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obtain values of a plot in waveform graph

hi,

 

is there a way which I could get the values of a plotted graph in Waveform graph?? For instance let's say I acquire some sensor data and display in the waveform graph in real time. Once it is displayed, is there anyway I could obtain the values of the plot in an array which I could later write to a txt file or somethin?

 

I know it is possible to collect the data in to an array while the sensor data is acquired. I do not want to do this. I want to collect the data after the data is being plotted.

 

Thanks!

 

Regards,

Chathuri

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You must be using a waveform chart and not a graph since that is what is used to display one point at a time. A graph would have an array wired to it. To get all of the values currently displayed on a chart, you can use the property History Data. This is an array of values. The reason I say data currently displayed is that a chart has a limited length that you set with the chart history length. Once you reach the number of points specified with this, old data is dropped as new data is added.
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Hi, Thanks. I just tried it and it is fine. But sorry I forgot to mention earlier that my main objective is to get the timer scale value. How would I get this value?? Because when I checked with the history data property node I realised that the values I get is only for the Y scale but not for the 'time' scale.

 

Also where can I change the history data length?

 

Thanks!!

 

Regards,

Chathuri

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The x axis data is whatever you specify. With taking a single point, its the wait time you have in your loop. It has nothing to do with the values displayed on the chart unless the loop rate is 1 sec. That is the default for a chart and you need to change it to reflect the actual loop rate. Look at the example called Real Time Chart. There is no array of time values. Only a start time and a dt. You can of course easily create an array from those two values.

 

 To set the history, right click on the chart  and select Chart History Length.

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