scrolling through chart history

[chadj]

I have a vi which displays a chart to continuously display the last 20 minutes of data which I've collected (so the Y axis is some value and the X axis is time). However, I would like two additional things which I'm unable to impliment: 1) the user should be able to scroll back through historical data and 2) they need to have a chance to view it so the chart should not jump forward each time a new datapoint is collected. Can anyone help me with these two issues?

[DBerry]

1) Setting the x-axis auto-scale off will allow the user to set the min/max range of the chart.  You could also add a scrollbar control and programmatically set the min/max range using property nodes to give the user a way to scroll through the history.

2) To prevent the new points from updating on the chart, you may be able to use teh "Defer Panel Updates" property.  Set the property to TRUE on a mouse down event for the scrollbar control from (1) above.  Set it back to FALSE on a mouse up.   If this doesn't give the proper functionality you could also try storing the history data in an array and plot to a XY graph (not chart) only when you want to refresh the new data point(s).

Dan

[DBerry]

See this other post:http://forums.ni.com/t5/LabVIEW/when-writing-new-value-to-chart-don-t-change-scroll-position/m-p/144...

You can add an x-axis scroll by rt-clicking on the chart - visible items - x-axis scroll.  

Dan