Often one has to use logarthmic charts on data which may change, or will be
typed in later. Usally a warning message pops up, whenever the sheet is
calculated. This keeps the user busy even in cases where this diagram is not
used.

In article ,
says...
Often one has to use logarthmic charts on data which may change, or will be
typed in later. Usally a warning message pops up, whenever the sheet is
calculated. This keeps the user busy even in cases where this diagram is not
used.

I am not sure I understand what data you want to plot but consider
replacing all values <= 0 with NA(). If necessary, use an additional
column to contain the data to be plotted. That way your computations
can continue to use the original data and the chart can use the new
data.