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gstroud
6 Posts |
 Posted - 12 Jun 2007 : 20:12:07
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Hello
I'm having a hard time try to get my data point to plot at the right time. For example I'm trying to plot 250 point/second with a visible time frame of 5 seconds. I can get it to plot them to the second, but it needs to plot (UpdateDraw) them smoother, so I tried to plot them at fractions of a second, but at that point I cannot get it to plot the 250 points/sec. It's displaying them way too fast.
I tried to load all of the data points (about 65,000 of them) up front before graphing them, hoping to control the speed of display but all it does is show a set of plotted point, no scrolling. I'm assuming it's showing the final 250*5sec worth of points, but the x axis values are inaccurate.
Can I not load all of the data points with the proper time values (each incremented 4 milliseconds)? When I debug the times are correct for each value. If I call UpdateDraw every second shouldn't the component know to grab the next 250 points?
Any help would be appreciated.
Greg |
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quinncurtis
1586 Posts |
Posted - 13 Jun 2007 : 09:21:20
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Sorry, but I can follow very little of what you describe. About the only thing I understand is the first sentence. When you state " I can get it to plot them to the second, but it needs to plot (UpdateDraw) them smoother, so I tried to plot them at fractions of a second, but at that point I cannot get it to plot the 250 points/sec. It's displaying them way too fast.", I don't have clue. If you have everthing working at 250 points/second, and only want some improvement in the display, try and explain in much greater detail exactly what you mean by smoother.
"I'm assuming it's showing the final 250*5sec worth of points, but the x axis values are inaccurate". It is very unlikely that either the points are being plotter wrong, or that the axis value are not correct. Ramp up you data values at known rate so you can tell where you are in the signal and you will find that the data is always plotted correctly, for the given coordinate system.
Answering your last paragraph:
"Can I not load all of the data points with the proper time values (each incremented 4 milliseconds)? Yes, apparently youv'e done it. In that case you can manually scroll through the data. See our QCChart2D example program FormControlExamples.LineplotScrollbar.
"If I call UpdateDraw every second shouldn't the component know to grab the next 250 points?" No, the component doesn't know anything like that. UpdateDraw will always display all of the data, clipping it to the x- and y- range of the current coordinate system. You probably have a ScrollFrame controlling the coordinate system range, in that case the ScrollFrame scales the coordinate system to show the most recent data, according to the parameters the ScrollFrame was setup for.
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gstroud
6 Posts |
Posted - 14 Jun 2007 : 00:18:37
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What I'm trying to do is use this tool to create an eeg monitor. Lets take an example in which I need to show 5 seconds worth of data before it starts to scroll. I don't have a problem showing th 250 points per second. I would like for the data to be seen quicker, that way it looks like the line is drawing across the screen instead of just plotting 250 at a wack. I don't know how else to explain this. Your example of the polygraph is too choppy. If you have ever seen a heart monitor or ekg monitor you see the line draw in milliseconds creating a smoother rendering of the data plotting across the screen.
Using the PlotLineScrollbar will not work. I don't want them to manually scroll thru the data, I need it to render smoothly across the screen in which 250 point are plotted every second, but not in chunck of 250 every second.
Hope I'm making more sense.
Greg |
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gstroud
6 Posts |
Posted - 14 Jun 2007 : 01:39:55
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I've worked with the TimeSimpleDataset and I was hoping that I could have complete control over when to render the data via a timer, but it looks like what you mentioned before... that it will display all of the data at once, which is not what I want.
Greg |
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quinncurtis
1586 Posts |
Posted - 14 Jun 2007 : 08:47:41
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We have to assume you have gone through our example programs. Please explain why the FetalMonitor example, or the Treadmill example, both of which have scrolling EKG displays, are not suitable examples for what you describe. In both cases you can make the ScrollFrame ScrollRescaleMargin = 1.0, as we told you in a previous thread, for the scrolling to always reset at the left edge of the plot. Also, look at our simpliest example program, ScrollApplication1, which is not cluttered up with a bunch of other display elements, set the ScrollRescaleMargin = 1.0, and expain why that is not a suitable example for you to follow.
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timely display of data
