Legend for multiple waveform chart
I have a Waveform Chart (and legend) with multiple waveforms. I can control the visibility of a given waveform on the chart programmatically using the "ActPlot" and "Plot.Visible?" properties.
Is it possible to programmatically make the legend only contain the plot names that are visible at any given time?
Cheers,
Dan
Dan
CLD
Hello DanB,
Following along the lines of what smercurio_fc suggested, you can use the Legend>Number Of Rows property (LegNumRows) to change the number of rows of your legend to the number of plots you are viewing, and then use the Plot>Plot Name property (Plot.Name) to edit the names of the plots yourself. I cannot see a property to extract these names dynamically, so this is probably your best bet.
I hope this helps, otherwise please do let us know if there is anything further,
Kind Regards,
Michael S.
Applications Engineer
NI UK & Ireland
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Synchroniz​e reset of multiple waveform charts
My main VI has multiple sweeping waveform chart, base off the Continuous Measurement and Logging template. I want to be able to change x axis range (toggling between 10 seconds of data and 3 seconds of data)
I did it by changing the X scale range min to zero and max to the appropiate sample size, and clear the history. While this works for each chart they always ended up off sync instead.
At first I thought that's because I put it in a ub VI. But moving everything to te main vi does not change the behavior.
Any ideas? Thanks.
Solved!
Go to Solution.Well those all have to run sequentially in the UI thread so there is no way to do them "Simultaineuosly" HOWEVER, if you bookend those property nodes with an Involk of the method Defer FP Updates (True then False) you'll see much more what you expect.
Tighter alignment of the "Clear Histoys" would also be done by splitting up your p-nodes so do all of them at first then change all the scales.
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Multiple waveform chart automatic plot
Hello
I need to plot multiple signals in the same waveform chart. The problem is that the number of signals is not constant. I have a control that enables me to change the number of signals to plot each time I run my VI. Is there any way to do it?
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JoãoHello,
I don't see many other way to do this...
You could also manualy enable or disable charts but i don't see a way to do this in a synamic way...
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Richard Keromen
National Instruments France
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Strictly typed refnum vs normal refnum for a waveform chart
I know that one way of clearing a waveform chart is to write an empty array to the 'history' property of the charts property node. The help file for this states: "use strictly typed refnums when reading this properrty"
I am looking at a program coded in LV 8.6
a number of control refnums are carried around in an array (so strict typed)
in some cases (but not all) the programmer used "to more specific class" to designate a waveform class when writing to properties for scaling the Y-axis, etc. Other times this is not done(?)
We are now having an issue which appears to be that the chart is re-initialized when dynamically rescaled (I am not sure if that is what is going on, but that is what it looks like).
It looks like when the chart is dynamically rescaled the previously acquired data is gone and the chart starts populating fresh.
Haven't figured out what is causing this, and I am wondering if strict type refnums vs generic refnums may be a factor?
Lawrence M. David Jr.
Certified LabVIEW Architect
cell: 516.819.9711
http://www.aleconsultants.com
[email protected]Waveform charts can hold different data types (they are polymorphic), such as DBL or 1D-array of DBL. When you want to set the history, you need a 1D DBL or 2D DBL respectivily. The correct data type is part of the 'strict type', I guess you will get the default instance if you use the non-strict (generic) type.
But if this is releated to your problem, I can't even guess.
Felix
www.aescusoft.de
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Legend for a line chart displaying incorrectly
Hi All,
I am working with a line chart in webi XI R2. for example conssider the island resort marketing universe. we have 3 resort names like bahamas,US,France and the corresponding "revenue" for year 1999,2000,2001. Now i want a line chart for each resort and another line for sum of all the revenue.
So my final line chart contains 4 lines, one each for bahamas,US,France for 1999,2000,2001. and 4 line is sum of all revenues (for all resorts) in 1999,2000,2001.
I have used a "vertical line mixed" chart for this. All the graph lines are displaying correctly but the legend is displaying wrongly.
Please advise.Hi Raveendra,
I guess its the 4th line i.e. sum af all revenue that you have added in the same chart is causing the problem.
My solution is why dont you try and put the sum of all revenue in other chart on the same report.
May this would help resolve your legend problem.
If you can give the exact details like what attributes you have selected while running the query and how did you added the sum of all revenue in your chart being more specific, would rather help a bit better in solving the problem.
Thanks,
Chirag Desai. -
Scrollbar for a waveform chart
Hi, I make the scrollbar visible in the front panel, but it's always gray out as shown below. How can I fix this? Thanks!
Solved!
Go to Solution.Hi kwang,
switch off x axis autoscaling…
As long as the x axis is autoscaled (and so shows all available data) there is no need for the scrollbar!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome -
Cursor legend for waveform chart
Greetings again. Is there a method to turn on the cursor legend in a waveform chart (like in the waveform graphs)? I'd like to allow a user of my application to be able to select a portion of a chart and have the application report the value plotted.
I am acquiring data via the Analog In channels of a PCI-6036e at 1500 Hz to plot in real-time. I tried plotting my data with the waveform graph but it only shows the latest readings and does not scroll the data. I know I could build an array and rotate through it as the data comes in but that seems like a lot more effort just to be able to use the cursor controls to highlight data.
Any ideas? Am I being too brief?
Thanks-
-dennis.Cursors are only avalaible on graphs, not charts. There was a post on this subject yesterday...
See http://forums.ni.com/ni/board/message?board.id=170&message.id=102968&jump=true
CC
Chilly Charly (aka CC)
E-List Master - Kudos glutton - Press the yellow button on the left... -
To more specific class for waveform chart
Dear All
In the attached VI diagram the "To more specific class" gives an error messag:
LabVIEW: Type mismatch: Object cannot be type casted to the specified type.
so it can not work for my waveform chart. I think I changed some properties or some thing similar for my chart that can not work with this routine because it works for new instances of waveform charts but whatever I try to find the difference between my waveform chart and a new instance of waveform chart I don't not find any difference.
Do you have any clue?
Best regards
Afshin
Attachments:
VI2.JPG 59 KBTry to use the "Controls[]" and the "ClassName" property instead. See attachment.
Best regards
chris
CL(A)Dly bending G-Force with LabVIEW
famous last words: "oh my god, it is full of stars!"
Attachments:
WaveformChart.JPG 61 KB
WaveformChart_85.vi 18 KB
WaveformChart_85_CTL.ctl 9 KB -
Average value for waveform chart
Hello everyone.
Can i make a time interval, where i can measure average value for a waveform chart ?
for example fom 0:30 to 0:45
I have uploadet my VI
Thanks in advance
Oesen
Best regards
Oesen
Solved!
Go to Solution.
Attachments:
Trykmaaling.vi 83 KBOesen,
When you are displaying data on a chart, the newest data is appears at the right of the previous data. When the chart history buffer is full (default length = 1024), adding a new point deletes the oldest point. Visually it appears that the data slides to the left as new data is added to the right end.
My question relates to how the user would "tell" the program what data to average. In the image you posted you marked a segment of the data to be averaged. Suppose the user marks point "A" as the beginning of the segment. While the user is deciding where to put mark "B" additional data is acquired and point "A" disappears because it is beyond the history length. What does the program do in such a case? A slight variation is the situation where both "A" and "B" have been marked but some of the data is deleted from the history before the averaging or other processing has begun.
Lynn -
Waveform chart time axis is not matching the waveform data
So here an interesting conundrum I hope you might be able to help me with...
My VI has waveform data sent to a chart, though the data is not being plotted against the current time. Rather, it is being plotted starting way back in the reference time (way back in 1903). I don't understand why this is happening. When I build the waveform, I use the "Get Date/Time in Seconds" function outside the while loop and feed that into my "Build Waveform" Function as the t0 value. My dt value is 0.05 (20 Hz) and then I feed in my array of data in the Y input. Any ideas why the chart is plotting this data over 100 years ago? Thanks!
AndrewHiii, Ronin
Here is your solution.
By default, waveform charts and graphs display the absolute time at time 0 as 7:00:00 PM, 12/31/1903 on a Windows based system. Property nodes can be used to get the correct absolute time to display on the x-axis of the waveform chart.
First, right click the chart on the front panel and select X Scale >> Formatting. Then set the format to Absolute Time.
Create a property node for the waveform chart by right-clicking on the chart on the block diagram and selecting Create >> Property Node. Expand the property node to display two properties. Select the Format property and the Offset property. The Format property is located under X-Scale >> Format and Precision >> Format, and the Offset property can be found under X-Scale >> Offset and Multiplier >> Offset. Right click on the property node and select Change All to Write.
For the Format property, the context help shows that there are multiple inputs to this property. Wire in a value of 7 to set the format to Time and Date.For the Offset property, first wire the output of the Get Data/Time in Seconds VI to the input of the To Double Precision Float VI. Then wire the output of the To Double Precision Float VI to the Offset property.
In addition, if you know the number of data points plotted to the chart per second, you can set the Multiplier property located under X-Scale >> Offset and Multiplier >> Multiplier. If there are x data points generated per second, wire in a value of 1/x to the Multiplier property. A simple example program "Chart with Timestamp" that demonstrates how to do that is attached.
Thanks,
Nishant
Attachments:
Chart with Timestamp.vi 36 KB -
How do you set the size / bounds of a waveform chart at run time?
I have a plot area that I would like to fill with as many waveform charts as the user specifies (at run time). The "bounds" property is read only and I haven't noticed an additional "size" property for a waveform chart as there is for a button. Is there a way to set the size of a waveform chart at run time, and if not, why not? (Labview 6.1)
Look at it a little more carefully, I suspect that your assumption is only half wrong. The property does only resize the plot area--LV resizes the frame to fit the resized plot on it's own.
You'll need to bear this in mind when you're figuring-out what size to set the property to.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps -
How to set waveform chart to start data since beginning of run
Solved!
Go to Solution.
Attachments:
TCs.vi 106 KBYou 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 -
How do you reset Waveform chart to blank?
I have a VI with a Waveform chart in the WHILE loop, and each time I STOP the vi and re-start it, the old data remains in the display and moves out only as new data is collected. This old data persists even after the VI is closed and re-opened.
Is there a way to remove the old data each time the VI is run, in other words to make the blank screen the default for the Waveform chart? Right now, every time I open and run the VI, there is a squiggly line in the display, from irrelevant/useless data collected previously, and it would be cleaner and less confusing if there was no old data displayed there.
Thanks,
Dave
Solved!
Go to Solution.Thanks, but, still confused. I already have a data source wired to the Waveform graph. I cannot wire two things to the Waveform graph...so...can you offer more information? See the vi below....Waveform graph allows only one thing to be wired into it....
Are you suggesting wiring an empty array each time I use the VI and then reconnecting the data source?
Attachments:
waveform graph question.jpg 19 KB -
Export all data from my waveform chart to excel
Hello, my name is Chris. I am just learning to use LabView. Everything I have learned so far is through these boards. Which is a valuable tool for someone learning. The VI I am working on is to monitor current from a unit we are testing. I am able to monitor current and have it running in what I believe to be real time. As I said, this is the first one I have made. I am trying to export all the data from my Waveform Chart to a report. Everytime I try I get one instance and it measures 0. I don't know what I am doing wrong. Any help would be appreciated. Also, if you have any suggestions on the all around working of this I would appreciate that as well. Thank you in advance.
Attachments:
Lp Current Test.vi 83 KBHey Christophrt,
If you are trying to display the microseconds for a waveform chart in LabVIEW here is how you can do it:
Go to the Chart Properties>Display Format>X-Axis>Advanced editing mode>enter:
%<%I:%M:%S%6u>T as the format string and you will have the hours: minutes: and seconds to the microseconds.
If you are trying to display the exported data in microseconds in Excel, you will probably have to do some formatting changes in Excel to have that work.
Regards,
Tommy G.
Applications Engineer
National Instruments -
Plotting multiple graphs on one waveform chart with dynamic data types
I'm trying to put multiple graphs on one waveform chart and having data agreement errors. I'm wondering if it has anything to do with the fact that dynamic data is being used (I've had no problems with other datatypes in the past). Does anyone know how to correct this problem? I've attached the following .VI. There will be plenty of .VIs on the bottom that won't load, but they are not consequential for this problem.
Thanks!
Brian
Solved!
Go to Solution.
Attachments:
Stiffness Control V1.vi 119 KByou could use stacked plots by right clicking on the chart and clicking on the stacked plots and than on the front panek you can put a bundle function on the FP and hook your signals up
Harold Timmis
[email protected]
Orlando,Fl
*Kudos always welcome
Attachments:
multiplotwaveform.JPG 138 KB
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