Charts "move" at the rate you add data to them. We have an application where we sample at 1KHz and want to view the data. If we updated by adding a data point every millisecond, the data would whiz by us, and we'd see very little. Instead, what we do is "chunk" the data 50 points at a time, and plotting either the average of the 50 points or the first of the 50 points (i.e. we either "smooth" or "decimate" the data). I'd originally chosen the Average operation, but my colleagues noticed that this had a (what I thought was a positive) effect of greatly decreasing the noise in the signal, noise that was, in fact, an indication that the electrodes were not properly placed. So I changed it to First, and everyone was happy (the sampled data at 1KHz remained unchanged, only the view was altered).
So if your chart zooms by too quickly, consider updating it less often, using either Averaging or Decimating of the input stream.
Bob Schor
