Waveform chart Display

Hello
i am try to make my waveform chart as accumlate data which mean that it will not over write the old measurnents but instead will display all
from the begining of time
can anyone help me?
thanks in advance

Sorry, I don't have DAQ drivers installed, so I cannot really inspect your code.
Still, there are some beginner mistakes that should be corrected.
The loop all the way on the left uses 100% CPU doing nothing but spin millions of times per second. Place a small wait.
Instead of a sequence structure, use a state machine architecture. Much more flexible.
If the code is sitll in the first frame, pressing start would lock up the VI because the event cannot be handled.
If you would make some of your booleans latch action, the local variables would not be needed.
Why do you even use the event structure and event loop? Just wire the START button (switch action) to the outer case structure. Wire the ON LED to the same wire.
You don't use the timeout event, so why is it there?
Explain the purpose of the two charts.
Since the while loop could go on forever, you potentially have an unlimited amount of data to retain. Is there an upper limit? No computer has unlimited memory. Maybe you should stream the data to disk and just display the last few thousand points on the charts.
LEDs are typically indicators and don't make good controls (Start Lock).
LabVIEW Champion . Do more with less code and in less time .

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Combination of Stacked & Overlaid Waveform Chart

Hey everyone,
I've got a challenge for you that would really help me out. I'd like to use - specifically - a waveform chart to display four parameters overlaid on two divisions (in stacked mode) i.e. two parameters plotted on the first division and two parameters plotted on the second division with no additional divisions possible. I have an example attached that gets me halfway there (written in version 8.2), but I can't seem to figure out how to make the waveform chart display only two divisions instead of the four dictated by the bundle tool. I suspect this isn't possible as I can't seem to find a property that allows me to control the number of divisions displayed but hoped that someone else might know a trick or two to disable those pesky additional (and blank) plot fields.
Thanks in advance for any help!
Andrew
Attachments:
Overlaid and Stacked Waveform Chart.vi ‏22 KB

Here you go....
there should be enough here to get you what you need.
1:30 Seconds ARRRGHHH!!!! I want my popcorn NOW! Isn't there anything faster than a microwave!
Attachments:
2 Traces per Plot Description.pdf ‏71 KB
2 Traces per Plot Description.zip ‏182 KB

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

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

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.

Combining 2 readings into a waveform chart/graph displaying continuous readings of data from different sources

Hi,
In the file
(Serial Read and Write to .tdms & Compare on Graph – test.vi) I am trying
to integrate the following two waveforms into a single waveform: Realtime
reading and Waveform chart (open vi to see). Both of them display speed vs time
but from different outputs. One comes from an excel file (Teraterm – Results.xlsx
– sheet 4, (column 3:row 4) to (column 3:row 1878)) and the other comes from
the Serial input which is in Hex format and is split to get the various readings
of speed, voltage etc. I have already wired speed to a variety of waveform
outputs, but all result in broken wires.
The readings are taken in by the program
and but I am unable to wire the two readings together into one graph.
Please do let me know as to how can I make this work.
Thanks in Advance.
Best Regards,
Akhil
Kumar Meesala (Mr.)
Year
4 | Undergrad | Mechanical Engineering
National
University of Singapore
Email:
[email protected]
Mobile:
(+65) 9326 7069
Solved!
Go to Solution.
Attachments:
Serial Read and Write to .tdms & Compare on Graph - test.vi ‏58 KB
Teraterm - Results.xlsx ‏593 KB

Dear GerdW,
I'm sorry again about the misspelling your nick.
I tried connecting a waveform chart to the two terminals (speed from the DAQ and speed from the excel file) but I was unable to get the connection right. I understand that charts are used for readings which are equally spaced out, whereas XY graphs are used when the readings are not be spaced out uniformly. But I am unable to wire the connections correctly.
Actually the DAQ device continuously sends out data through the serial port. So I would not run out of data . Are you referring to the data coming from the DAQ device or the excel file? I actually have not thought of what would happen when the excel file would run out of values I am just hoping for the software to run till then for now
I have cleared up the wires as well Thanks for your help.
Best Regards,
Akhil Kumar Meesala (Mr.)
Year 4 | Undergrad | Mechanical Engineering
National University
of Singapore
Email: [email protected]
Mobile: (+65) 9326 7069
Attachments:
Get Excel Values.vi ‏25 KB
read_excel_values.llb ‏201 KB
Serial Read and Write to .tdms & Compare on Graph - test.vi ‏79 KB

How to display value in waveform chart

dear sir
i am using labview 7.0 with dsc module for scada.
now i want to display the difference between two tags value in waveform chart. Also i want to display that difference value on y axis and system date and time on x axis continously. Also if there will change in that tag value then there should be reflection of that value on wavwform chart with system time. Really i am in trouble. please help me.
falgandha mohire

Nadim,
Why would an XY graph be preferable to using a Waveform Chart where the "t0" is the time of the measurement?
I don't get it.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

How to set maximum number of data points displayed on waveform chart?

I have a waveform chart set to x-autoscale, but after about 1000 data points, it begins to scroll again. How can I display all of the data points being collected, say 2000 points?

Right click on the chart and select Chart History Length. Enter the value that you need. The maximum is 2147483647 points.

Why does AI Read(Asynchronous).vi cause the waveform chart to not display any history ?

I trying to create a strip chart for 16 channels that will require displaying 10-20 minutes of data.It also starts a separate vi to set gains and offsets while displaying the data. Using AI Read.vi uses 100% of the CPU so the second vi does not run. But using AI Read (async).vi allows the second vi to run, but causes the waveform chart to not display the history? I'm using LabView version 6.0.2.

Hi Waynes World,
I have a couple of questions that may help us solve this issue...
1) If you are modifying one of our example programs, which one did you start with?
2) What kind of analog input are you doing? Buffered? Finite or continuous?
3) Have you tried increasing the buffer size of the strip chart? This will allow the chart to store more data in it.
4) When you use the Async VI, and when you are using the other, can you describe how the strip chart is showing the data... does the data in the chart keep growing and growing... or does it clear itself and start over when the pine reaches the end?
I think this issue is rooted in how the buffer is being used with the two different AI Reads and how it returns data to the chart.
On a side note, have you considered upgrading to a newer version of LabVIEW? Our latest versions of LabVIEW come with many new features and it is signifigantly easier to use.

Waveform data could contaminate x axis display in waveform chart?

Hello
Please take a look at this vi:
Attachments:
Real-Time Chart.vi ‏19 KB

Ben wrote:
It looks like you are getting bogus time stamps from the SV.
This thread talks about the chart and waveforms.
Try click the Chart on the front panle to find the ignore...
Ben
As far as I understood this example uses "t0" from the waveform data for x axis. I tried this method and it works. The date and time shows correctly. That's great.
But I actually have another request for the chart display, that is to show data in a certain time period, which should be programmable. For example I could let the chart show the data waveform in 10 seconds this time(I mean in one screen without scrollbar), and the next time I execute it, I change the parameter and show the data waveform in 60 seconds.
I tried to modify the initialization like that:
I thought by changing the maximum value of the scale range, I could realize that. This kind of setting didn't really work. before the breakpoint, the time in x axis became chaos again, and after going into the loop it returns to correct value.
Do you have any ideas how to realize that?
Thanks again!
Best regards
zzha

How to display two waveforms in one waveform chart?

hellow!anyone can tell me how to display two waveform together in one waveform chart? thanks!

Hello,
An easy way to tell how to make multi-plot charts and graphs is to hold your mouse over the chart/graph terminal on the block diagram and make sure Context Help (Help >> Show Context Help) is enabled. This screen will tell you how to connect the indicator for a multiple-plot display.
You might want to take a look at my attached screenshots of a working multi-plot chart.
Hope this helps!
Liz F
National Instruments
Attachments:
Multi-plot_chart.bmp ‏902 KB

How to use ni-6008 and build a four channel data acquisition at a rate of 250 samples per channel and display all the data in a waveform chart

how to use ni-6008 and build a four channel data acquisition at a rate of 250 samples per channel and display all the data in a waveform chart

Hi kdm,
please stick in one thread for the same topic!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Painting Error while displaying Waveform charts in subpanel

Hello:
I've been using subpanels for a while without problems. Recently I've
noticed a painting error when I load a VI containing a Waveform Chart
into the subpanel. The label of the Y Scale of the waveform chart
doesn't show, instead a black rectangle appears. This problem can be
seen in the VI viewer.vi, in the subpanel examples of LabVIEW. I know
this is not a big problem, but I'd like to know if there's a way to
correct it.
Thanks in advance.
Robst
Robst - CLD
Using LabVIEW since version 7.0

Hi Robst,
This is a known issue with LabVIEW 7.x. Happily, it has been corrected in LabVIEW 8.0. There is a "quick and dirty" workaround (courtesy of Marc A http://forums.ni.com/ni/board/message?board.id=170&message.id=155006&requireLogin=False) that I hope you will find satisfactory. The background of the Y axis label is clear by default. If you manually change it to the color of the graph, then when you view it in a subpanel it will not turn black.
I hope this helps! Let us know if you have any further questions!
Megan B.
Applications Engineer
National Instruments

Saving array data from a waveform chart

I am using a CRIO 9004 and a 9237 bridge module to measure some strains from strain gauges. I've got one timed loop that reads the DMA FIFO and puts the arrays of values (16 data points, 4 per channel) into a queue. In the consumer timed loop a For loop scales the binary data, auto indexes it into arrays, then the arrays are merged into a 2D array for the four channels displayed on a waveform chart . Everytime the consumer loop runs it indexes 4 data points (per channel) yet the waveform chart plots them in a consecutive manner and doesn't overwrite the previous four. If I convert the arrays to waveform arrays I don't see anything on the waveform chart.
If I pass the 2D array of data to a array indicator inside or outside the consumer loop I get only 16 data points. I want to save the information that appears on the waveform chart after the consumer loop but because I'm not using waveform data type I can't use the write waveforms to file vi. The waveform chart history buffer has been set to 195360.
Idealy we will run the four channels for 120 seconds charting the data and saving the data. The minimum data rate is 1613kS/s (403 per channel) The data can be saved after the loops have finished gathering and processing or while they are running. I noticed when I tried to write to TDMS it slowed the consumer down. Same thing if I use a shift register with the volume of data.
I suspect I'm not sending data to the chart in the correct manner ( usualy takes two attempts to "clear chart" using shortcut menu). I'm not too familiar with timed loops /producer consumer loops and just tried to put something together based on examples.
I've attached my host vi and front panel screenshot.

Hope they appear attached this time.
Attachments:
Basic DMA (Host).vi ‏444 KB
screenshot2.jpg ‏113 KB

How to show two different plots with current system time and date on waveform chart

I am using one waveform chart to display the more than one value continiously. The data are comming properly but i am not getting my system (pc) time and date on x axis. It is showing default date and time (i.e.01/01/1904 5:30:45). Please give me suggestions to display the real time and date on x axis of waveform chart.

How does your data look like? Do you graph waveform data types, dynamic data, or plain arrays/clustes? In the case of plain arrays, you need to set x0 to the absolute start time of your data, e.g. with a property node.
I you would attach your code (or an image) we could offer more specific advice. There are too many possibilities.
LabVIEW Champion . Do more with less code and in less time .

Waveform chart Display

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