
Any ideas so far?
Thanks in advance
Thomas

I'm a lttle confused. You can put a waveform datatype inside a cluster and put that cluster inside an array and make that array multi-dimensional. This is all easily done on the front panel. Putting a function like "Build Waveform" inside a cluster doesn't work any more than trying to put an arithmetic function inside a cluster. Clusters hold valid datatypes, not functions. If I've misunderstood your problem, could you explain a little more?

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!
Many thanks,
Bex.

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!
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How to convert cluster to waveform?

I'm having trouble building a waveform properly. I have a relativeX, an Xincrement, and a 1D array of data (what is returned from a 5114 scope). But the 'build waveform' function wants t0 to be a timestamp. This isn't what I want....
I don't mind just using the cluster for showing it on a waveform graph because it works and it's not a problem. However, there are a lot of waveform functions for writing waveforms to files that I would like to take advantage of....how can I do this?
thanks,
-Z

I think I am with you and the answer is probably not. You can work with both datatypes but if you want to use waveform datatype then there is a little more work to get the graphs looking the same with a negative x0
Let me know you labview version and I will post the above vi for you to study.
David
Message Edited by David Crawford on 10-25-2006 09:20 AM
Attachments:
Waveform Graph - Cluster or Waveform Data Type.jpg ‏24 KB

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

Y scale flip in waveform graph when using property node.

I'm having problem with property node. I'm trying to build a stackable scope with Waveform Graph And dynamically change the number of plots. It is working. But The Y scale is flipping. The minimum goes on the upper part and the minimum scale goes down. when I change it appearance it's not very fast. It take about 1 or 2 second on my computer.
The way it is build actually is:
Cluster_1 is containing 8 clusters. And each of the 8 clusters are containing a Waveform Graph. By reference I change the property of each Waveform to make visible or not each of the Waveforms.
First I would like to solve the scale problem and second accelerate the redrawing of my scope.
Maybe there is an other way t
o do what I need.
Thanks.
Nitrof
Attachments:
MultiScopeExample.llb ‏192 KB

Wow, you have a neat program! The problem with your y axis flipping is because the last four charts in the cluster were programmed with a flipped axis. I relabeled the charts and it worked correctly.
From what I could tell with your code, you do not need the sequence structures. The one inside of the even actually runs the same code twice. Remove this duplication and you should see improvement. Also clusters are slow, so you should not expect it to blink back with additional coding. Use defer panel updates to get that behavior. I incorporated these changes and attached the program.
Jeremy Braden
National Instruments
Attachments:
MultiScopeExample.vi ‏163 KB

Can't create constant for cluster with waveform inside it..

I have an indicator cluster that contains a timestamp, string, three booleans, two doubles, and a graph using a 1D array of waveform datatype. When I include the waveform graph inside the cluster, I can't right click the control terminal and create a constant. Is it possible to create a constant for the waveform datatype??
Attachments:
front_panel_cluster_with_waveform_control.ctl ‏24 KB

There is an "Analyze" palette that has numerous analysis functions that operate on 2D arrays. It is located next to the "Waveform" palette.
None of the graphs or charts have constant equivalents, so if you use a 2D graph in the cluster you still can't create a constant for the cluster. Since I not sure what your reason is for using a graph in a cluster, I am making this next comment ignorant of your use case. With that said... In general graphs are very useful for viewing data. They are not recommended for data transferring as they carry a much larger footprint than a waveform datatype or 2D array. If you are frequently using this typedef cluster in your VIs, especially in VIs that are not part of your user interface, you may want to consider not
using a graph in the cluster. Or you could have 2 versions of the cluster -- one for user interface display purposes (with a graph) and one for programming purposes (no graph).
Deborah

How can I get the cursor value from a waveform graph

Is there a way to get the value of cursor position on the waveform graph so mathematical calculations be performed on those values. We can see the value in cursor legend, but can we extract those values for future calculations in the block diagram somehow.

Right-click on the waveform graph icon. Select Create>Property Node>Cursor>Cursor Position. That spits out a a xy cluster for the current cursor position.
If you have more than one cursor, you can either set up a loop and set the Active Cursor property node (right click the property node and select "Change to Write") or you can pull everything you ever wanted to know about every cursor with the Cursor List property node.

I would like to see the time in a waveform graph (real-time)

i need the x-axis of the waveform graph to show real time (from the computer clock). I have made a program with all the example. He read and log data when the chosen time has elapsed. the program work's well...but i dont't know why the x-axis blink every time he draw a point
i can see two x-axis in the same time.
i give you a picture of one of a part of my program, i hope someone can help me
Attachments:
my_software.JPG ‏128 KB

Hi,
I tried to reproduce what you were getting by building a simple VI but I havent had much luck (I have attached the VI).
Could you post your code so that I can take a look at it?
Feroz P
National Instruments
Attachments:
Graph.vi ‏39 KB

Bug in Digital Waveform Graph X-Axis

Hello,
I am making separate queried to a database to retrieve analog and digital data over the same time period. The data were logged at 2 second intervals. I have verified that both result sets return the same number of values with the same t0 and dt. I then plot the analog values on an XY Graph and the digital values on a Digital Waveform Graph. I then use property nodes to sync the two graphs (left and right plot bounds, XScale.Range, and Cursor Position.X). After doing this, I can see that the datasets do not line up between the two graphs. The data on the Digital Waveform graph ends several seconds sooner than the analog data. The x scales of the graphs appear to match but the plots don't align in time.
Has anyone else observed this behavior? Is there any work-around?
Thank you,
Peter

There is a much simpler way to synchronize these charts. Just use a stacked chart.
If you use a bundle function you can take two signals (almost data type) and wire them into a Waveform Chart together.
Then on the front panel right click on the chart and select Stack Plots
Since you only have 1 X axis now they are instrincly synched and will always write valules at the same time and update the UI together. You can skip all of the scale synching....
Since the data you are working with has lincked time stamps, the data will need to be matched, (make sure the samples are anyched and each itteration both would have the same number of samples.
The last allternative would be to strip the time stamp off of your data then build a new data structure, with the digital data, analog data and 1 set of matched time stamps. You can then plot this on an XY chart using the time stamp for the X axis for both of your other plots. Let me know if you have other questions.

How plotting on a digital waveform graph the bit transition in function of the time

Hi everyone,
I am using LabView 6.1 on a Windows XP computer. I am to plot output bits sequences on a digital waveform graph just before sending the information to a board.
So far I can see the transitions for my 16-bit port (16 plots) but the width of a pulse is always identical, no matter what times I enter. I wired my 1-D array timestamps to the property node Xscale.MarkerVals[] of my digital waveform graph... but it doesn't seem to affect my plotting...
Thanks in advance for any help concerning this problem.
Jonathan Sabah

Well here is piece of my VI with the necessary sub VI.
I also want to hide/unhide plots... I have found how to hide.. but cannot figure out how to unhide.
Any help please ?
Thanks again
Jonathan
Attachments:
Exemple.vi ‏58 KB
Setup_DIO64_for_Output_1.0.vi ‏111 KB

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
click but... without the cursor legend on, if i press in the waveform graph
nothing happens, i must search my cursors and only then i can see the values
of my signal data?! Isn't there any other way?
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
that some values change when i move the cursor (i can see the X and Y scale
value change of the graph and also the values of the mouse pointer (in
points due to screen resolution)) But in this cluster i can't set the mouse
position. I allready made a VI where i can see the bounds of my
waveformgraph and I have the Xscale (min and max) and the Yscale (min and
max), with a linear fit i can translate my mouse position to X an Y scale
values and when i click on my waveform graph the cursor go's to that
position (property node of the cursor position), only disadvantage is that i
only have the bounds of my plot area and not the position, i do have the
position of my waveform graph but the plot area isn't allways in the center,
if i could extract the position of the plot area i may find a solution to
solve this problem.
And to file a product question:
I would like to see the function that with a mouse click a little menu
appears and that there are options to for example set a marker on that data
and when you right click on it, that there are options to remove it or to
add comment, a 2D array could make a list of the different channels with
it's markers (time stamps and comments).
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
> cursor to the center of the graph.
>
> 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

Append data to a waveform graph

I am using the Acquire N - Multi-Digital Trig to acquire a series of data. I wish to store the data acquired, by saving them into a file (Export Waveforms To Spreadsheet File) however, the waveform graph data are not appended. I have tried to see the example provided for appending data to a waveform graph (example.zip) on this webpage but I wasn't able to apply the principle to my application. (I have even tried the Append Waveforms.vi function but I cannot connect it to the waveform graph data).
I will appreciate it if I can have any suggestions on how to append the waveform graph data, so as to store them in a file.
Thank you

There is an Append Waveforms.vi that you can use for this. It's located in the Functions>>Waveform>>Waveform Operations palette. That will append two waveforms, which is different from just an array. If you only want to append arrays, you can use the Build Array function to concatenate two arrays.
J.R. Allen

Cluster build waveform t0 timestamp waveform graph

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