This dialog allows you to specify parameters for vertical and/or horizontal error bars for one or more curves.
Display
Error bars are not drawn, regardless of the settings under Error Amount. 
Positive error bars extending up (or to the right, depending on the “Horizontal bars” setting) from each data point are drawn, subject to the conditions given by Error Amount. 
Negative error bars extending down (or to the left) from each data point are drawn. 
Both positive and negative error bars extending from each data point are drawn. 
Error Amount
Fixed value 
Error bars for every data point have the same constant magnitude for both the positive and negative errors (subject to the Display setting). 
Percentage 
Error bar magnitude is a percentage of the amplitude of the respective data point. 
Custom 
Error bars use different positive and negative values. Magnitude of the error bar is constant for all data points. 
Different error values for every point 
Error values are retrieved from another curve or from two curves. Curves that are selected to provide error values will not be drawn nor will they be considered when finding the plot extents. DPlot ignores the X values for these curves; the n'th point of the Plus curve is used as the error value for the n'th point of the selected curve, regardless of whether the x values match up. Both the + and  error curves should consist of positive magnitudes. 
NOTE: Error bars on bar charts will always be drawn parallel to the bars, regardless of whether you specify Vertical or Horizontal error bars.

Related macro commands 
How do I set error bars with unique values?
Page url:
https://www.dplot.com/help/index.htm?helpid_errorbars.htm