Can waveform chart be given focus when modifying y-axis numeric scale

Hello,
I have an application where I have a waveform chart (LV7.0) and a string variable on the same screen. Since, in this application, a user inputs data into the string with a bar code reader, and since that can happen at any time, I constantly give the string control key focus. This is done within a loop. The problem is, I want to be able to double click the y-axis scaling on the chart and modify it at runtime, effectively zooming in or out on the chart. Ideally, during modification of the chart, the chart would have key focus, and I'd set keyf ocus on the string control to be the inverstion of the key focus of the chart... but that doesn't work. Does anyone know how to do what I'm trying to accomplish?
Thanks.

Hi rickford66,
i think you can use an event structure for it. Set the key focus of your control in the timeout case. You can change the timeout depending on the user events. Another solution could be to use the key down event of the VI to read the barcode.
Hope it helps.
Mike

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Why do my Waveform Chart Grid Lines Disappear when this runs?

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I have a Waveform Chart that Im using. The charts grid lines are initially set at 1 min intervals...which works fine
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Attachments:
JH_waveform_graph_markers[1].vi ‏25 KB

Hi hova2010,
Please keep your questions on the same issue to a single thread. Thanks!
Thank you for choosing National Instruments.
Aaron Pena
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http://www.ni.com/support

Export Waveform Chart Plots data to spreadsheet file based on X scale (Time Stamp) min and Max Value

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Query 1:I am trying to export the Chart data(Total plots 6 ) only between the X scale Min Time and Max time limit .
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Hi selvan,
1) read the chart history (or better keep a history in your own shift register) and limit the data to the XMin and XMax values (read all those chart settings from its properties). Then save the data using WriteToSpreadsheetFile…
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How can I update the x-axis to match a time reading in a waveform chart?

I am recording data in real time and displaying it in a waveform chart. However, I have yet figured out how scale the x-axis to match the actual time scale of my data. I've played with the accompanying property node but that has not produced the desired result. My guess is that there is a combination of xscale.range.maximum and xscale.multiplier values that need to get updataed in a certain way, but how is still unknown to me. If you could assist I'd appreciate it.

Nobody has recomended using a Waveform Chart!
A waveform chart will plot the points based on the "t0" of the waveform.
The waveform chart will maintain the buffer so all you have to do is apply the new data.
The "t0"'s of updates from more than one plot do not have to match-up.
See the attached LV7.0 example and jpg.
Ben
Note:
"t0" values for an individual plot must be increasing values.
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction
Attachments:
Wform_Times.vi ‏58 KB
Wform_Times.JPG ‏102 KB

Multiple values in stacked waveform chart...how to?

I am using a single waveform chart which is staked showing 3 Y-axis value on single X-axis platform.....more clearly I have bundled 3 values and connected to single waveform chart......Now, I want to add one more variable to each staked Y-axis....such that my each staked Y-axis have two variable....so that 6 y-axis variable in 3 staked plot(2 in each) having single platform of x-axis in single waveform chart.......
how to do that?

There are 2 vis that do this. Attach is my chart.
Attachments:
Chart_Ini_Elnik-II.vi ‏24 KB
Chart_Time-Init_No-Hist.vi ‏20 KB
chart.png ‏92 KB

Waveform chart slow to read samples AIs when sending AOs

Hi all,
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However, when I send the AO pulses labview seems to "freeze" or "suspend" until all output pulses are sent... This is very apparent with a high number of pulses (e.g. 10 pulses at 50Hz)... That is, the waveform chart freezes/stops scrolling until all AO signals are sent, then the chart updates all the pulses in one hit and continuous displaying data; rathe than have each pulse displayed individually...Why concern is that AI during the AO phase may be losted ot not sampled properly...
Can anyone provide me with an explanation for this behaviour? I am using a LV2010SP1 and a USB-6218 BNC multifuction DAQ.
Thanks!
Jack
Attachments:
TMS2.vi ‏304 KB
TMS2.vi ‏304 KB

Hello Jack,
Reviewed the code.
Remember The way labview executes code, Labview executes code by flow of information meaning that it is going to wait untill the neccesary items are ready before executing the next part of the code.
For example If we want to make a simple add function for "x" and "y" labview is going to wait untill both inputs are ready for operation before operating and outputing "z" as a result.
It does it the same way everytime. I took the time and rearranged the code so we can understand it better, The execution happens from left to right, from top to bottom.
If we refer to the image, the arrows show us the flow of information of the VI, The DAQ assitant, the filtering of the signal and the Triggering is done before you actually output data through device1 analog output.
The code is expected to work that way cause it waits untill done acquiring with the DAQ asistant to start generating an output.
I can think of different options,
-You can modify this VI so that the output takes place regardless of the input data
-Having two different vis where you can set the read and write at different rates, using a functional global variable.
-Using a producer/consumer architecture.
This is an example that I think might be useful.
Using Producer/Consumer Architecture for DAQmx Read and Write to File
Hope this was helpful,
Luis Martinez.
Applications Engineer.
National Instruments.
Attachments:
Flow.JPG ‏146 KB

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.
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Attachments:
error8.JPG ‏8 KB

How can I change the color of plot in a waveform chart and graph?

There are 4 plots in a waveform chart, from plot0 to plot3, and I want to chang the color of plots dynamicly up to my needs when the VI is running.
For example, as show in the picture, i want to set the plot0 as RED, and plot1 is BLUE, plot2 is YELLOW, plot3 is GRAY.
If there is only one plot, i can change it's color, however when there are more than one plot, it fail.
How can I do it?
Thanks
Attachments:
waveform.JPG ‏61 KB

Hello MilkyStone,
first you have to set the active plot, then change its color (or other properties). All that is done using property nodes.
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Using Waveform Chart, inconsistent results when setting X range and delta X properties

I have isolated my problem to a simple vi consisting of only a waveform chart (attached). I am using LV 5.1.1. I have used an attribute node to set x minimum to 0, x maximum to 10, delta x to be entered by the user, and have turned autoscaling off.
When I plot 2 random points, x maximum is inconsistent, and doesn't stay at 10 when the vi is run several times in a row. Specifically, the first time the vi is run (after delta x is changed), x maximum changes. Then, the second time it is run, the max typically goes back to 10. However, when run several times in a row, x max will fluctuate. Specifically, I tried entering a delta x of 8. Mostly, the min is 0, max is 10,
and the line between the 2 random points plots from 0 to 8 along the x axis (good). However, every once in a while, the x max will go to 8.
This behavior is very strange, and will not allow me to program my actual application correctly until I fully understand what is happening. I would assume since Waveform Chart has these attributes to set, I can still using the Waveform Chart, and don't have to completely restructure my program to use another display.
Attachments:
deltaX2.vi ‏28 KB

That is the expected behavior, it is only that you don't assign the properties in the right order. If you set the XScale.Multipler before min and max all is how you expect it. When you set the multiplier, min and max are automatically changed to reflect the scale changes thus overwriting your previous settings.
LabVIEW, C'est LabVIEW

Horizontal scrollbar of waveform chart in tab page resets to end when tab page switched

I've got a VI in LV 2012 with a chart in one of two pages of a tab control. Whether compiled to an executable or not, when the waveform chart contains data that is no longer being updated and the x-axis range doesn't show the last point of data, the horizontal scroll bar auto-adjusts to show that last point if you switch pages (back to the chart) on the tab control. I've tried turning off Autoscaling but that doesn't stop the effect.
Additional issues:
On some of these attempts at reproducing this, the X-Axis will even change scaling, zooming in on the data.
When data is pushed left by this bug to allow displaying the furthest data point, if the leftmost area of the chart was blank before the data was pushed left, the data pushed left into the formerly blank area will not be displayed. This happened only when the X-Axis was manually autoscaled prior to pushing the data off the right edge of the chart, and only if the x-axis scale was not changed. If the tab pages are again switched at this point away and back to the chart, the data re-appears.
The chart is a stacked plot if that makes a difference, Also, the tab control is not linked to any event handlers.
Also, the scrollbar works fine if you scroll such that the rightmost data points are on the chart along with blank area to the right, whether there is more data off the left edge of the chart or not.
Last, the Y-Axis of each stacked plot is unaffected by any of this.
I hope this isn't a duplicate - I didn't find it in the forums.
Thanks,
Erik
Attachments:
Flaw Demo.vi ‏120 KB

Alex,
Thanks for the quick response on this. Again, the charts are awesome except for these minor fiddling details. Sorry about the terminology confusion - I didn't find anything in the Help system naming the legend buttons, and unfortunately I can't edit the prior post. When I said "AutoScale LocK" I meant "Scale Lock", and "AutoScale Once" I meant "Autoscale".
Here are the issues, hopefully clarified:
1. If any chart elements have Scale Lock set, pressing the AutoScale button for any plot causes these other plots to autoscale as well. Note these are not plots with multiple Y scales, they're stacked plots with separate y-scales for each plot. Changing the "Advanced->Auto Adjust Scales" parameter had no effect on this issue.
2. If none of the chart elements have Scale Lock set in the scale legend, pressing the Autoscale button for the X-Axis has no effect if the x-axis was previously set to show all the data history but then panned such that some data falls of either side of the chart.
This may have been confusing, so here's a breakdown of the steps to re-produce the problem using the VI I previously attached.
a. AutoScale all elements of the chart, and turn off Scale Lock on all elements
b. Move the data to the right in the chart, so the left half of the chart area has no data (e.g., set the X-Axis range to -5 to 6 seconds)
c. Press the X-Axis AutoScale button. The X-Axis range will not change from where it was in (b).
3. The Y-Axis will also auto-scale when returning to the Chart tab if Scale Lock is enabled for the plot with the fix for the x-axis scale in place (restoring the Xscale.Range parameters from a local variable). If the fix is not performed, this doesn't happen.
4. Pressing the Scale Lock button on one of the plots causes the X-Axis scale to be lost IF there is data past the maximum displayed X-Axis range. It looks like it set the X-Axis to the same problem range as before the fix was in place. I don't know how to build an event case for this, except for possibly "Mousedown?".
One more:
5. Enabling Scale Lock on any plot auto-scales any other plot that has Scale Lock enabled (assuming the user changed the Y-Axis range from the previously auto-scalled range). Obviously this is linked to #1 above, but worth noting.
Thanks again, Alex!
Erik

Waveform chart X-Axis reverses itself when upper limit is edited in Absolute Time - problem may be linked to Timestamp Control?

I've seen this problem for some time now, and it still exists in the Silver toolset Waveform Chart in LV 2012. If the chart is in strip mode, and you edit the upper limit value to a point in the future, the X-Axis will invert (higher values/ later time to the left), to the limit of the Chart History length. This happens whether the chart is active (logging data on a compiled executable) or even when in design mode, though it's more consistent when there's data in the chart. It's not history length related as far as I can tell, as I set the length to 7 days of sampling @ 1-second intervals (605K), and it happens when I try to set the end time to an hour in the future with only a few minutes of data collected - suddenly the right Absolute Time becomes the time my last sample point was collected, while the left Absolute Time becomes nearly 7 days in the future (so neither end point is what I was setting it to).
It's nice that the chart gives the option of editing the limits, but as such, it's important that they work as you would expect them to.
Also - until this is addressed, is there a way to lock it against editing? Until a fix is made, my workaround is to put a transparent button over the range start & end points, and a transparent flat rectangle above all other mid-range points, and pop-up a data entry form with a Timestamp control to allow editing. Unfortunately, this doesn't work as I would expect, as typing "11 AM" in the Timestamp control over a prior value of say "10:05:34.232 AM" ends up becoming "11:05:34.232 AM" instead. ??? Another error - or is this by design? If it's by design, is there an option to make it behave as I would prefer (11 AM = 11:00:00.000 AM), as Excel behaves with timestamps? I can't help but suspect this may be linked to the chart axis issue.
Also - I just built a simplified chart modeled somewhat on my current project, and could not get this to recur. BUT... had the strangest thing happen: My sample data was generated using the Trig functions for Sine and Cosine, and at one point my waveforms distorted on the display, so I'm attaching that here plus the simplified chart project.
Last - my system is LV 2012 on Win7 Pro-x64.
Thanks!
Erik
Attachments:
Chart data distorted.png ‏45 KB
Waveform Chart Flaw.zip ‏17 KB

I am not so sure that this is a bug, and I have not been able to reproduce this behavior that you are describing.
But you can lock it from editing by right-clicking on the graph and go to Properties>>Appearance>>Enabled State --> Disabled
Also, word of advice for the future: You will get more replies from the community with shorter posts and keeping it to one question per post. Summarize what the issue is, and put the detailed documentation and instructions to reproduce in the actual VI.
Huntington W
National Instruments
Applications Engineer
***Don't forget to give Kudos and Accepted as Solution where it is deserved***

Why does Waveform Chart Initalized by Property nodes behave erratically when hidden such as by the Tab Control?

I am using wave form Chart on a tab control. The problem is that the chart works fine when it is showing. I can stop the data and reset the chart history successfully. The Fun begins when I go to say Page 2 of Tab control ( The wave form Chart is on Page 1). If I now try to initilize my chart with offset, multiplier, min and max rage values - The chart assumes values on the X scale which are arbitrary. I can see this when I go back to Page 1.!!
But If Page 1 were showing and I did the same Operation The chart behaves as I expect it too.
Can this behaviour be explained? How do I resolve this Problem? Also I have Observed that from time to time the Sca
ling on X Axis may also change when the Chart is Hidden by the tab control. I have not been able to identify the reason for this, It is totally random.
Good Luck!
Mache
Attachments:
Time_Tab.vi ‏50 KB

I did a similar workaround ...
Everytime I Toggle the Run Button, I am making sure the active Tab is the one with Waveform Chart. This way the waveform Initializes fine. Then I try to Switch the active tab back to its One Previous Value, programatically - So that the user may have somewhat seamless interaction.
There is one hitch however - The waveform Chart needs some time to initialize and my data stream is also coming at every second. So if I switch Immediately to some other tab, Sometimes I am successful, Sometimes I am not. Again this depends om System Speed and such. If I update the Tab Control at the next iteration, it is very irritating visually. So I left the Tab control at the waveform chart after reset. If the User wants they can switch it Bac
k.
Of Course the best thing to do is don't Reset. Referred the problem to NI Apps. They said it will be fixed in the next version.
Well! Got to make enough money without resetting so that we can buy the new Version, which will reset!! Ciao! And Thanks for your answer.
Regards,
Mache
Good Luck!
Mache

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 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!

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Can waveform chart be given focus when modifying y-axis numeric scale

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