how do i add a plot to a previously plotted graph

[amazed]

I have a graph that has plot.  I am gathering a new plot and want the graph to show how closely the new plot is following the previous(data is being gathered by a sensor over a fixed time.)  I want this to happen real time.  Is it possible?

Thanx much

[RavensFan · Accepted solution]

Graphs do not maintain a history, so when you plot something to a graph, you are plotting it fresh.  Any information that was already in the graph gets replaced.

What you need to do is store the information you are already plotting to the graph in a shift register.  Now when you want to add new data, you add that to the data in the shift register and send it to the graph again.

[amazed]

Thankyou Ravens Fan 

[DFGray]

Alternately, you can use the Value property or a local variable of the graph to get the old data, add your new data to the old, and replot.  This may be easier in some situations, but will almost always be slower.  It also limits your ability to actively manage your memory use.