Configure x axes waveform chart

how should I configure the x-axes of waveform chart as I wanted it to be eff vs Iout.
Currently the setting I manage to generated is eff+Ioutvs time(bundle the signal of eff n Iout).
another would be Eff vs Ioutbut this only possible if the signal indexed into array.
But my requirement is to view the signal immediately rather than at the end when the process finished.
below is my attempt to generate eff vs Iout.(Which of course unable.)
Message Edited by 3den on 05-09-2007 08:41 PM

It's so much easier to just attach an image to your post by clicking on the browse button next to the attachment field below this message body.
It sounds like you should be using an XY Graph. The waveform chart will only plot a y value versus time. Use the Express XY Graph to plot as data is acquired or use the shipping example called XY Chart.

Similar Messages

Display Data on waveform chart or XY graph over a long period of time

Display Data on waveform chart or XY graph over a long period of time
Can anyone help?
I am acquiring data from an Ni DAQ card with the following parameters - sample rate = 12800, number of samples = 4096. I want to extract order information so as to track changes in the amplitudes of certain frequency harmonics. So I use the sound and vibration toolkit to extract this information as shown in the attached Vi. I will like to plot the resulting amplitudes against real-time starting at the time the Vi was run. I really want the display to show these changes over long periods (eg. days, months and even years).
Problem.
I have tried to plot the Y component of the resulting magnitude for a given order on a waveform chart. My choice of the waveform chart is because I also want to display alarm limits (using the mask and limit vi) (I can't have these lines displayed on an XY graph plot). I tried adjusting the scale offset using the property node and setting the offset to current time. However, the display on the X-axis can only show a span of 2 minutes as will be seen when you run the attached vi. I want the time display on the x-axis to be over a period of days, months and even years. Is there a way to set the maximum scale on the x-axis to be say a year or so in future.
I really want the display to be like the one in in the second attachment.
Attached is a sample VI created using an Ni USB 9234 DAQ card. Any card will do but I am only getting the signal from one channel for this example
I will appreciate any help that can be given to me.
Thanks
Attachments:
Real-Time Graph Display.vi ‏170 KB
Sampe screen1.doc ‏37 KB

Long term testing can be tricky- and we'l get into that later. Lets start with the basics that you have wrong.
The vi as you have constructed it has only one memory element, the chart history length (default is 1024.)
You can change the number of points the Chart will remember by Right-clicking the chart an select Chart History Length from the menu.
But for a long term test - and one where you want to REMEMBER the first value you need a memeory element that is independant of the application. Your PC WILL loose power or need to be rebooted eventually. Heck it might even need to be replaced! you really need to store your data in a file. Preferablly in a file that is backed-up on a regular basis so you don't lose every point of data if the PC dies. It realy hurts when you have to restart a 2yr test because you've lost the 18months of data you collected.
For an application like this I would seperate my "collection" and "Evaluation" operations.
Have one vi that takes the reading and writes it to a file at a configurable rate You may want 1reading per minute for seveal days then 1 per hour for a few weeks- then maybe only once or twice a week for the next couple of years since you are looking for LONG TERM stability. having too much data to evaluate can take a lot of digging to find the few things that interest you (but always take more that you think you need)
Have another utility that COPIES the files, reads them and displays the data you are interested in that day. The data you want to look at won't change over time HOWEVER, you WILL want to analize it in different ways depending on what the data trends look like. Having seperate routines for collection and display allows you to update the display style and analisys without even stopping the collection vi (much less editing the vi)
Jeff

Question from waveform chart

Hi,
this must be a simple question, but I want to "fix" time axis "between 0sec and 10sec" although the running time of my vi is more than 100 sec, i.e., I want to reset the waveform chart every 10sec. Please help me out thanks.

Maybe this is what you want : just configure your waveform chart to "scope chart" (right click on chart then "advanced" and "update mode")
See attached picture.
regards,
xavier
Attachments:
Exemple.jpg ‏90 KB

Waveform chart to looking like this excel format

hello,
i am using the DAQ assistant.
i configured it to have 9 channels of data.
can someone guy me into exporting the data to look like this excel file?
how can i take the data from the waveform chart and input it into the RAWDATA STRING so that it look like the format in the excel sheet?
thanks!
Attachments:
TCs.vi ‏108 KB
082714.001.csv ‏139 KB

No need to delete old posts. It may help someone in the future and if not, it will fall off the main pages and dwell forever in land that time forgot... Or the NSA will grab it.
Using LabVIEW: 7.1.1, 8.5.1 & 2013

How to set waveform chart to start data since beginning of run

Solved!
Go to Solution.
Attachments:
TCs.vi ‏106 KB

You need to check the update mode of your chart.
Strip Chart—Shows running data continuously scrolling from left to right across the chart with old data on the left and new data on the right. A strip chart is similar to a paper tape strip chart recorder. Strip Chart is the default update mode.
Scope Chart—Shows one item of data, such as a pulse or wave, scrolling partway across the chart from left to right. For each new value, the chart plots the value to the right of the last value. When the plot reaches the right border of the plotting area, LabVIEW erases the plot and begins plotting again from the left border. The retracing display of a scope chart is similar to an oscilloscope.
Sweep Chart—Works similarly to a scope chart except it shows the old data on the right and the new data on the left separated by a vertical line. LabVIEW does not erase the plot in a sweep chart when the plot reaches the right border of the plotting area. A sweep chart is similar to an EKG display.
From the help menu:
The waveform chart maintains a history of data, or buffer, from previous updates. Right-click the chart and select Chart History Length from the shortcut menu to configure the buffer. The default chart history length for a waveform chart is 1,024 data points. The frequency at which you send data to the chart determines how often the chart redraws.
Attachments:
resp2.jpg ‏36 KB

Waveform chart number of clusters

I am in the process of modifying a VI worked up by one of my coworkers. My setup has 4 waveforms coming into a "Bundle" block and then the resulting cluster going to a waveform chart. My coworker's VI was working with 8 waveforms. When I copied his waveform chart into my VI and tried to connect the bundle of now 4 waveforms to that waveform chart, it gives me the error "You have connected 2 clusters with different contents. Clusters (unnamed), a cluster of 4 elements, conflicts with cluster waveform chart, a cluster of 8 elements." How do I change the number of elements that the waveform chart is expecting? I've been poking around at it for a couple hours and havn't found a solution. I tried creating a new chart but can't figure out how to make it accept clusters instead of the default double precision input. Let me know if you need more description. Thanks.

I don't think it's possible to send in a cluster of waveforms to a waveform chart at all, regardless of how many waveforms are in the cluster. To send in multiple waveforms into a waveform chart, build them into an array of waveforms.
You do need to bundle scalar data into a cluster when sending multiple single-point signals into a waveform chart so that the waveform chart doesn't confuse an array of separate signals with an array of values from one individual signal.
Charts automatically change to the data type that is input into them. By default, they're scalar doubles. If you wire a cluster of scalars into them, then they change into scalars. My guess is you had a waveform chart configured to be a cluster of scalars, and then you were trying to wire an cluster of waveforms into it.
In any case, always refer to the example Charts.vi in the Example Finder (Help >> Find Examples from LabVIEW) for examples of properly sending in data to waveform charts. For waveform graphs, the example is called Waveform Graph.vi, and for XY graphs the example is called XY Chart.vi. Hope this helps!
Jarrod S.
National Instruments

How to update the absolute time value in waveform chart for labview 6i?

Hey there,
I'm developing a control system using labview 6i on win 2000 os.I'm receiving the sensor data every minute and i want to display the data on a waveform chart with absolute time scale on x-axes. I'm using the property nodes for the offset, multiplier and maximum values putting them outside the while loop and giving them input using get date/time in seconds function. the problem is that the time doesn't gets updated w/ refernce to the computer time and after a certain period the time shown on x-axes lags by several hours. any advise?

Posting an example ussually help us nail these types of issues fast.
I am therfore forced to guess.
Do you have your code written such that the scale operations occur before the loop?
The next thing I have to suspect (not being able to see your code) is if your dt is correct. If your dt is larger than what the chart is set for, then the time will fall behind.
I have included an image showing how the chart can be used to show multiple sample rate plots such that the t0 of the readings are used to control how the readings are displayed. This example uses waveform data types (I believe they were available back in 6i). It should serve as a guide to do what you want.
I suggest you start by recreating the demo and play with it until you have what
you will need in your app.
The beauty of this method is it lets you use the chart to plot signals acquired at different frequecies and plot them all together.
reply to this answer if you have questions,
Ben
Ben Rayner
Certified LabVIEW Developer
www.DSAutomation.com
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction
Attachments:
Wform_demo.bmp ‏427 KB

Waveform chart x-axis in time (secs)

Ok here's what I'm trying to achieve (unsuccessfully at the moment). I've got a 2D array of data collected from a sensor. Each column in the array corresponds to one of the sensor's axes. I want to display 3 columns of data on a waveform chart with the magnitude of the data as the Y axis and time as the Z axis.
Here's the tricky bit. I have no timestamp with the data. However, I'm taking the first element of data in each column as being T (time) = 0. The sampling rate of the sensor is 100Hz so => dt = 0.01. So each data element in each column (sample) is separated by 0.01 seconds. Therefore by knowing the number of samples in a column of the array, I can get the end time. E.G. 1000 elements in one column of the array => end time, T = 1000 * 0.01 = 10 seconds.
So in the above example the chart's time axis should go from t = 00:00:00 to t = 00:00:10. However I'm not gettin anything like this in my chart. I did up a quick vi showing what I'm currently doin.
Any tips?
Attachments:
2D waveform chart.vi ‏32 KB

I've re-attached my example vi with a minor adjustment highlighting the problem. Each column of the array now contains 2000 elements which exceeds the deafult chart history buffer length value of 1024. This causes problems with the time display on the chart. I could of course change the chart history buffer length manually by right clicking etc. but would need to do it in real time in my actual vi as I won't know the size of the array until execution.
Is that clearer?
Running the vi now should show you, the time starts at 00:00:09 instead of 00:00:00. I understand why but not how to fix it...

The waveform chart in the tab control

Hi,
I'd like to change the plot number and the plot name of a waveform chart in a tab control.
First of all, it works fine without a tab control, but I have many charts(such as temperature, pressure, voltage...) so that I put each chart into the pages of a tab control.
Error 1077 happened when I "add" the plot number and change the plot name.
The following is a sample I made to describe this problem.
Let's begin if the number is 20, so there are 20 plots in that chart in page 2.
t
Do not turn on the switch, change C to 3, minus N to 18, and run it and it can be seen that the tab control will switch to page1.
Switch to page 2, and the plot names are updated but left some relic.
Add N to 22, change C to 2, and run it again.
Error 1077 happened! Switch to page 2, and the plot number is still 20, and the plot names are updated to 20.
Run it again, and it works fine!
It is very tricky for me.
If I switch to the page 2 first and run the program, it works fine too.
(That is, if the switch is turn on, then the program works fine.)
The LabVIEW version of mine is 2011.
I'm not sure I missed or misunderstanded something about this problem.
Does someone can give me some suggestion? Thanks a lot
Solved!
Go to Solution.

Hi, Bob_Schor,
I'm sorry my poor expression confused you.
All I want is to demonstrate that the chart in the 'hidden' page of the tab control results in the error when the user tried to add plot number and change the plot name.
To make a scenario more specific, there is two pages in a tab control, one is for setting, the other is for the plotting.
When the user change the channel configuration, the chart is going to change correspondingly.
If I'd like to change the plot number and plot names, there is possiby a problem when staying in the setting page.
I hope I do not mislead you to the wrong direction
You're right I should make the parameters more clear to facilitate reader understand my purpose easily.
Switch True means switch to the chart page before the modification of the chart, and return to the first page after the modification. Switch False means stay in the first page while the chart is modified.
C is used to make the plot name different among each execution. If the plot names of the chart in the previous execution are [101, 102, 103, 104, 105], and I'd like to decrease the plot names to three items [101, 102, 103], but in the case of the false switch, it will be [101, 102, 103, 104, 105], it is hard to tell if it is really updated. I can change C to 2, and the plot names in this execution will be [201, 202, 203, 104, 105], it could be shown it is updated indeed but left some unexpected plot names[104, 105](I call it relic...).
N is just the plot number the user can increase or decrease it.
I'm afraid of being the guy you mentioned...
Like my original post, I probably have several charts to show their results(temperature, pressure, voltage...) so that I make a tab control of 6 pages, and put a chart in each page. The user can also determine the channel numbers of each kind of measurement before the acquisition. I didn't think too much about it(actually now I still have this direct simple idea only...), what would you do if you have to show these data? Very thanks to your reply

Waveform Charts

Hello,
I use the AI Read VI (waveform) to read data from a buffered data
acquisition, do some process and then display the waveform in Waveform
Chart. The problem is that although I use a property node to initially set
the x-axes scale (offset=0 and multiplier), when the acquisition begins the
x-scale start from 3418:XX:XX. ( the format of the x-scale is
Decimal::Relative Time(seconds). I would like the time axis to begin at time
0 at the beginning of the acquisition.
I do not understand the reason this offset occures.
Can anyone help me?
Thanks in advance,
M.

Thanks for the tip. It worked just fine.
M.
"Greg McKaskle" wrote in message
news:[email protected]..
> ...The problem is that although I use a property node to initially set
> > the x-axes scale (offset=0 and multiplier), when the acquisition begins
the
> > x-scale start from 3418:XX:XX. ( the format of the x-scale is
> > Decimal::Relative Time(seconds). I would like the time axis to begin at
time
> > 0 at the beginning of the acquisition.
> > I do not understand the reason this offset occures.
> > Can anyone help me?
> >
>
>
> The problem here is that the time being sent to the chart is an absolute
time,
> and the display is a delta, a relative time. You have two pretty easy
solutions.
> One is to extract the time of the f
irst sample and subtract its t0 from
each
> waveform including the first one. This will send the delta between
waveforms
> and the first acquisition.
>
> Another solution is to set the offset not to zero, but to the negative
> of the
> first timestamp. This will tell the chart to subtract this value from
each
> waveform as they are being plotted.
>
> Greg McKaskle

Slow response LV7.0 and waveform charts

I have noticed a couple of issues with a waveform chart (when actually plotting a waveform).
1. Sometimes when I right-click on the chart to format a axes it may take up to 5 minutes to display the window with the chart format controls. During this time task manager says the application is not responding.
2. When plotting anything with size (I am trying to plot 5 minutes of data at 512 samples/sec) the program slows to a crawl. If I plot a double data (take the Y data from the waveform) it works great. Why is there so much overhead with a waveform chart? Anyway to fix this?
3. Unrelated to a waveform chart but related to item 1. Sometimes when I try to save my VI (~470 kb) it goes into limbo and may take minutes
. Again the task manager says it is "not responding". This seems to be a theme with LV 7.0. Has anyone else run into this problem?

> 1. Sometimes when I right-click on the chart to format a axes it may
> take up to 5 minutes to display the window with the chart format
> controls. During this time task manager says the application is not
> responding.
>
> 2. When plotting anything with size (I am trying to plot 5 minutes of
> data at 512 samples/sec) the program slows to a crawl. If I plot a
> double data (take the Y data from the waveform) it works great. Why
> is there so much overhead with a waveform chart? Anyway to fix this?
>
> 3. Unrelated to a waveform chart but related to item 1. Sometimes
> when I try to save my VI (~470 kb) it goes into limbo and may take
> minutes. Again the task manager says it is "not responding". This
> seems to be a theme with LV 7.0. Has
anyone else run into this
> problem?
Without looking at the waveform chart, it is hard to say. Things like
autoscale will slow teh chart down a bit as it then needs to traverse
more data looking for min/max. And when the scales do need to change a
bit, all the data needs to be replotted, not just the new stuff.
Other things that slow down a chart are to make its background
transparent, and to make it overlapped. Finally, full screen updates on
a big monitor mean lots of data needs to be moved around to draw lines
and rectangles, and that either comes down to the CPU or video card.
If you have more questions, or a VI to look at, post again.
Greg McKaskle

Waveform charts slowed down control system while loop

Hi
In my application, I have control system which i acquire data, process and output the result. I placed some waveform charts in the while loop where i acquire data, process and output. This made while loop to miss data points( late). Is this because waveform charts store data as time passes?

Waveform charts store data in a history buffer of configurable size. You can change it to a smaller number.
What is the size of the history buffer?
How many charts are you updating in your loop?
What else is happening in your loop?
How are you updating them (wire, local variable, value property, etc).
How fast is your loop rate?
Are your plots simple (thin lines) or fancy (e.g. large dots and thick lines)?
Is autoscaling on or off?
Are the charts set to "synchronous display" by accident?
How many traces are on your chart?
What is your LabVIEW version?
What is your OS?
Do you have overlapping elements on the front panel?
Could you attach a simplified version of your code so we have a better idea what you're actually doing?
LabVIEW Champion . Do more with less code and in less time .

How can i display Waveform chart in a subpanel using Vi templates.

Hi All
I am new to Labview hence need some help. I am trying to develop an application which reads some data from a Wireless Sensor Network (WSN). The WSN consists of base station connected to the USB port which recieves data from other sensor nodes. The data comes in a certain format. Node name, temperature reading, humidity reading etc. I want to read the data from the serial port and based on the Node name, i want to display the information for each node in s separate window or subpanel etc. So if a new node is detected then a new window is created for that node. Since all the nodes have the same sensors on board i only need a one template. I can read the data using the serial port, parse the data to detect which node it is and also what the sensor readings are. I have created a template VI for the sensor node. I am having problems in displaying the template VIs in a subpanel. I can succesfully display a Waveform graph in the subpanel but i am having problems in displaying a waveform chart in the subpanel. I can see the actual waveform chart in the subpanel, but i cannot see the plot. Would be greatful if someone could point out what i am doing wrong here.
Many Thanks
Raza
Solved!
Go to Solution.
Attachments:
template_graph.vi ‏16 KB
graph_template.vit ‏11 KB

Hi All
I think i have solved the problem. It seems like i was running the Vi in a loop. I have taken the Run Vi outside the while lopp and this works fine. Also i need to close the reference at the end.
Raza

How can i print out the waveform chart?

hello everybody,
how can i print out the "waveform chart". can i do it just push the button. ( example; stop button is stop the program etc..)
i checked the NI examples but i can't understand. i'm new to the Labview.
pls help me.
i added the my program
look forward your reply
regards from turkey...
Message Edited by hknmkt on 05-29-2008 04:15 AM
Attachments:
29.05.2008_11.vi ‏37 KB

hi jim,
i tried the program but it's not running. When i run the program, it's print out without run the program
i added the printed file.
look forward your reply
hakan
Attachments:
error8.JPG ‏8 KB

How can I display more than 1 loop iteraction in a waveform chart?

Using DAQmx, I am inputting a signal at a rate of 10k with 1k samples inside a while loop. I want the first 3 seconds of data to display on a waveform chart without having to change the rate or number of samples. Is there a way to stop the waveform chart from clearing after every loop iteration so that I can display more than 0.1sec of data? Thank you for any help you can provide!

The default history length of a chart is 1024. To make it longer is a right click option.

Configure x axes waveform chart

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